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Cited by 56Virus-based gene therapy researchRNA Interference and Gene DeliveryNeurogenetic and Muscular Disorders Research

Circumventing the packaging limit of AAV-mediated gene replacement therapy for neurological disorders

Open access
Marrone, Lara, Marchi, Paolo M., Azzouz, Mimoun·2022·Expert Opinion on Biological Therapy
DOI 10.1080/14712598.2022.2012148
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Abstract

Introduction Gene therapy provides the exciting opportunity of a curative single treatment for devastating diseases, eradicating the need for chronic medication. Adeno-associated viruses (AAVs) are among the most attractive vector carriers for gene replacement in vivo. Yet, despite the success of recent AAV-based clinical trials, the clinical use of these vectors has been limited. For instance, the AAV packaging capacity is restricted to ~4.7 kb, making it a substantial challenge to deliver large gene products.Areas covered In this review, we explore established and emerging strategies that circumvent the packaging limit of AAVs to make them effective vehicles for gene replacement therapy of monogenic disorders, with a particular focus on diseases affecting the nervous system. We report historical references, design remarks, as well as strengths and weaknesses of these approaches. We additionally discuss examples of neurological disorders for which such strategies have been attempted.Expert opinion The field of AAV-gene therapy has experienced enormous advancements in the last decade. However, there is still ample space for improvement aimed at overcoming existing challenges that are slowing down the progressive trajectory of this field.

AI snapshot

Written from the paper’s full text.

TL;DR

This review surveys strategies to overcome the ~4.7 kb AAV packaging limit for gene replacement in neurological disorders, including dual/triple vector reassembly and mini-gene approaches. It concludes that these approaches are promising but still require case-specific optimization, with most neurological applications preclinical and only two AAV products approved in the field.

Key findings

  • AAV packaging capacity is restricted to ~4.7 kb, while recombinant AAVs replace rep-cap with a promoter, therapeutic transgene, and polyadenylation signal; genes with coding sequences exceeding ~4 kb are oversized cargo. Dual/triple vector strategies include concatamerization/trans-splicing, overlapping, hybrid, and protein trans-splicing; triple AAV vectors can increase capacity up to 14 kb, and an HSV/AAV hybrid approach can deliver up to 150 kb.
  • Dual/triple vectors face reduced reassembly efficiency, possible aberrant or truncated products, safety concerns, and double/triple production costs. Overlapping vectors worked particularly well in muscle for DMD and dysferlinopathies but were less successful in terminally differentiated photoreceptors; hybrid and intein strategies improved retinal reassembly.
  • Mini-gene strategies replace full-length genes with truncated functional proteins. Examples include mini-dystrophin, miniCEP290 580-1180, AAV9-mini-TSC2 extending survival in a TSC2 mouse model, and AAV9-mini-agrin quadrupling lifespan in an MDC1A mouse model, though truncated proteins generally do not retain the full functional spectrum of the original protein.
  • In neurological disorders, Luxturna was approved in 2017 by the FDA and 2018 by the EMA for LCA, and Zolgensma was commercialized in 2019 for SMA at about $2.1 million in the USA and €1.9 million in Europe, with favorable safety at 6.2 years. Dual AAV for DFNB9 achieved 31–37% otoferlin levels in inner hair cells and partially restored auditory function in deaf mice.

Methods

  • Design: narrative review, not primary research, exploring established and emerging strategies to circumvent the AAV packaging limit for gene replacement therapy of monogenic disorders, with a focus on the nervous system.
  • Data/sample: literature and historical references; no primary dataset. The review discusses examples of neurological disorders for which these strategies have been attempted, summarized in figures and tables.
  • Main analysis: qualitative synthesis of design remarks, strengths, and weaknesses; disorders are grouped by target organ/system and organized in ascending order according to CDS size in Figure 4.

Limitations

  • Stated in the paper: dual/triple vector reassembly is not fully controllable, depends on simultaneous co-infection and cellular machinery, can produce heterogeneous or truncated products, raises safety issues, and doubles/triples production costs; mini-genes require detailed structure-function knowledge, and truncated proteins generally do not retain the whole functional spectrum of the full-length protein.
  • Stated in the paper: many strategies remain preclinical; for some diseases, human studies have not been reported or therapeutic effect remains unknown, and the list of unmet medical needs is non-comprehensive.
  • Evident from the text: as a narrative review, it does not provide systematic search criteria, quantitative synthesis, or primary experimental validation; comparative efficacy conclusions rely on cited studies and are not meta-analyzed.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1080/14712598.2022.2012148

Cites

133 of 134 references verified1 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

73 of 111 cited sources checked · 51 supported · 0 flagged · accuracy not yet measured

  • Premisecitation

    Reduced efficiency of reassembly in dual vectors does not enable reaching transgene expression levels typically observed with single AAV vectors.

    “An additional limitation is that the reduced efficiency of reassembly does not enable to reach the transgene expression levels typically observed with single AAV vectors [29].”
    Quote in the paperNot a substantial claim1 of 1 sources checked
  • Premisecitation

    Dual/triple vector approaches split the transgene into two or three separate sequences delivered by independent AAVs and allow reassembly to produce the full-length transgene upon co-infection.

    “In the so-called 'dual/triple vector approaches,' the transgene is split into either two or three separate sequences delivered by independent AAVs and allowed to reassemble to produce the full-length transgene upon co-infection [28].”
    Quote in the paperSubstantial claim1 of 1 sources checked
  • Premisecitation

    The AAV genome measures 4.7 kb.

    “Particularly, the AAV genome measures 4.7 kb and consists of two open-reading frames (rep, cap) flanked by T-shaped palindromic inverted terminal repeats (ITRs) of 145 base pairs.”
    • Also stated in: § Abstract · hedged
      “For instance, the AAV packaging capacity is restricted to ~4.7 kb, making it a substantial challenge to deliver large gene products.”
    Quote in the paperSubstantial claim1 of 1 sources checked
  • Premisecitation

    Maddalena et al. reported attempting subretinal injections of triple AAV2/8-ALMS1 vectors in Alms1 -/-mice without observing any stable phenotype amelioration.

    “Maddalena et al. have reported attempting subretinal injections of triple AAV2/8-ALMS1 vectors in Alms1 -/-mice without observing any stable phenotype amelioration [106].”
    Quote in the paperSubstantial claim1 of 1 sources checked
  • Premisecitation

    This is the first description of an AAV-based gene replacement therapy for TSC type 2.

    “This is the first description of an AAV-based gene replacement therapy for TSC type 2, whose further development will be particularly beneficial to TSC type 2 patients currently subjected to a regimen consisting of periodic administration of therapeutic drugs (e.g.rapamycin analogs), as gene replacement therapy would require a single AAV injection.”
    Quote in the paperSubstantial claim1 of 1 sources checked
  • May combine two claims. 39
  • Classified as probably not a substantial claim. 29

  • May combine two claims.

    Premisecitation

    Dual/triple AAV vectors can produce aberrant protein products from erroneous reassembly and/or untoward expression of individual split transgenes.

    “For instance, a general issue of dual/triple AAV vectors is the potential production of aberrant protein products from (i) erroneous reassembly and/or from (ii) the untoward expression of individual split transgenes.”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites [30] source

      The Introduction (page unavailable) identifies truncated proteins expressed from individual 5′ and 3′ halves of dual AAV vectors, supporting the split-transgene part of the claim. It discusses productive concatemer formation, and the Discussion mentions proper concatemerization of triple AAV vectors, but neither passage establishes that erroneous reassembly produces aberrant proteins or that the reported truncated-protein problem occurs with triple vectors. (LLM, conf=0.84)

      Experimental — accuracy not yet measured
    • cites [31] source

  • May combine two claims.

    Premisecitation

    AAV genomes can concatamerize in incorrect orientation, which can be at least partly counteracted using heterologous ITRs.

    “Unfortunately, subsequent studies highlighted the possibility for AAV genomes to concatamerize in the incorrect orientation [39], which could be at least partly counteracted using heterologous ITRs (derived from different AAV serotypes) [40].”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites [39] source
    • cites [40] source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Patients with MDC1A also present neurological abnormalities, including lissencephaly and agyria, intellectual disability, and epilepsy.

    “Importantly, patients also present neurological abnormalities, including lissencephaly and agyria, intellectual disability, and epilepsy [115].”
    Quote in the paperNot a substantial claim1 of 1 sources checked

  • May combine two claims.

    Premisecitation

    Dual AAV2/8 overlapping, trans-splicing and hybrid vectors have been developed and found to induce successful recombination of the transgene halves.

    “To overcome issues of clinical translatability linked to the generation of heterogeneous genomes from oversized vectors, dual AAV2/8 overlapping, trans-splicing and hybrid vectors have been developed and found to induce successful recombination of the transgene halves [99].”
    Quote in the paperSubstantial claim1 of 1 sources checked

  • May combine two claims.

    Premisecitation

    AAV2/8-CEP290 protein trans-splicing vectors have achieved reconstitution of the large CEP290 protein in the mouse retina, showing ameliorated retinal phenotypes.

    “Finally, the use of inteins has also been explored at the experimental level: AAV2/8-CEP290 protein trans-splicing vectors have achieved reconstitution of the large CEP290 protein in the mouse retina, showing ameliorated retinal phenotypes [64].”
    Quote in the paperSubstantial claim1 of 1 sources checked

  • May combine two claims.

    Premisecitation

    Serotype vectors with robust neuronal tropism and volumetric spread, such as AAV9, AAV8, and AAV1, are used for brain parenchyma administration and could aid with neurological illnesses that predominantly affect a specific brain region (e.g., Parkinson's disease).

    “Serotype vectors with robust neuronal tropism and volumetric spread, such as AAV9, AAV8, and AAV1, are used for this type of administration [80], and could certainly aid with neurological illnesses that predominantly affect a specific brain region (e.g.Parkinson's disease [81]).”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites [80] source
    • cites [81] source

  • May combine two claims.

    Premisecitation

    A mini-gene approach showed that intravenous injection of AAV9-mini-TSC2 in a TSC2-mouse model greatly extended survival, while reducing brain pathology.

    “Recently, a mini-gene approach showed that intravenous injection of AAV9-mini-TSC2 in a TSC2-mouse model greatly extended survival, while reducing brain pathology [111].”
    Quote in the paperSubstantial claim1 of 1 sources checked

  • May combine two claims.

    Premisecitation

    Overlapping vectors were not as successful in terminally differentiated photoreceptors, suggesting some targets may be intrinsically more refractory to this approach.

    “Contrarily, overlapping vectors were not as successful in terminally differentiated photoreceptors [29,49], suggesting that some targets may be intrinsically more refractory to this approach.”
    Quote in the paperNot a substantial claim2 of 2 sources checked

  • May combine two claims.

    Premisecitation

    Another study performed cochlear injections of dual AAV6 trans-splicing or hybrid vectors in Otof -/-mice, achieving 31-37% otoferlin protein levels in the inner hair cells compared to wild-type, which was sufficient to partially restore auditory function in deaf mice.

    “Another study performed cochlear injections of dual AAV6 trans-splicing or hybrid vectors in Otof -/-mice, achieving 31-37% otoferlin protein levels in the inner hair cells compared to wild-type, which was sufficient to partially restore auditory function in deaf mice [109].”
    Quote in the paperSubstantial claim1 of 1 sources checked

  • Classified as probably not a substantial claim.

    Premisecitation

    The MYO7A coding sequence spans 6.6 kb.

    “whose coding sequence spans 6.6 kb [95]”
    Quote in the paperSubstantial claim1 of 1 sources checked

  • May combine two claims.

    Premisecitation

    Subretinal administration of triple AAV vectors could reconstitute the full-length CDH23 in the mouse retina, although protein expression was found to be weak.

    “As shown by Maddalena and colleagues, subretinal administration of triple AAV vectors could reconstitute the full-length CDH23 in the mouse retina, although protein expression was found to be weak [106].”
    Quote in the paperNot a substantial claim1 of 1 sources checked

  • May combine two claims.

    Premisecitation

    An AAV8-mediated mini-gene strategy published by Tertrais et al. could only partially restore the exocytotic component of inner hair cells, without achieving hearing restoration in mice.

    “However, this method could only partially restore the exocytotic component of inner hair cells, without achieving hearing restoration in mice [110].”
    Quote in the paperNot a substantial claim1 of 1 sources checked

  • May combine two claims.

    Premisecitation

    The hybrid dual AAV strategy was initially proposed by Gosh and colleagues in 2008 and found to significantly improve transgene reassembly in a variety of studies thereafter.

    “The hybrid dual AAV strategy was initially proposed by Gosh and colleagues in 2008 [54] and found to significantly improve transgene reassembly in a variety of studies thereafter [29,49].”
    Quote in the paperNot a substantial claim2 of 3 sources checked
    • cites [54] source
    • cites [29] source

      The Discussion reports that hybrid AK outperformed trans-splicing for large-gene delivery to mouse photoreceptors, supporting an improvement in that setting. But it found no such advantage in retinal pigment epithelium or with the small EGFP transgene, and the Results report that hybrid AP produced the lowest transgene expression in vitro. The paper therefore does not support a general claim that hybrid dual AAV significantly improved reassembly across studies. (LLM, conf=0.88)

      Experimental — accuracy not yet measured
    • cites [49] source

      The Abstract and Discussion report that the hybrid approach gave the best reconstitution in vivo in mouse retina, and the Introduction says multiple studies found hybrid and trans-splicing among the most efficient dual-AAV approaches. But the Results report higher in-vitro reconstitution for the overlap approach than for hybrid, so this paper does not establish a consistent, significant improvement across a variety of studies. The separate attribution of the strategy’s 2008 origin is attached to a different citation. (LLM, conf=0.84)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Premisecitation

    A revised paradigm currently considers the use of muscle-specific promoters to prevent leaky expression, as well as systemic vector delivery for broader biodistribution via AAV9 and/or AAVrh74, which efficiently target both striated muscle and the CNS.

    “To overcome these limitations, a revised paradigm currently considers the use of muscle-specific promoters to prevent leaky expression, as well as systemic vector delivery for broader biodistribution via AAV9 and/or AAVrh74, which efficiently target both striated muscle and the CNS [123-125].”
    Quote in the paperSubstantial claim3 of 3 sources checked
    • cites [123] source

      Split into 2 atoms — 1 confirmed, 1 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

      Experimental — accuracy not yet measured
    • cites [124] source

      Split into 2 atoms — 1 confirmed, 1 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

      Experimental — accuracy not yet measured
    • cites [125] source

      Split into 2 atoms — 1 confirmed, 0 partially supported, 0 disputed, 0 misattributed, 1 unverifiable. Expand the claim to see per-atom verdicts.

      Experimental — accuracy not yet measured

  • May combine two claims.

    Premisecitation

    Triple AAV vectors can increase the genome capacity to up to 14 kb, thus expanding the possibilities for full-length reconstitution of large transgenes.

    “However, triple AAV vectors can increase the genome capacity to up to 14 kb, thus expanding the possibilities for full-length reconstitution of large transgenes [28].”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [28] source

      The Discussion says tri-AAV vectors may expand total carrying capacity and enable delivery of large genes such as full-length dystrophin. It gives the capacity as up to 15 kb, however, not the cited 14 kb. (LLM, conf=0.87)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Premisecitation

    Another study reported that the Cep290 rd16 mutation could be complemented in trans by a C-terminal CEP290 fragment delivered via AAV8-subretinal injection, which improved visual behavior in test mice.

    “Another study has favored a 'transcomplementation' strategy, reporting that the Cep290 rd16 mutation could be complemented in trans by a C-terminal CEP290 fragment delivered via AAV8-subretinal injection, which improved visual behavior in test mice [105].”
    Quote in the paperNot a substantial claim1 of 1 sources checked

  • May combine two claims.

    Premisecitation

    Al-Moyed and colleagues employed AAV2-OTOF hybrid vectors for cochlear delivery, demonstrating sustained correction of deafness in Otof -/-mice.

    “For example, Al-Moyed and colleagues have employed AAV2-OTOF hybrid vectors for cochlear delivery, demonstrating sustained correction of deafness in Otof -/-mice [108].”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [108] source

      The Materials and Methods describe cochlear delivery of an AAV2-Otof vector pair to Otof−/− mice, and the Results and Discussion report restored hearing thresholds that persisted for 20 weeks. The cited paper is by Akil and colleagues, however, not Al-Moyed and colleagues, so it does not support the claim’s attribution of the experiment to them. (LLM, conf=0.88)

      Experimental — accuracy not yet measured

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Early research conducted in murine and canine models of DMD paved the way for clinical investigation.

    “Early research conducted in murine and canine models of DMD [119-121] paved the way for clinical investigation.”
    Quote in the paperNot a substantial claim3 of 3 sources checked
    • cites [119] source
    • cites [120] source

      The Results describe gene-delivery experiments in mdx mice, a murine model of DMD, and the Discussion identifies potential clinical applications. Our copy does not describe research in a canine DMD model or establish that this work paved the way for clinical investigation; its mention of canine subjects concerns other AAV research. (LLM, conf=0.87)

      Experimental — accuracy not yet measured
    • cites [121] source

  • May combine two claims.

    Premisecitation

    Low transduction efficiencies and aberrant production of truncated proteins from single AAV vectors have been two major limitations.

    “the low transduction efficiencies as well as the aberrant production of truncated proteins from single AAV vectors have been two major limitations [103,104]”
    Quote in the paperSubstantial claim2 of 2 sources checked
    • cites [103] source

      The Introduction (page unavailable) says earlier dual-vector strategies had problems with expression levels and truncated protein forms. The Discussion (page unavailable) describes truncated ABCA4 protein previously generated from an individual 3′ vector, but says optimization reduced it to undetectable levels. The paper does not establish low transduction efficiency specifically, or characterize these as two major limitations. (LLM, conf=0.84)

      Experimental — accuracy not yet measured
    • cites [104] source

      The Discussion (page unavailable) describes the fragmented dual-vector approach as less efficient than other dual-vector methods and predicts that its hybrid transcripts could produce truncated proteins if translated. It does not establish low transduction efficiency for single AAV vectors or demonstrate aberrant production of truncated proteins; the Introduction says translation was not detectable by western blot. (LLM, conf=0.86)

      Experimental — accuracy not yet measured

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The inner ear is a confined compartment of the nervous system that has become the target of increasing gene therapy research efforts for oversized transgenes.

    “As is the case for the eye, the inner ear is a confined compartment of the nervous system that has become the target of increasing gene therapy research efforts for oversized transgenes [127].”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [127] source

      The Introduction describes gene delivery to inner-ear cells, and the Abstract reports recent dual-AAV delivery of a large gene sequence to inner hair cells, supporting the point about research on oversized transgenes. The passages do not characterize the inner ear as a confined compartment of the nervous system or establish that research efforts are increasing. (LLM, conf=0.82)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Premisecitation

    Although some homology-directed repair has been observed in non-dividing cells such as neurons, other DNA repair pathways than homologous recombination are more active in these long-lived postmitotic cells.

    “Although a certain level of homology-directed repair has been observed in non-dividing cells, such as neurons [52], other DNA repair pathways than homologous recombination are more active in these long-lived postmitotic cells [53].”
    Quote in the paperSubstantial claim2 of 2 sources checked

  • May combine two claims.

    Premisecitation

    A follow-up safety study revealed a favorable safety profile of Zolgensma following 6.2 years from dosing and provided evidence of sustained clinical durability.

    “Additionally, a follow-up safety study has revealed a favorable safety profile of the therapy following 6.2 years from dosing, as well as providing evidence of sustained clinical durability [92].”
    Quote in the paperNot a substantial claim1 of 1 sources checked

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

    Interpretationcitation

    Complex neurodegenerative disorders with systemic abnormalities, such as ARSACS and certain forms of HSP, would also benefit from a gene therapeutic approach developed from any of the methods discussed in this review.

    “Yet, complex neurodegenerative disorders with systemic abnormalities, such as Autosomal Recessive Spastic Ataxia of Charlevoix-Saguenay (ARSACS) [128] and certain forms of Hereditary Spastic Paraplegia (HSP, including SPG11 and SPG15-HSPs) [129], would also benefit from a gene therapeutic approach developed from any of the methods discussed in this review.”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites [128] source
    • cites [129] source

  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation

    Protein trans-splicing joins two separate polypeptides into one through a peptide bond, mediated by inteins.

    “In fact, protein trans-splicing consists of joining two separate polypeptides into one through a peptide bond [56].”
    Quote in the paperSubstantial claim1 of 1 sources checked

  • May combine two claims.

    Premisecitation

    More recently, the same group upgraded to the AAV9 serotype and showed that AAV9mini-agrin vectors additionally ameliorated peripheral neuropathy and cognition, thus offering superior therapeutic effects compared to the AAV1 serotype.

    “More recently, the same group upgraded to the AAV9 serotype and showed that AAV9mini-agrin vectors additionally ameliorated peripheral neuropathy and cognition, thus offering superior therapeutic effects compared to the AAV1 serotype [117].”
    Quote in the paperSubstantial claim1 of 1 sources checked

  • May combine two claims.

    Interpretationcitation

    Efficient trans-splicing relies on the chosen sequences, making it crucial to optimize vector design on a case-to-case basis.

    “Importantly, it was also observed that particular care should be put into selecting a splitting point and splicing signals, as efficient trans-splicing relies on the chosen sequences, making it crucial to meticulously optimize vector design on a case-to-case basis [41].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [41] source

  • Probably not a substantial claim: may not pass S1 (asserted), S3 (load-bearing).

    Premisecitation

    One ambitious goal of UshTher is to assess the potentials of dual AAVs in humans for the first time.

    “In fact, one ambitious goal of UshTher is to assess the potentials of dual AAVs in humans for the first time.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites https://www.ushther.eu/

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Interpretationreasoning

    This approach harbors important limitations, such as potential contamination by helper viruses during production, inability of the AAVS1 site to support transgene expression in some cell types, and disruption of the PPP1R12 C gene.

    “Despite this proofof-principle, this approach harbors important limitations, such as (i) the potential contamination by helper viruses during production, (ii) the inability of the AAVS1 site to support transgene expression in some cell types, and (iii) the fact that integration in the AAVS1 site disrupts the PPP1R12 C gene, which encodes a protein whose function is still unclear.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Voretigene Neparvovec (Luxturna) received FDA authorization in 2017 and EMA authorization in 2018 for the treatment of Leber Congenital Amaurosis (LCA) linked to RPE65 mutations.

    “Voretigene Neparvovec, also known as Luxturna, received authorization in 2017 (by the FDA) and in 2018 (by the EMA) for the treatment of Leber Congenital Amaurosis (LCA), an inherited retinal disease linked to mutations in the RPE65 gene [86].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [86] source

  • Classified as probably not a substantial claim. May combine two claims.

    Interpretationreasoning

    Further development of AAV-based gene replacement therapy for TSC type 2 will be particularly beneficial to TSC type 2 patients currently subjected to periodic administration of therapeutic drugs, as gene replacement therapy would require a single AAV injection.

    “whose further development will be particularly beneficial to TSC type 2 patients currently subjected to a regimen consisting of periodic administration of therapeutic drugs (e.g.rapamycin analogs), as gene replacement therapy would require a single AAV injection.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationnone given

    AAV injections into the brain parenchyma can mechanically bypass the BBB, but they require invasive neurosurgery and present substantial risks for patients.

    “AAV injections into the brain parenchyma can mechanically bypass the BBB, but they require invasive neurosurgery and present substantial risks for patients.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S2 (checkable).

    Interpretationreasoning

    Timing is of the essence when approaching disorders of the nervous system.

    “Hence, timing is of the essence when approaching disorders of the nervous system.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given

    Recombinant AAVs have emerged as the platform of choice to deliver gene therapeutic products.

    “Recombinant AAVs have emerged as the platform of choice to deliver gene therapeutic products.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Interpretationnone given

    Many neurological conditions would necessitate widespread therapeutic gene transfer throughout the entire CNS.

    “However, many other conditions would necessitate widespread therapeutic gene transfer throughout the entire CNS.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Zolgensma has led to increased probability of survival and improved motor skills in SMA type 1 infants when compared to historical controls.

    “Zolgensma has led to increased probability of survival and improved motor skills in SMA type 1 infants when compared to historical controls [91].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [91] source

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given

    Most of the research on gene replacement therapy for disorders of the nervous system has been focused on treating inherited retinal diseases.

    “Most of the research on gene replacement therapy for disorders of the nervous system has been focused on treating inherited retinal diseases.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    The CNS microenvironment is shielded by a robust physical barrier (the BBB), making delivery of large particles to the CNS (including AAV vectors) a relevant challenge.

    “As a result, the CNS microenvironment is shielded by a robust physical barrier, which makes the delivery of large particles to the CNS (including of AAV vectors) a relevant challenge.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationnone given

    The treatment of neurological diseases caused by mutations in oversized genes presents an additional degree of complexity compared to LCA and SMA.

    “This particularly applies to the treatment of neurological diseases caused by mutations in oversized genes, which present one additional degree of complexity, when compared to LCA and SMA.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    This HSV/AAV hybrid vector ensured functional expression of ATM cDNA in AT human cells as well as in AAVS1-transgenic Atm -/ -mouse cells.

    “Interestingly, this HSV/AAV hybrid vector ensured functional expression of ATM cDNA in AT human cells as well as in AAVS1-transgenic Atm -/ -mouse cells.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [113] source

  • May combine two claims.

    Premisecitation

    In 2005, the Xiao lab showed that systemic delivery of AAV1/2-miniagrin vectors into different muscles of an MDC1A-mouse model quadrupled its lifespan, improving whole-body growth and motility.

    “In 2005, the Xiao lab showed that systemic delivery of AAV1/2-miniagrin vectors into different muscles of an MDC1A-mouse model quadrupled its lifespan, improving whole-body growth and motility [116].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [116] source

  • May combine two claims.

    Interpretationreasoning

    The efficiency of transgene reconstitution in dual strategies depends on simultaneous infection of the target cell with both therapeutic AAVs and the competence of the cellular molecular machinery mediating reassembly, which may differ between cell types and individuals.

    “The efficiency of transgene reconstitution depends on (i) the simultaneous infection of the target cell with both therapeutic AAVs and (ii) the competence of the cellular molecular machinery mediating reassembly, which may differ from cell type to cell type as well as from individual to individual.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Onasemnogene Abeparvovec (Zolgensma) was commercialized in 2019 to treat children with Spinal Muscular Atrophy (SMA).

    “In 2019, Onasemnogene Abeparvovec was commercialized under the brand name of Zolgensma to treat children with the lethal motor neuron disease Spinal Muscular Atrophy (SMA) [89].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [89] source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Interpretationreasoning

    These successes have set an example for the development of other AAV-based gene products, although most experimental vectors are still far from entering clinical testing.

    “These successes have undoubtedly set an example for the development of other AAV-based gene products, although most experimental vectors are still far from entering clinical testing.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing), S4 (based).

    Interpretationnone given

    More complex neurological disorders with systemic involvement have been requiring more intense efforts.

    “Contrarily, more complex neurological disorders with systemic involvement have been requiring more intense efforts.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    Gene replacement therapy for neurological disorders must be performed in vivo, raising the issue of the most appropriate route of administration for optimal biodistribution.

    “Therefore, gene replacement therapy for neurological disorders must be performed in vivo, raising the issue of the most appropriate route of administration for optimal biodistribution.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    The presence of a highly recombinogenic sequence in hybrid vectors should favour reassembly in the correct orientation, and reassembly may still occur via concatamerization/trans-splicing in the absence of recombination.

    “This was not surprising, considering that the presence of a highly recombinogenic sequence should favour reassembly in the correct orientation, and that reassembly may still occur via concatamerization/ trans-splicing in the absence of recombination.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisereasoning

    A consortium (UshTher) has been established to evaluate the feasibility of dual AAV strategies for the treatment of Usher syndrome 1B in the clinic.

    “Based on these promising results, a consortium has been recently established to evaluate the feasibility of dual AAV strategies for the treatment of Usher syndrome 1B in the clinic (UshTher, https://www.ushther.eu/).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites https://www.ushther.eu/

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Premisecitation

    Preliminary data from two of these trials showed welltolerated treatment, sustained protein production in muscles, and improved motor function; a handful of serious adverse events were reported within 4 weeks post-dosing, but patients had fully recovered by their latest medical examination.

    “Preliminary data from two of these trials showed welltolerated treatment, sustained protein production in muscles, and improved motor function; a handful of serious adverse events were reported within 4 weeks post-dosing, but patients had fully recovered by their latest medical examination (https://mdaconference.org/node/1152 & https://musculardy strophynews.com/pf-06939926/).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites https://mdaconference.org/node/1152

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites https://musculardy strophynews.com/pf-06939926/

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning

    These achievements have been facilitated by the easy accessibility of this target tissue as well as its circumscribed nature, as opposed to other conditions affecting the nervous system more broadly.

    “These achievements have been facilitated by the easy accessibility of this target tissue as well as its circumscribed nature, as opposed to other conditions affecting the nervous system more broadly.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Interpretationnone given

    Despite promising results from several studies, only a handful of products generated through these strategies have made it to clinical testing so far, suggesting the need to further improve current methods.

    “Despite promising results from several studies, only a handful of products generated through these strategies have made it to clinical testing so far, suggesting the need to further improve current methods.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Interpretationreasoning

    Because certain serotype vectors, such as AAV9, can cross the BBB to transduce both neurons and glia, systemic delivery via intravenous infusion appears to be an appealing option due to its simplicity.

    “Because certain serotype vectors, such as AAV9, can cross the BBB to transduce both neurons and glia, systemic delivery via intravenous infusion appears to be an appealing option due to its simplicity.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    MYO7A produces a myosin isoform predominantly expressed in cochlear hair cells, photoreceptors and retinal pigmented epithelium.

    “produces a myosin isoform predominantly expressed in cochlear hair cells, photoreceptors and retinal pigmented epithelium [96]”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [96] source

  • May combine two claims.

    Interpretationreasoning

    The therapeutic effect of this approach remains unknown, as no retinal phenotype was investigated in this study.

    “The therapeutic effect of this approach remains unknown, as no retinal phenotype was investigated in this study.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning

    The combined AAV vector regimen might achieve improved co-infection rates in the subretinal space of larger animals.

    “suggesting that the combined AAV vector regimen might achieve improved co-infection rates in the subretinal space of larger animals.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    The nature and length of the overlap region are critical for reassembly in the overlapping strategy and may need extensive optimization.

    “Here, the nature and length of the overlap region seem to represent critical elements for reassembly and may need extensive optimization.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [42] McClements ME, 2017, Yale J Biol Med

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing), S4 (based).

    Interpretationnone given

    The portfolio of strategies aimed at correcting diseases caused by mutations in large genes is slowly but tangibly expanding.

    “However, the portfolio of strategies aimed at correcting diseases caused by mutations in large genes is slowly but tangibly expanding.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

    Interpretationnone given

    A fascinating possibility to solve the size-limit problem would be to modify the AAV capsid to achieve higher capacity.

    “While the strategies described above focus on adapting the cargo to fit the limited size of the AAV capsid, a fascinating possibility to solve the size-limit problem would be to modify the AAV capsid to achieve higher capacity.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    These particles were reported to range between 35 nm and 70 nm in size and be able to package genomes from multiple serotypes.

    “These particles were reported to range between 35 nm and 70 nm in size and be able to package genomes from multiple serotypes.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [135] source

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given

    This approach carries high risks, as the capsid sites that could afford changes without affecting titers, yield and efficacy are very limited.

    “This approach carries high risks, as the capsid sites that could afford changes without affecting titers, yield and efficacy are very limited.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S1 (asserted), S3 (load-bearing).

    Premisecitation

    Researchers are assessing a series of AAV capsid variants carrying extra lysine and arginine residues within the capsid lumen, which, due to their positive charge, should induce condensation of the DNA payload and indirectly increase vector capacity by cargo compaction.

    “Researchers are additionally assessing a series of AAV capsid variants carrying extra lysine and arginine residues within the capsid lumen, which, due to their positive charge, should induce condensation of the DNA payload and indirectly increase vector capacity by cargo compaction [134].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [134] source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premiseown data

    The list of neurological disorders lacking published gene therapeutic options is still long.

    “The list of neurological disorders lacking published gene therapeutic options is still long (Figure 4, 'unmet medical needs').”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Figure 4

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

61 of 61

  • The paper relies on this without support.

    Gene replacement therapy provides a curative single treatment for devastating diseases, eradicating the need for chronic medication.

    “Gene therapy provides the exciting opportunity of a curative single treatment for devastating diseases, eradicating the need for chronic medication.”

  • The paper relies on this without support.

    Despite the success of recent AAV-based clinical trials, the clinical use of AAV vectors has been limited.

    “Yet, despite the success of recent AAV-based clinical trials, the clinical use of these vectors has been limited.”

  • The paper relies on this without support.

    Usher 1B is an autosomal recessive disease characterized by deafness and blindness resulting from mutations in the MYO7A gene.

    “Usher 1B (USH1, MIM 276900) is an autosomal recessive disease characterized by deafness and blindness resulting from mutations in the MYO7A gene, whose coding sequence spans 6.6 kb [95] and produces a myosin isoform predominantly expressed in cochlear hair cells, photoreceptors and retinal pigmented epithelium [96].”

  • The paper relies on this without support.

    The development of a gene therapy for Usher 1B has been largely hampered by difficulties in identifying robust phenotypes in animal models, especially with respect to retinal dysfunction and degeneration.

    “The development of a gene therapy for Usher 1B has been largely hampered by difficulties in identifying robust phenotypes in animal models, especially with respect to retinal dysfunction and degeneration, which is currently untreatable.”

  • The paper relies on this without support.

    Recent advances have led to the identification of reliable readouts of retinal function in Myo7a-null mice, which has rapidly accelerated the gene therapy research output.

    “However, recent advances have led to the identification of reliable readouts of retinal function in Myo7a-null mice, which has rapidly accelerated the gene therapy research output.”

  • The paper relies on this without support.

    Stargardt disease is a common form of hereditary recessive macular dystrophy caused by mutations in the ABCA4 gene.

    “Stargardt disease (STGD1, MIM 248200) is a common form of hereditary recessive macular dystrophy caused by mutations in the ABCA4 gene, which encodes the retinal-specific ABCA4 protein involved in transporting retinoids from photoreceptors to the retinal pigment epithelium.”

  • The paper relies on this without support.

    ABCA4 encodes a retinal-specific protein involved in transporting retinoids from photoreceptors to the retinal pigment epithelium.

    “which encodes the retinal-specific ABCA4 protein involved in transporting retinoids from photoreceptors to the retinal pigment epithelium.”

  • The paper relies on this without support.

    Losing ABCA4 protein leads to a progressive bilateral decline in central vision that begins in adolescence, accompanied by lipofuscin deposits around the macula.

    “Losing this protein leads to a progressive bilateral decline in central vision that begins in adolescence, accompanied by lipofuscin deposits around the macula.”

  • The paper relies on this without support.

    The ABCA4 coding sequence is 6.8 kb.

    “Because of the large size of the ABCA4 coding sequence (6.8 kb), dual AAV strategies have been explored to deliver the ABCA4 gene product for gene replacement therapy [100].”

  • The paper relies on this without support.

    Intein vectors have also been used, particularly targeting mice, pigs and human retinal organoids.

    “Intein vectors have also been used, particularly targeting mice, pigs and human retinal organoids.”

  • The paper relies on this without support.

    LCA10 is a severe retinal dystrophy, causing blindness/severe visual impairment at birth or during the first months of life.

    “Leber congenital amaurosis 10 (LCA10, MIM 611755) is a severe retinal dystrophy, causing blindness/severe visual impairment at birth or during the first months of life.”

  • The paper relies on this without support.

    LCA10 is caused by mutations in the CEP290 gene, which encodes for a protein required for the correct localization of ciliary and phototransduction proteins in retinal photoreceptor cells.

    “LCA10 is caused by mutations in the CEP290 gene, which encodes for a protein required for the correct localization of ciliary and phototransduction proteins in retinal photoreceptor cells.”

  • The paper relies on this without support.

    The impossibility to package the long CEP290 cDNA (7.4 kb) into a single AAV vector has delayed the development of gene replacement strategies for LCA10.

    “The impossibility to package the long CEP290 cDNA (7.4 kb) into a single AAV vector has delayed the development of gene replacement strategies for LCA10.”

  • The paper relies on this without support.

    Because CEP290 is a multi-domain-structure protein, minigenes designed to maintain essential functional properties have been evaluated.

    “However, because CEP290 is a multi-domain-structure protein, minigenes designed to maintain essential functional properties have been evaluated.”

  • The paper relies on this without support.

    Human studies for LCA10 gene replacement have not been reported to date.

    “However, human studies have not been reported to date.”

  • The paper relies on this without support.

    Usher 1D is a severe form of autosomal recessive blindness-deafness caused by mutations in CDH23 (cDNA, 10.1 kb).

    “Usher 1D (USH1D, MIM 601067) is a severe form of autosomal recessive blindness-deafness caused by mutations in CDH23 (cDNA, 10.1 kb), which encodes for Cadherin-related family member 23, a protein thought to be involved in stereocilia organization and hair bundle formation.”

  • The paper relies on this without support.

    CDH23 encodes Cadherin-related family member 23, a protein thought to be involved in stereocilia organization and hair bundle formation.

    “which encodes for Cadherin-related family member 23, a protein thought to be involved in stereocilia organization and hair bundle formation.”

  • The paper relies on this without support.

    The cDNA of CDH23 exceeds the packaging limit of both single and dual AAVs.

    “Importantly, the cDNA of CDH23 exceeds the packaging limit of both single and dual AAVs.”

  • The paper relies on this without support.

    Alstrom syndrome is an autosomal recessive disease, manifesting with a broad spectrum of symptoms, including obesity, insulin resistance, retinal dystrophy and hearing loss.

    “Alstrom syndrome (ALMS, MIM 203800) is an autosomal recessive disease, manifesting with a broad spectrum of symptoms, including obesity, insulin resistance, retinal dystrophy and hearing loss.”

  • The paper relies on this without support.

    Non-syndromic deafness (DFNB9) is one of the most frequent recessive forms of congenital deafness and it is caused by mutations in the OTOF gene (cDNA, 6 kb) producing the otoferlin protein, essential for inner hair cell exocytosis and vesicle replenishment.

    “Non-syndromic deafness (DFNB9, MIM 601071) is one of the most frequent recessive forms of congenital deafness and it is caused by mutations in the OTOF gene (cDNA, 6 kb) producing the otoferlin protein, essential for inner hair cell exocytosis and vesicle replenishment.”

  • The paper relies on this without support.

    Dual AAV vector approaches have conceptually shown that production of the full-length otoferlin protein can be effectively achieved.

    “Dual AAV vector approaches have conceptually shown that production of the full-length otoferlin protein can be effectively achieved.”

  • The paper relies on this without support.

    Tuberous sclerosis complex (TSC) is an autosomal dominant multi-system disorder characterized by benign tumors in multiple organs, accompanied by CNS manifestations such as epilepsy, learning deficits and behavioral problems.

    “Tuberous sclerosis complex (TSC, MIM 191100 & 613,254) is an autosomal dominant multi-system disorder characterized by the appearance of benign tumors in multiple organs (i.e.brain, skin, heart, kidneys, lungs), accompanied by CNS manifestations such as epilepsy, learning deficits and behavioral problems.”

  • The paper relies on this without support.

    TSC is caused by loss-of-function mutations in either TSC1 or TSC2, encoding hamartin and tuberin, which normally inhibit mTORC1-mediated cell growth and proliferation.

    “TSC is caused by loss-of-function mutations in either of the tumor-suppressor genes TSC1 or TSC2, encoding hamartin and tuberin, which normally inhibit mTORC1-mediated cell growth and proliferation.”

  • The paper relies on this without support.

    Hamartin's cDNA (3.5 kb) fits into a single AAV vector, while tuberin's cDNA is too large (5.4 kb).

    “Whereas hamartin's cDNA (3.5 kb) fits into a single AAV vector, tuberin's cDNA is too large (5.4 kb).”

  • The paper relies on this without support.

    Neurofibromatosis type 1 (NF1) is an autosomal dominant disorder associated with increased risk of tumor growth along nerves throughout the body.

    “Neurofibromatosis type 1 (NF1, MIM 162200) is an autosomal dominant disorder associated with increased risk of tumor growth along nerves throughout the body.”

  • The paper relies on this without support.

    NF1 is caused by loss-of-function mutations in the NF1 tumor suppressor gene, which lead to hyperactivation of signaling pathways of cell proliferation and survival.

    “NF1 is caused by loss-of-function mutations in the NF1 tumor suppressor gene, which lead to hyperactivation of signaling pathways of cell proliferation and survival.”

  • The paper relies on this without support.

    The full-length NF1 cDNA is too large for packaging into a single AAV vector (8.5 kb).

    “Although the full-length NF1 cDNA is too large for packaging into a single AAV vector (8.5 kb), one of its encoded domains, called 'GTPase activating proteinrelated domain (GRD),' is thought to be sufficient to deactivate cellular proliferation pathways, and due to its small size (~1 kb), it can be contained within a single AAV vector.”

  • The paper relies on this without support.

    One of NF1's encoded domains, called 'GTPase activating proteinrelated domain (GRD),' is thought to be sufficient to deactivate cellular proliferation pathways, and due to its small size (~1 kb), it can be contained within a single AAV vector.

    “one of its encoded domains, called 'GTPase activating proteinrelated domain (GRD),' is thought to be sufficient to deactivate cellular proliferation pathways, and due to its small size (~1 kb), it can be contained within a single AAV vector.”

  • The paper relies on this without support.

    Ataxia-telangiectasia (AT) is a devastating genetic syndrome involving neurodegeneration, immunodeficiency and cancer predisposition due to mutations in the ATM gene (cDNA, 9.1 kb).

    “Ataxia-telangiectasia (AT, MIM 208900) is a devastating genetic syndrome involving neurodegeneration, immunodeficiency and cancer predisposition due to mutations in the ATM gene (cDNA, 9.1 kb).”

  • The paper relies on this without support.

    The encoded protein kinase, ATM, is a master regulator of DNA double-strand breaks and stress responses.

    “The encoded protein kinase, ataxia telangiectasia mutated (ATM), is a master regulator of DNA double-strand breaks and stress responses.”

  • The paper relies on this without support.

    LAMA2-related congenital muscular dystrophy (MDC1A) is the most common and fatal form of early-onset inherited muscular dystrophy, characterized by hypotonia, delayed motor development and relentless muscle weakening.

    “LAMA2-related congenital muscular dystrophy, also termed muscular dystrophy type 1A (MDC1A, MIM 607855), is the most common and fatal form of early-onset inherited muscular dystrophy, characterized by hypotonia, delayed motor development and relentless muscle weakening.”

  • The paper relies on this without support.

    Currently, there is no treatment for MDC1A.

    “Currently, there is no treatment for this debilitating disease.”

  • The paper relies on this without support.

    Mutations in the LAMA2 gene lead to deficiency of laminin α2, a subunit of laminin 2 (merosin).

    “Mutations in the LAMA2 gene lead to deficiency of laminin α2, a subunit of laminin 2 (merosin).”

  • The paper relies on this without support.

    The extent of the laminin α2 cDNA (>9 kb) precludes its packaging into a single AAV vector.

    “Unfortunately, the extent of the laminin α2 cDNA (>9 kb) precludes its packaging into a single AAV vector.”

  • The paper relies on this without support.

    A suggested solution to this limitation has been the use of a condensed version of agrin, which is a functional substitute sharing some fundamental properties with laminin α2 and thus able to structurally compensate for laminin-α2 deficiency.

    “A suggested solution to this limitation has been the use of a condensed version of agrin, which is a functional substitute sharing some fundamental properties with laminin α2 (i.e.α-dystroglycan binding, basement membrane-sarcolemma linkage) and thus able to structurally compensate for laminin-α2 deficiency.”

  • The paper relies on this without support.

    Duchenne muscular dystrophy (DMD) is an X-linked disease characterized by progressive muscle waste due to lack of dystrophin, instrumental for the structural integrity of muscle tissue, but evidence suggests intellectual disability as a consistent feature of DMD.

    “Duchenne muscular dystrophy (DMD, MIM 310200) is an X-linked disease characterized by progressive muscle waste due to lack of a protein (dystrophin) instrumental for the structural integrity of muscle tissue, but evidence suggests intellectual disability as a consistent feature of DMD.”

  • The paper relies on this without support.

    Gene replacement therapy for DMD relies on the delivery of mini or micro-dystrophin genes well below the size of the 14 kb-long dystrophin cDNA.

    “Gene replacement therapy for DMD relies on the delivery of mini or micro-dystrophin genes well below the size of the 14 kb-long dystrophin cDNA.”

  • The paper relies on this without support.

    Three pharma companies have taken over the assessment of DMD gene therapy for human use: NCT03368742 (Solid Biosciences, LLC), NCT03769116 (Sarepta Therapeutics, Inc.), NCT03362502 (Pfizer).

    “Very recently, three pharma companies have taken over the assessment of DMD gene therapy for human use: NCT03368742 (Solid Biosciences, LLC), NCT03769116 (Sarepta Therapeutics, Inc.), NCT03362502 (Pfizer).”
38 of 38

Cites

Flagged first, then by citations

Research works printed but not linked: 2

  1. 10.1093/nar/gkn1096 · DOI
  2. McClements ME, 2017, Yale J Biol Med, 90, 611

Cited by

Sorted by citations

Related

Authors
Marrone, L., Marchi, P. M., & Azzouz, M.
Affiliations
University of Sheffield (GB)
Corresponding author
Azzouz, Mimoun
ORCID
Venue
Expert Opinion on Biological Therapy
Publisher
Informa UK Limited
Published
2022-01-06
Volume
22
Issue
9
Pages
1163-1176
ISSN
  • 1471-2598 (ISSN-L)
  • 1744-7682
DOI
10.1080/14712598.2022.2012148
OpenAlex
W4200272929
Semantic Scholar
54d1e792ee701b66cb7c6ba7d4d7fe7c9801713f
Cited by
56
References
133
Citations by year
2026: 17 · 2025: 12 · 2024: 9 · 2023: 14 · 2022: 4
FWCI
1.03
Type
journal article
Language
en
Open access
Licence
Locations
  • Expert Opinion on Biological Therapy (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • White Rose Research Online (University of Leeds, The University of Sheffield, University of York) (acceptedVersion)
Funders
  • Maddi Foundation
  • British Neuropathological Society
  • European Research Council (294745)
  • MRC (MR/G1001492)
  • IMI (945473)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Genetics › Virus-based gene therapy research
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › RNA Interference and Gene Delivery
  • Health Sciences › Medicine › Genetics › Neurogenetic and Muscular Disorders Research
Keywords
adeno-associated virus vectors, gene replacement therapy, neurological disorders, monogenic disorders, gene therapy vectors
MeSH terms
Dependovirus, Genetic Vectors, Humans, Nervous System Diseases, Genetic Therapy

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-28.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-28.

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