Cited by 3Renal Diseases and GlomerulopathiesLipid metabolism and disordersChronic Kidney Disease and Diabetes

Lipoprotein glomerulopathy with a novel apolipoprotein E variant, APOE Kanto (Asp 151dup)

Open access
Yokochi, Akio, Matsunaga, Akira, Kanemoto, Keiko, Tominaga, Naoto, Uda, Susumu, Saito, Takao·2024·CEN Case Reports

Abstract

A 33-year-old Japanese man was admitted for possible kidney disease because of massive proteinuria. Laboratory findings were characterized by marked urinary protein of 4.7 g/day and high-serum triglyceride levels of 266 mg/dL. Renal biopsy revealed segmental proliferation in the mesangium and lipoprotein thrombi in the glomerular capillary. These results suggested that the diagnosis was lipoprotein glomerulopathy (LPG), although serum apolipoprotein E (apo E) levels were within normal ranges. The APOE phenotype was identified as E2/3 by isoelectric focusing polyacrylamide gel electrophoresis. Direct DNA sequencing analyses for apo E identified a duplication of amino acid 151, aspartic acid, and the gene mutation was named APOE Kanto. APOE gene mutations due to amino acid duplication are rare, and this is the first report showing that amino acid duplication among apo E gene mutations is involved in LPG. It is also noteworthy that the patient developed end-stage kidney disease after over than 10 years despite fibrate treatment.

AI snapshot

Written from the paper’s full text.

TL;DR

A 33-year-old Japanese man with lipoprotein glomerulopathy (LPG) was found to have a novel APOE variant, APOE Kanto (Asp151dup), caused by a heterozygous duplication of aspartic acid at codon 151. He progressed to end-stage kidney disease over more than 10 years despite fibrate treatment.

Key findings

  • The patient presented with massive proteinuria (4.7 g/day), serum triglyceride 266 mg/dL, total cholesterol 229 mg/dL, LDL-cholesterol 123 mg/dL, HDL-cholesterol 50 mg/dL, and a normal serum apo E level of 4.3 mg/dL.
  • Renal biopsy showed LPG-compatible findings: of 19 glomeruli, 4 had global sclerosis and 7 had segmental mesangial-cell proliferation and matrix increase with lipoprotein thrombi; immunofluorescence was negative, and electron microscopy showed lamellar thrombus-like substances with vacuoles.
  • APOE phenotyping showed apo E2/E3, and DNA sequencing identified a heterozygous duplication, c.508_510dupGAT, leading to Asp151dup (p.Asp169dup), named APOE Kanto; no other mutations were found in APOE exons 3 and 4.
  • The authors state this is the first report of LPG with an APOE mutation due to duplicated amino acid residues; the patient’s proteinuria decreased from about 3 g/gCr to around 1.0 g/gCr after 3 years, but eGFR fell from 50 to 25 mL/min/1.73 m² over 13 years, and ESKD developed after fibrate was discontinued when serum creatinine reached 2.5 mg/dL.

Methods

  • Single case report with clinical, laboratory, renal biopsy, and long-term follow-up data.
  • Serum APOE phenotype analyzed by isoelectric focusing polyacrylamide gel electrophoresis; APOE exons 3 and 4 were PCR-amplified, cloned, and 12 clones were sequenced.
  • An amplification refractory mutation system (ARMS) was used to confirm the c.508_510dupGAT mutation.

Limitations

  • The authors state it is difficult to discuss whether the double amino acid duplication alone can cause the etiological mechanism of LPG, and that accumulation of more cases with amino acid duplication in APOE is required.
  • Evident from the text: this is a single case report without functional assays (e.g., receptor-binding or thermodynamic studies), so causality and mechanism for APOE Kanto remain unproven.
  • Evident from the text: the comparison with other LPG cases is limited to a small number of Japanese cases with normal apo E levels, and no systematic case–control or genotype–phenotype analysis is presented.

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

Integrity signals

Registry

Crossref · 10.1007/s13730-024-00920-z

Cites

15 of 15 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

3 of 17 cited sources checked · 3 supported · 0 flagged

  • Premisecitation

    Until now, out of 45 cases diagnosed as LPG in Japan, there is only one with APOE Tsukuba and two with APOE Osaka/Kurashiki in which the ranges of apo E are normal.

    “Until now, out of 45 cases diagnosed as LPG in Japan, there is only one with APOE Tsukuba [7] and two with APOE Osaka/Kurashiki [8,9] in which the ranges of apo E are normal.”
    Quote in the paperSubstantial claim2 of 3 sources checked
    • cites [7] Hagiwara M, Yamagata K, Matsunaga T, et al. A novel apolipoprotein E mutation, ApoE Tsukuba (Arg 114 Cys), in lipoprotein glomerulopathy. Nephrol Dial Transplant. 2008;23:381–4. source
    • cites [8] Mitani A, Ishigami M, Watase K, Minakata T, Yamamura T. A novel apolipoprotein E mutation, ApoE Osaka (Arg158 Pro), in a dyslipidemic patient with lipoprotein glomerulopathy. J Atheroscler Thromb. 2011;18:531–5. source
    • cites [9] Tokura T, Itano S, Kobayashi S, et al. A Novel mutation apoE2 Kurashiki (R158P) in a patient with lipoprotein glomerulopathy. J Atheroscler Thromb. 2011;18:536–41. source
  • Findingnone given

    Hypertriglyceridemia quickly improved after treatment.

    “Hypertriglyceridemia quickly improved”
    Quote in the paperNot a substantial claim
  • Findingown data

    The patient was a 33-year-old Japanese man admitted for possible kidney disease because of massive proteinuria.

    “A 33-year-old Japanese man was admitted for possible kidney disease because of massive proteinuria.”
    Quote in the paperNot a substantial claim
  • Findingown data

    Direct DNA sequencing analyses for apo E identified a duplication of amino acid 151, aspartic acid.

    “Direct DNA sequencing analyses for apo E identified a duplication of amino acid 151, aspartic acid”
    • Also stated in: § Result · plain
      “The heterozygous mutation, Asp151 dup, p.Asp169 dup, was detected by DNA sequencing of exons 3 and 4 of the APOE gene (Fig. 2b).”
    Quote in the paperSubstantial claim
  • Findingown data

    Proteinuria decreased from about 3 g/gCr to around 1.0 g/gCr after 3 years.

    “Proteinuria decreased from about 3 g/ gCr to around 1.0 g/gCr after 3 years.”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim. 8
  • May combine two claims. 3
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Some etiology studies using APOE Sendai suggest that reduced receptor-binding activity and thermodynamic abnormalities may play important roles in the pathogenesis of LPG.

    “Some etiology studies using APOE Sendai suggest that the reduced receptor-binding activity [12] and thermodynamic abnormalities [13] may play important roles in the pathogenesis of LPG.”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites [12] Hoffmann MM, Scharnagl H, Panagiotou E, et al. Diminished LDL receptor and high heparin binding of apolipoprotein E2 Sendai associated with lipoprotein glomerulopathy. J Am Soc Nephrol. 2001;12:524–30. source
    • cites [13] Georgiadou D, Stamatakis K, Efthimiadou EK, et al. Tharmodynamic and structural destabilization of apoE3 by hereditary mutations associated with the development of lipoprotein glomerulopathy. J Lipid Res. 2013;54:164–76. source
  • May combine two claims.

    Findingown data

    Renal biopsy revealed segmental proliferation in the mesangium and lipoprotein thrombi in the glomerular capillary.

    “Renal biopsy revealed segmental proliferation in the mesangium and lipoprotein thrombi in the glomerular capillary.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    The patient's serum apo E level was 4.3 mg/dL.

    “His serum apo E level was 4.3 mg/dL.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    The patient's urinary protein excretion was 4.7 g/day.

    “His urinary protein excretion rate was 4.7 g/day”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    The patient's serum triglyceride level was 266 mg/dL.

    “a triglyceride (TG) level of 266 mg/ dL”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Findingown data

    After fibrate discontinuation, urinary protein levels reached 6 g/day, leading to end-stage kidney disease a year later.

    “the administration of fibrate was discontinued; however, urinary protein levels reached 6 g/day thereafter, leading to endstage kidney disease (ESKD) a year later”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Some in-frame deletions of amino acid residues are known to have a causative role in LPG.

    “On the other hand, some in-frame deletions of amino acid residues are also known to have a causative role in LPG.”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim.

    Premisecitation

    Lipoprotein glomerulopathy (LPG) is a rare disease characterized by lipoprotein thrombi in the glomerular capillaries due to heterozygous APOE gene mutations.

    “Lipoprotein glomerulopathy (LPG) is a rare disease characterized by lipoprotein thrombi in the glomerular capillaries due to heterozygous APOE gene mutations [1].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [1] Saito T, Matsunaga A, Oikawa S. Impact of lipoprotein glomerulopathy on the relationship between lipids and renal diseases. Am J Kidney Dis. 2006;47:199–211. source
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Most APOE gene mutations causing LPG are missense mutations due to substitution of amino acid residues around the LDL receptor-binding region.

    “Most of them are missense mutations due to the substitution of amino acid residues around the low-density lipoprotein (LDL) receptor-binding region.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [2] Matsunaga A, Saito T. Apolipoprotein E mutations: a comparison between lipoprotein glomerulopathy and type III hyperlipoproteinemia. Clin Exp Nephrol. 2014;18:220–4. source
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The APOE gene mutation due to duplicated amino acid residues was included among APOE gene mutations causing LPG.

    “In addition , the APOE gene mutation due to duplicated amino acid residues was included there [2].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [2] Matsunaga A, Saito T. Apolipoprotein E mutations: a comparison between lipoprotein glomerulopathy and type III hyperlipoproteinemia. Clin Exp Nephrol. 2014;18:220–4. source
  • May combine two claims.

    Premisecitation

    APOE Leiden and APOE5 have been reported to be associated with elevated triglycerides.

    “APOE Leiden (a partial duplication of 21 nucleotides coding for seven amino acids) associated with type III hyperlipoproteinemia [5] and APOE5 (Val 135_Arg142dup) heterozygote [6] have been reported to be associated with elevated triglycerides”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [5] Havekes L, de Wit E, Leuven JG, et al. Apolipoprotein E3-Leiden. A new variant of human apolipoprotein E associated with familial type III hyperlipoproteinemia. Hum Genet. 1986;73:157–63. source
    • cites [6] Yamanouchi Y, Takano T, Hamaguchi H, Tokunaga K. A novel apolipoprotein E5 variant with a 24-bp insertion causing hyperlipidemia. J Hum Genet. 2001;46:633–9. source
11 of 11
  • The paper relies on this without support.

    High serum apo E level is characteristic of LPG.

    “the high-serum apo E level, which is characteristic of LPG, was not observed.”
1 of 1

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • The other ApoE mutations are located outside the LDLR binding region, such as ApoE Kyoto (Arg25Cys), ApoE Tsukuba (Arg114Cys), ApoE Kanto (Asp151dup), ApoE Las Vegas (Ala152Asp), ApoE Chengdu (Leu155Pro), ApoE1 (del 156-173) and ApoE Osaka/Kurashiki (Arg158Pro).

    “The other mutations are located outside the LDLR binding region, such as ApoE Kyoto (Arg25Cys),[16] ApoE Tsukuba (Arg114Cys),[23] ApoE Kanto (Asp151dup),[24] ApoE Las Vegas (Ala152Asp),[25] ApoE Chengdu (Leu155Pro),[26] ApoE1 (del 156-173)[27] and ApoE Osaka/Kurashiki (Arg158Pro).[28]”

    From A boy and his mother with lipoprotein glomerulopathy: Two case reports and literature review (2025) · cites this paper as [24]

    The Material and methods and Result sections identify APOE Kanto as Asp151dup, supporting the part of the sentence attached to this citation. The Introduction discusses mutations around the LDL receptor-binding region but does not establish that Asp151dup lies outside it. The other named variants have separate citations and are not assessed here. (LLM, conf=0.84)

    Experimental — accuracy not yet measured
  • Five variants in helix 4 that were not in the LDL receptor binding site-APOE Kanto (Asp151dupAsp), APOE Las Vegas (Ala152Asp), APOE Chengdu (Leu155Pro), APOE1 (156_173del), and APOE Osaka/Kurashiki (Arg158Pro)-were reported to cause LPG.

    “Five variants in helix 4 that were not in the LDL receptor binding site were identified (Fig.5), but were reported to cause LPG, namely, APOE Kanto (Asp151dupAsp)70, 80), APOE Las Vegas (Ala152Asp)81), APOE Chengdu (Leu155Pro)82), APOE1 (156_173del)83), and APOE Osaka/Kurashiki (Arg158Pro)84, 85).”

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Authors
Yokochi, A., Matsunaga, A., Kanemoto, K., Tominaga, N., Uda, S., & Saito, T.
Affiliations
  • Kanto Rosai Hospital (JP)
  • Fukuoka University (JP)
  • Kawasaki Municipal Tama Hospital (JP)
Corresponding author
Yokochi, Akio
Venue
CEN Case Reports
Published
2024-08-14
Volume
14
Issue
2
Pages
162-166
ISSN
2192-4449 (ISSN-L)
OpenAlex
W4401575851
Cited by
3
References
14
Citations by year
2026: 1 · 2025: 2
FWCI
0.86
Type
journal article
Language
en
Open access
Locations
  • CEN Case Reports (publishedVersion)
  • Europe PMC (PubMed Central) (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
Topics
  • Health Sciences › Medicine › Nephrology › Renal Diseases and Glomerulopathies
  • Health Sciences › Medicine › Cardiology and Cardiovascular Medicine › Lipid metabolism and disorders
  • Health Sciences › Medicine › Nephrology › Chronic Kidney Disease and Diabetes
Keywords
lipoprotein glomerulopathy, apolipoprotein E, proteinuria, hypertriglyceridemia, mesangial cell proliferation, end-stage renal disease, fibrate therapy
MeSH terms
Adult, Apolipoproteins E, Biopsy, Humans, Kidney Diseases, Kidney Failure, Chronic, Kidney Glomerulus, Male, Mutation, Proteinuria, Apolipoprotein E2

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