Health Supervision for Children and Adolescents With Down Syndrome

Abstract

This clinical report is designed to assist the pediatrician in caring for the child, adolescent, and family in whom a diagnosis of Down syndrome has been confirmed by chromosome analysis or suspected by prenatal screening. Although a pediatrician’s initial contact with the child is usually during infancy, occasionally the pregnant woman who has been given a prenatal diagnosis of Down syndrome will be referred for review of the condition and genetic counseling; this report offers guidance for this situation, as well. Age-specific guidance for the clinician is provided in Supplemental Fig 1.Pediatricians play an important role in the care of children and adolescents with Down syndrome and their families. Down syndrome is the most common chromosomal cause of intellectual disability, and there has been a significant improvement in quality of life for affected people. Awareness of the issues important to affected children, adolescents, and their caregivers can make a great difference in outcomes across the lifespan.Children with Down syndrome may have many cooccurring medical conditions and cognitive impairment because of the presence of extra genetic material from chromosome 21 (Table 1).1,2 Although the phenotype is variable, there typically are multiple features that enable the experienced clinician to suspect the diagnosis. Among the more common physical findings are hypotonia, small brachycephalic head, epicanthal folds, flat nasal bridge, upward-slanting palpebral fissures, Brushfield spots, small mouth, small ears, excessive skin at the nape of the neck, single transverse palmar crease, short fifth finger with clinodactyly, and wide spacing between the first and second toes, often with a deep plantar groove. The degree of cognitive impairment is variable and may be mild (IQ of 50–70), usually is moderate (IQ of 35–50), or occasionally is severe (IQ of 20–35).Medical conditions common in children with Down syndrome include hearing loss (75%), obstructive sleep apnea (50%–79%), otitis media (50%–70%), eye problems (60%–80%), including cataracts (<1%–3%),3 nasolacrimal duct obstruction (3%–36%), and strabismus and severe refractive errors (36%–80%), congenital heart defects (50%), neurologic dysfunction (1%–13%), gastrointestinal atresia (12%), hip dislocation and hip abnormalities (2%–8%),4,5 symptomatic atlantoaxial instability (1%–2%),6,7 thyroid disease (24%–50%)2,8 and, less commonly, transient abnormal myelopoiesis (4%–10%) and later leukemia (1%), autoimmune diseases,2,8–10 including Hashimoto thyroiditis (13%–39%), with incidence dependent on age, celiac disease (1%–5%), Hirschsprung disease (<1%),3 and autism (7%–19%).11,12People with Down syndrome often function more effectively in social situations than would be predicted based on cognitive assessment results, unless there is presence of cooccurring autism. Although the level of social–emotional functioning may vary, these skills may be improved with early intervention and therapy through early adulthood.In ∼96% of children with Down syndrome, the condition is sporadic because of nonfamilial trisomy 21, in which there are 47 chromosomes with the presence of a free extra chromosome 21. In ∼3% to 4% of people with the Down syndrome phenotype, the extra chromosomal material is the result of an unbalanced translocation between chromosome 21 and another acrocentric chromosome, usually chromosome 14 or 21. Approximately three-quarters of these unbalanced translocations are de novo, and the remainder result from translocation inherited from a parent. If the child has a translocation, the parents should be offered a karyotype to determine whether the translocation is familial or de novo. In the remaining 1% to 2% of people with the Down syndrome phenotype, a mix of 2 cell lines is present: 1 normal and the other with trisomy 21. This condition is called mosaicism. People with mosaicism may be more mildly affected than people with complete trisomy 21 or translocation chromosome 21, but this is not always the case, and their condition may include any of the associated medical problems and may be indistinguishable from trisomy 21. The chance of recurrence for families with an affected child depends on many factors and vary greatly, from 1% in most families to 100% in some circumstances. Table 2 describes the different chromosomal characteristics of Down syndrome.Formal counseling by a clinical geneticist or genetic counselor is recommended for all families.Several areas require ongoing assessment throughout childhood and should be reviewed at every health supervision visit and at least annually. These areas include: personal support available to family;participation in a family-centered medical home;age-specific Down syndrome-related medical and developmental conditions;financial and medical support programs and long-term financial planning for which the child and family may be eligible;injury and abuse prevention, with special consideration of developmental