These guidelines are designed to assist the pediatrician in caring for the child in whom the diagnosis of Down syndrome has been confirmed by karyotype. Although the pediatrician's initial contact with the child is usually during infancy, occasionally the pregnant woman who has been given the prenatal diagnosis of Down syndrome will be referred for advice. Therefore, these guidelines offer advice for this situation as well.

Children with Down syndrome have multiple malformations and mental retardation due to the presence of extra genetic material from chromosome 21. Although the phenotype is variable, usually there is enough consistency to enable the experienced clinician to suspect the diagnosis. Among the more common physical features are hypotonia, small brachycephalic head, epicanthic folds, flat nasal bridge, upward slanting palpebral fissures, Brushfield spots, small mouth, small ears, excess skin at the nape of the neck, single transverse palmar crease, and short fifth finger with clinodactyly. A wide space, often with a deep fissure, between the first and second toes is also common. The degree of mental retardation is variable, ranging from mild (IQ, 50 to 70) to moderate (IQ, 35 to 50), and only occasionally to severe (IQ, 20 to 35). There is an increased risk of congenital heart disease (50%); leukemia (<1%); deafness (75%); serous otitis media (50% to 70%); Hirschsprung disease (<1%); gastrointestinal atresias (12%); eye disease (60%), including cataracts (15%) and severe refractive errors (50%); acquired hip dislocation (6%); and thyroid disease (15%). Social quotient may be improved with early intervention techniques. Although level of function is exceedingly variable, children with Down syndrome often function better in social situations than might be expected from their IQ.

In about 95% of children with Down syndrome, the condition is due to nonfamilial trisomy 21. In approximately 3% to 4% of individuals with the Down syndrome phenotype, the extra chromosomal material is the result of an unbalanced translocation between chromosome 21 and another acrocentric chromosome. About three fourths of these unbalanced translocations are de novo, and about one fourth are the result of familial translocations. If the child has a translocation, a balanced translocation must be excluded in the parents. If there is a translocation in either parent, additional familial studies and counseling should be instituted. In the remaining 1% to 2% of individuals with the Down syndrome phenotype, two cell lines are present: one normal and one trisomy 21. This condition is called mosaicism. These individuals, on average, are affected less severely than individuals with trisomy 21 or translocated chromosome 21.

Medical management, home environment, education, and vocational training can significantly affect the level of functioning of children and adolescents with Down syndrome and facilitate their transition to adulthood. The following outline is designed to help the pediatrician in caring for children with Down syndrome and their families.[1,2] It is organized by the issues that need to be addressed in the various age groups.

Several areas require ongoing assessment throughout childhood and should be reviewed periodically at developmentally appropriate ages. These include the following:

• Review personal support available to family.
• Periodically review all the other financial and medical support programs for which the child and family may be eligible.
• Discuss filing for Supplemental Security Income (SSI) benefits.
• Discuss injury prevention with special consideration of developmental skills.
• Discuss diet and exercise to maintain appropriate weight.

THE PRENATAL VISIT Pediatricians may be asked to counsel a family in which a fetus has a genetic disorder. In some settings, the pediatrician may be the primary resource for counseling. At other times, counseling may already have been provided for the family by a clinical geneticist and/or obstetrician. Because of a previous relationship with the family, however, the pediatrician may be called on to review this information and to assist in the decision-making process. As appropriate, the pediatrician should cover the following topics with the family:

1. Review and demonstrate the laboratory or imaging studies leading to the diagnosis.
2. Explain the mechanism for occurrence of the disease in the fetus and the potential recurrence rate for the family.
3. Review the prognosis and manifestations, including any variability.
4. When applicable, recommend further studies that may refine the estimation of the prognosis (eg, fetal echocardiogram).
5. Review the currently available treatments and interventions. This discussion needs to include the efficacy, potential complications and/or side effects, costs, or other burdens of these treatments. Discuss any plausible future treatments.
6. Explore the options available to the family for management and rearing of the child using a nondirective approach. In cases of early prenatal diagnosis, this may include discussion of pregnancy continuation or termination, rearing the child at home, foster care placement, adoption, etc.

If the pregnancy is continued, a plan for delivery and neonatal care must be developed with the obstetrician and the family. As the pregnancy progresses, further studies may be of value in modifying this management plan (eg, detection of a complex heart defect by echocardiography). When appropriate, referral to a clinical geneticist should be considered for a more extended discussion of recurrence rates, future reproductive options, and evaluation of the risks of other family members.

HEALTH SUPERVISION FROM BIRTH TO 1 MONTH: NEWBORNS

Examination

Confirm the diagnosis of Down syndrome and review the karyotype with the parents. Review the phenotype. Discuss the specific findings with both parents whenever possible, and talk about the following potential clinical manifestations associated with the syndrome. These may have to be reviewed again at a subsequent meeting.

• Feeding problems.
• Hypotonia.
• Facial appearance.
• Check for strabismus, cataracts, and nystagmus at birth or by 6 months.
• Heart defects (~50% risk). Perform cardiac evaluation (echocardiogram recommended).
• Duodenal atresia.
• Leukemia--more common in children with Down syndrome than in the general population, but still rare (<1%); leukemoid reactions, on the other hand, are common.
• Congenital hypothyroidism (1% risk).
• Increased susceptibility to respiratory tract infections.

Anticipatory Guidance

Discuss the availability and efficacy of early intervention.

• Discuss the early intervention services in the community.
• Inform the family of the availability of support and advice from the parents of other children with Down syndrome.
• Supply names of Down syndrome support groups and current books and pamphlets. (See "Bibliography and Resources for New Parents.")

Discuss the strengths of the child and positive family experiences.

• Check on individual resources for support, such as family, clergy, and friends.
• Talk about how and what to tell other family members and friends. Review methods of coping with long-term disabilities.

Review the prenatal diagnosis and recurrence risk in subsequent pregnancies.

• Trisomy 21 has a recurrence risk of 1 in 100 until maternal age 35, when age-determined risks take precedence. Other family members do not have an increased risk of bearing children with abnormal chromosomes.
• Recurrence risk assessment in translocations is more complex; the pediatrician should consult a genetics specialist in such cases.
• Discuss unproven therapies.[3]

HEALTH SUPERVISION FROM 1 MONTH TO 1 YEAR: INFANCY

Examination

Physical examination and laboratory studies.

• Monitor the infant's hearing at each health supervision visit and review the risk of serous otitis media (~50% to 70%).[4] Use developmentally appropriate subjective and objective criteria. Refer the infant to an audiologist if necessary.
• Check for strabismus, cataracts, and nystagmus by 6 months, if not done at birth. At 6 to 12 months, check the infant's vision at each visit, using developmentally appropriate subjective and objective criteria. Refer the infant to an ophthalmologist if necessary by 9 months.
• Perform thyroid screening tests. Repeat at 4 to 6 months and at 12 months.[5]

Anticipatory Guidance