Genetics, Dysmorphology, and Long-Term Outcomes
Dysmorphology is a descriptive discipline
A careful exam documents minor anomalies, growth parameters, and family history. Common syndromes have recognizable patterns: trisomy 21 (hypotonia, upslanting palpebral fissures, duodenal atresia), trisomy 18 (clenched hands, rocker-bottom feet), trisomy 13 (cleft lip, polydactyly), Turner syndrome (lymphedema, coarctation), and DiGeorge syndrome (hypocalcemia, conotruncal heart disease). Chromosomal microarray is first-line for developmental delay and multiple anomalies; whole-exome sequencing is used when a single-gene disorder is suspected. Genetic counseling addresses recurrence risk and prognosis.
Traps: overdiagnosing a syndrome from a single feature; missing that a dysmorphic infant may have feeding or airway problems; and forgetting that normal newborn screening does not exclude all metabolic disorders.
Worked example: a newborn has hypotonia, a single palmar crease, and a duodenal atresia. Karyotype confirms trisomy 21. The team counsels the family and screens for congenital heart disease and thyroid disease.
Rule of thumb: “Describe before you diagnose; pursue microarray when anomalies are multiple or development is delayed.”