A 3-MONTH-OLD infant, the second child of nonconsanguinous parents, was born by spontaneous vaginal delivery at 37 weeks' gestation weighing 3350 g (75th percentile). Maternal exposure to drugs or alcohol during pregnancy was denied. Polyhydramnios was noted at 20 weeks' gestation. The infant had feeding difficulties and became emaciated. By 3 months, her weight had fallen to 3070 g and her head circumference was 36.6 cm, both less than the third percentile. The infant had a dysmorphic appearance with coarse features, including depressed nasal bridge, full lips, and posteriorly rotated and thickened auricles (Figure 1). Her scalp hair was sparse and curly. A flame nevus was present on the glabella, and the skin of the forehead was wrinkled. Macroglossia was present. Her cry was coarse. Loose skin was noted over the neck, in the axillae, and on the arms (Figure 2). The nipples were hyperplastic. A grade 3/6 blowing systolic murmur was heard on cardiac examination. The palms and soles had deep skin creases (Figure 3).
Echocardiographic study demonstrated a perimembranous ventricular septal defect. Markedly prolonged gastric emptying time was demonstrated by radionuclide study. A study of the esophagus showed no abnormalities. Plasma amino acids, blood glucose levels, and thyroid function test results were normal. The karyotype was 46,XX. A FISH (fluorescent in situ hybridization) study with the elastin probe for Williams syndrome was negative.