A 4 1/2 year-old Hispanic boy is referred to the pediatric clinic because of failure to thrive and growth retardation. He was born at full-term in Mexico and weighed 1.9 kg at birth (lower than the 3rd percentile). He was hospitalized for 1 week immediately after birth because of feeding concerns. His mother reports that he has always been small and has had difficulty in gaining weight. His height and weight are both lower than the 3rd percentile for his age. He has developmental delays in his gross motor and verbal skills.
Physical examination reveals a quiet, small, thin boy. He weighs 12.2 kg (lower than the 3rd percentile) and is 95.3 cm tall (lower than the 3rd percentile). His occipitofrontal circumference is 48.5 cm (25th percentile) and his head appears large in relation to the rest of his body. He has a triangular-appearing face marked by a broad forehead that tapers into a hypoplastic midface with a narrow small chin. His eyes have an anti-mongoloid slant. His mouth is wide and thin with the corners downturned. He also has hemihyperplasia; the left side of his body appears larger than the right. A leg length discrepancy is evident: the right leg is shorter than the left by 3/4 of an inch. Fifth finger clinodactyly is present on both hands. A caf au lait spot is seen on his anterior chest wall.
High-resolution chromosome analysis is normal (46,XY) and results of tests for serum amino acids are negative.
TO WHAT GENETIC DISORDER DOES THIS PROFILE POINT?
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