1. A 1.5-year-old boy is being evaluated for a large head size. He was born at 38 weeks gestation following an uneventful pregnancy. He was reportedly normal at birth and in the first few months of life, but subsequent measurements of head circumference noted an increase. His current head circumference is above the 97th percentile. He is otherwise meeting age-appropriate milestones, and there are no syndromic concerns. Based on this information, what is the most likely diagnosis and the appropriate next step?
What do you think is the underlying cause?
2. A 6-year-old Caucasian boy presents to the office for evaluation of developmental delay. He was born full-term following an unremarkable pregnancy but remained in the hospital for 2 days due to feeding difficulties and jaundice. His birth weight was 7 lbs. 8 oz. (25-50th percentile) and length was 22 in. (>95th percentile). On examination, he is noted to be tall and macrocephalic (both >97th percentile) with mild craniofacial abnormalities. His hands and feet are enlarged. Neurologic examination is non-focal. The family history is non-contributory regarding similarly affected individuals. Based on the above, what is the most likely diagnosis and the appropriate next step?
