USMLE® Step 1 style questions USMLE
A 1-day newborn male infant is admitted into neonatal intensive care unit because of severe developmental anomalies. The baby was prematurely born to a gravida 1, para 0, mother via cesarean section following a pregnancy complicated by polyhydramnios. Upon further interrogation with the mother, she denies any hereditary disorders in the family. A physical exam shows an abdominal wall defect in which the intestines and liver are exposed (enclosed in visceral peritoneum) and an unusually large tongue. An abdominal ultrasound shows hydronephrosis and a hyperechoic left-kidney mass. His temperature is 36.7°C (98°F), pulse is 130/min, respirations are 30/min, blood pressure is 110/70 mmHg, weight is 5 kilograms (11 lb), and pulse oximetry on room air shows an oxygen saturation of 93%. Which of the following is the most likely diagnosis?