Case 1: A Term Male Infant with Hypoglycemia and Hyperbilirubinemia as Initial Presentation

Abstract

A white male infant is born at term via spontaneous vaginal delivery to a 28-year-old woman at an outside facility. The parents do not have a consanguineous relationship, and the mother has had no pregnancy or delivery complications. The neonate weighs 3,170 g (11th–25th percentile), with a head circumference of 33.5 cm (4th–10th percentile) and length of 54.5 cm (76th–90th percentile). His skin is pale and multiple cafe-au-lait spots are found on his torso and extremities. He has micrognathia with an elongated head shape, a prominent occiput, and a flat anterior fontanelle. He is admitted to the NICU for hypoglycemia and receives antibiotics for 48 hours while sepsis is ruled out. Herpes simplex virus, cytomegalovirus, and peripheral blood cultures are negative. He continues to have refractory hypoglycemia and further tests reveal significant elevated γ-glutamyl transpeptidase (GGT) relative to mildly elevated aspartate aminotransferase (AST) and alanine aminotransferase (ALT), elevated direct hyperbilirubinemia, and mildly prolonged coagulation studies. Abdominal ultrasonography findings are normal. At 6 days of age, he begins to feed poorly so a nasogastric tube is placed for enteral feeds. The following day he is transferred to our facility for specialty consultation because of persistent hyperbilirubinemia and significantly elevated GGT. Upon admission to our unit he is noted to be an alert, active infant with normal male genitalia, but has bronze-colored skin and a large anterior fontanelle. His laboratory findings on admission reveal the following: sodium, 136 mEq/L (136 mmol/L); potassium, 6.9 mEq/L (6 mmol/L); chloride, 19 mEq/L (19 mmol/L); AST, 138 U/L (2.3 μkat/L); ALT, 97 U/L (1.6 μkat/L); …