[Answered]: # 19 A 2-day-old male newborn is brought to the…

Question # 19 A 2-day-old male newborn is brought to the physician because he became somnolent and felt cold after breastfeeding. Pregnancy and delivery were uncomplicated. He was born at 40 weeks’ gestation and weighed 3538 g (7 lb 13 oz); he currently weighs 3311 g (7 lb 5 oz). Examination shows generalized hypotonia. Serum studies show an ammonia concentration of 150 μmol/L (N < 50). Fasting serum glucose concentration is normal. Accumulation of which of the following substances is most likely involved in the pathogenesis of this patient's neurological symptoms?