Review Question - QID 109134

A 6-month-old boy is brought to the pediatrician by his parents for a routine visit. His parents report that he is feeding and stooling well and they have just started experimenting with solid foods. His parents are concerned because a few weeks ago he started rolling from back to front in addition to front to back, but he now struggles when placed on his back. The patient was noted to be developmentally appropriate for his age at his last visit 2 months ago. On physical exam, the patient seems well-nourished and has no dysmorphic features. His temperature is 98.6°F (37°C), blood pressure is 77/49 mmHg, pulse is 112/min, and respirations are 24/min. In the examination room, he is able to roll from front to back but cannot roll from back to front. He is not able to sit without support and makes no attempt at bouncing when supported in a standing position. The patient’s abdomen is non-tender and soft without hepatosplenomegaly. His patellar reflexes are 4+ bilaterally. He is found to have the ocular finding seen in Figure A. Accumulation of which of the following would most likely be found in this patient’s cells?