system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
An 7-month-old boy is brought to the pediatrician by his parents due to progressively worsening weakness for the last three months. The parents also describe the boy as having an exaggerated response when startled as well as diminishing response to visual stimuli. At birth, the boy was healthy and remained as such for the first few months of life. The mother says pregnancy was unremarkable, and the boy was born at 39 weeks with no complications during delivery. He is up to date on his vaccinations. The boy's grandparents immigrated from an eastern European country. Physical examination reveals hyperreflexia. Abdominal examination reveals no abnormalities. On fundoscopy, the following is seen. Which of the following is most likely deficient in this patient?
assistant
Hexosaminidase A