A 6-month-old infant presents with regression of milestones (previously smiled and tracked), abnormal startle response to sound (hyperekplexia), cherry-red spot on fundoscopy, and hypotonia. He is of Ashkenazi Jewish descent. Which lipid accumulates and in which cellular organelle?

• A Glucocerebroside accumulates in lysosomes
• B Ganglioside GM2 accumulates in lysosomes ✓
• C Sphingomyelin accumulates in lysosomes
• D Galactocerebroside accumulates in lysosomes

Explanation

This presentation is Tay-Sachs disease: regression, cherry-red spot (ganglion cells around the fovea are destroyed while the fovea appears bright red), exaggerated acoustic startle, and hypotonia in an Ashkenazi Jewish infant. Tay-Sachs is caused by deficiency of hexosaminidase A, leading to lysosomal accumulation of ganglioside GM2. Niemann-Pick disease (option C) also presents with cherry-red spot but includes hepatosplenomegaly. Gaucher's disease (option A) causes glucocerebroside accumulation. Krabbe disease (option D) involves galactocerebroside.

Reference: Ghai Essential Pediatrics, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.