Tay-Sachs disease — RACP Paediatrics MCQ

Instant feedback + full explanation. One question, done properly.

ModerateGeneticsTay-Sachs diseaseRACP Paediatrics

A 6-month-old presents with progressive hypotonia, exaggerated startle response, developmental regression, and a cherry-red spot on fundoscopy. No hepatosplenomegaly. Head circumference is increasing. What is the most likely diagnosis?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: E — Tay-Sachs disease

Hypotonia, exaggerated startle response (hyperacusis), developmental regression, cherry-red macular spot, and macrocephaly without organomegaly in an Ashkenazi Jewish infant is classic Tay-Sachs disease (hexosaminidase A deficiency, GM2 gangliosidosis). It is uniformly fatal in the infantile form. Carrier screening is available for at-risk populations.

Reference: RACP Paediatric Curriculum – Metabolic/Genetics; RCH Melbourne – 2023