Retina: cherry red spot in an infant: practice question

A Ophthalmology question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Ophthalmology · Retina: cherry red spot in an infant

Sample item

A 9-month-old child has an exaggerated startle to sounds, loss of earlier motor skills and hypotonia. The fovea shows a cherry red spot surrounded by pale retina. What is the underlying defect?

AHexosaminidase A deficiencyBGalactose-1-phosphate uridyl transferase deficiencyCRetinal artery occlusion by embolusDGlucocerebrosidase deficiency

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

A. Hexosaminidase A deficiency

Tay-Sachs disease from hexosaminidase A deficiency stores GM2 ganglioside in the ganglion cells, which are thickest around the fovea, so the thin foveal centre shows red against whitened retina. A cherry red spot is also seen in Niemann-Pick disease and CRAO. The infant picture with startle fits Tay-Sachs.

Option by option

A. Hexosaminidase A deficiency (correct)
Correct. Hexosaminidase A deficiency causes GM2 storage with hyperacusis and regression.
B. Galactose-1-phosphate uridyl transferase deficiency
Galactosaemia causes cataract and liver disease, not a cherry red spot.
C. Retinal artery occlusion by embolus
An embolic occlusion is a sudden painless loss in an adult, not progressive regression in an infant.
D. Glucocerebrosidase deficiency
Glucocerebrosidase deficiency causes Gaucher disease without a typical cherry red spot.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

Questions about this Ophthalmology question

What is the answer to this Ophthalmology question?

The best answer is A, Hexosaminidase A deficiency. Tay-Sachs disease from hexosaminidase A deficiency stores GM2 ganglioside in the ganglion cells, which are thickest around the fovea, so the thin foveal centre shows red against whitened retina.

Why is "Galactose-1-phosphate uridyl transferase deficiency" not the answer?

Galactosaemia causes cataract and liver disease, not a cherry red spot.

Why is "Retinal artery occlusion by embolus" not the answer?

An embolic occlusion is a sudden painless loss in an adult, not progressive regression in an infant.

Why is "Glucocerebrosidase deficiency" not the answer?

Glucocerebrosidase deficiency causes Gaucher disease without a typical cherry red spot.

What concept does this question test?

It tests Retina: cherry red spot in an infant in Ophthalmology. A cherry red spot is also seen in Niemann-Pick disease and CRAO. The infant picture with startle fits Tay-Sachs.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Retina: cherry red spot in an infant?

Group the red eye by what to examine and what the pupil does. Then use the flashcards and the other Ophthalmology questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.