Question

A child presents with mental retardation, bone pain, and inability to walk. On funduscopic examination, a cherry red spot is seen. There is no organomegaly. What is the most likely diagnosis?

• A. Tay-Sachs disease
• B. Niemann-Pick disease
• C. Hurler syndrome
• D. Gaucher disease

Answer 1

The Correct Option is A

Tay-Sachs disease is the most likely diagnosis for the child described in the scenario. This disorder typically presents with mental retardation, bone pain, and inability to walk. A key diagnostic feature is the presence of a cherry-red spot on funduscopic examination, and importantly, this disease is characterized by the absence of organomegaly.

Let's break down the clues:

• Mental Retardation: Seen in several lysosomal storage disorders, including Tay-Sachs.
• Bone Pain and Inability to Walk: Neuromuscular symptoms are common in Tay-Sachs due to progressive central nervous system deterioration.
• Cherry Red Spot: A hallmark of Tay-Sachs is the cherry-red spot observed during funduscopic examination. This occurs due to the accumulation of gangliosides in the retinal ganglion cells.
• Absence of Organomegaly: Tay-Sachs disease is differentiated from Niemann-Pick and Gaucher disease, which typically include hepatosplenomegaly as a symptom.

Given these points, Tay-Sachs disease stands out as the most suitable diagnosis. This disease is caused by a deficiency of the enzyme hexosaminidase A, leading to an accumulation of GM2 ganglioside, particularly affecting the nervous system.

Feature	Tay-Sachs	Niemann-Pick	Hurler	Gaucher
Mental Retardation	Yes	Yes	Yes	Variable
Bone Pain	Yes	Variable	Yes	Yes
Inability to Walk	Yes	Possible	Possible	Possible
Cherry Red Spot	Yes	Possible	No	No
Organomegaly	No	Yes	Yes	Yes

Conclusion: The absence of organomegaly and presence of a cherry-red spot strongly indicate Tay-Sachs disease as the correct diagnosis.