Genetic Disorders · NEET PG Preparation Paediatrics
A 6-month-old infant is brought to the pediatrician for developmental regression, hypotonia, and an exaggerated startle response to sudden noises. Fu…
Practice question from Genetic Disorders (NEET PG Preparation Paediatrics), with the correct answer and a step-by-step solution.
medium · MCQ · Q-1D7469
A 6-month-old infant is brought to the pediatrician for developmental regression, hypotonia, and an exaggerated startle response to sudden noises. Fundoscopic examination reveals a cherry-red spot in the macula. Hepatosplenomegaly is notably absent. Which of the following is the most likely underlying biochemical defect?
- A.Glucocerebrosidase deficiency
- B.Hexosaminidase A deficiencyCorrect answer
- C.Sphingomyelinase deficiency
- D.Alpha-galactosidase A deficiency
Solution
Tay-Sachs disease is an autosomal recessive lysosomal storage disorder caused by a deficiency of hexosaminidase A, leading to the accumulation of GM2 ganglioside in neurons. It presents around 6 months of age with developmental regression, hypotonia, a hyper-reactivity to noise (exaggerated startle), and a characteristic cherry-red spot on the macula. Unlike Niemann-Pick disease (sphingomyelinase deficiency), hepatosplenomegaly is absent in Tay-Sachs.
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