A 2-year-old child presents with progressive neurological deterioration, hepatosplenomegaly, and a cherry-red spot on fundoscopy. Electron microscopy of a liver biopsy shows lysosomal storage of sphingomyelin with 'zebra bodies'. Enzyme assay confirms sphingomyelinase deficiency. The disease pattern in this child (rapid neurological decline, early death) corresponds to which type?
- A Niemann-Pick disease Type B
- B Niemann-Pick disease Type A ✓
- C Niemann-Pick disease Type C
- D Gaucher disease Type 2
Correct answer: B. Niemann-Pick disease Type A
Explanation
Niemann-Pick disease Type A is the severe infantile neuronopathic form caused by acid sphingomyelinase (SMPD1 gene) deficiency, with massive sphingomyelin accumulation in brain, liver, spleen, and lungs. It presents in infancy with hepatosplenomegaly, a cherry-red spot, and rapid psychomotor regression, with death typically by age 3. Type B has visceral disease without neurological involvement. Type C involves NPC1/NPC2 gene mutations with cholesterol trafficking defect (different biochemistry); Gaucher type 2 has glucocerebrosidase deficiency.
Reference: Ghai Essential Pediatrics, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.