Definition:
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Niemann–Pick Disease is a rare, inherited lysosomal storage disorder characterized by an abnormal accumulation of sphingomyelin, cholesterol, and other lipids in various organs, notably affecting the liver, spleen, lungs, bone marrow, and central nervous system.
Classification:
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Type A: Severe infantile form, characterized by profound neurological deterioration.
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Type B: Chronic visceral form, less severe neurological involvement.
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Type C (NPC): Distinct metabolic disorder marked primarily by abnormal cholesterol trafficking and progressive neurological impairment.
Etiology and Genetics:
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Types A and B: Caused by mutations in the SMPD1 gene on chromosome 11p15.4, leading to acid sphingomyelinase enzyme deficiency.
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Type C: Linked to mutations in NPC1 (95% cases) or NPC2 genes, disrupting cholesterol trafficking in cells.
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Autosomal recessive inheritance pattern.
Clinical Features:
