Overview
Definition
A group of autosomal recessive lysosomal storage disorders characterized by sphingomyelinase deficiency (Types A/B) or impaired lipid trafficking (Type C).
Epidemiology
Rare, Type A is highly lethal in early infancy.
Etiology & Risk Factors
- SMPD1 mutations (Types A/B) or NPC1/NPC2 mutations (Type C)
Clinical Symptoms
- Hepatosplenomegaly
- Progressive neurological regression
- Cherry-red spot on macula (Type A)
- Vertical supranuclear gaze palsy (Type C)
Clinical Approach
Diagnosis
- Acid sphingomyelinase activity (Types A/B)
- Filipin staining of skin fibroblasts (Type C)
- Genetic testing
Management
- Symptomatic care
- Miglustat for neurological symptoms in Type C
Complications
- Severe developmental delay / Dementia
- Respiratory failure
- Hepatic failure