Introduction
- Rare autosomal recessive lipid storage disease.
- Abnormal cholestanol accumulation in the nervous system and other organ systems.
- Clinical manifestations: Brain, tendons, eyes, arteries.
- Spectrum of presentations: Infantile diarrhea, cataracts, tendon xanthomas, progressive neurologic impairments.
- Neurologic manifestations: Ataxia, dystonia, epilepsy, dementia, etc.
- Diagnostic delay: Median of 16 years.
- Early intervention with chenodeoxycholic acid (CDCA) critical for prognosis.
Etiology
- Mutation in CYP27A1 gene encoding sterol 27-hydroxylase.
- Defective bile acid synthesis → Accumulation of cholestanol.
- Impacts cholesterol conversion → Multi-organ involvement.
Epidemiology
- Rare, underdiagnosed condition.
- Global prevalence estimates:
- U.S.: ~1 in 72,000 to 1 in 150,000.
- Higher prevalence in South Asians and East Asians.
Histopathology
- Tendon histology: Foamy histiocytes, multinucleated giant cells, cholesterol clefts.
- Brain findings: Demyelination, neuronal loss, lipid clefts, reactive astrocytosis.
- Peripheral nerves: Axonal degeneration.
Clinical Presentation
Key Symptoms by Age