Contents
Rare disorder of sphingolipid metabolism, related to a genetic deficiency of the enzyme β-hexosaminidase.
- Autosomal recessive inheritance
Clinical features
Classical infantile variant:
Onset at 3-9 months of age, following initial normal development
- Regression of milestones
- Muscular hypotonia
- Startle response followed by spastic quadriparesis
- Seizures
- Macular cherry red spots (non-specific finding)
Rapid progression of disease with death occurring by 3–5 years of age
Juvenile/subacute variant
Seen in 2-5 years of age
- Dementia
- Cerebellar ataxia
- Mental retardation
- Spinal muscular atrophy
Adult/chronic variant
Seen in second or third decade
- Presentation varies widely from spinocerebellar degeneration to motor neuron disorders
Diagnosis
- Hexosaminidases A, B, and AB level detection
- Bilateral thalamic involvement