Sialidosis I. Cherry-red spot myoclonus syndrome (CRSMS)
Incidence
It is a sialidase (alpha-neuraminidase) deficiency. AR disease.
Clinical Characteristics
Usually start in late childhood or adolescence. It is characterized by progressive visual loss, polymyoclonus and seizures (generalized TC) . Action and intention myoclonus is the landmark of the disease, associated with retinal cherry-red spot. Ataxia has been reported. Normal intelligence but later decline. No dysmorphism. Symptoms start in late childhood to adulthood. Slow clinical progression. Blindness and optic atrophy occur in late stages of the disease. Vacuolated lymphocytes in peripheral smear.
Precipitants
no
Provocation Tests
Testing for intention tremor, reaching for an object, etc.
Diagnostic Procedures
EB(F). In urine thin layer chromatography (TLC) looking for sialic acid containing oligosaccharides.