Factsheet
Condition:
Tay-Sachs disease
Inheritance:
Autosomal recessive
Genetic Etiology:
Mutation in HEXA gene, which encodes beta-hexosaminidase, alpha chain.
Frequency:
1/3,600 in Ashkenazi Jews; increased frequency also in French Canadians and Old Order Amish
Clinical features:
The acute infantile form presents with neurological deterioration beginning around 3 months of age. There are myoclonic jerks and an enhanced startle reaction is noted. There is gradual enlargement of head size and development of a cherry-red spot in the macula of the eye. Most die between 2-4 years of age. Milder forms may present in later childhood, though progression to death still occurs. An adult-onset form presents primarily with motor symptoms.
Management:
Supportive care.
Genetic counseling:
Based on autosomal recessive inheritance; diagnosis of carrier status may be done by enzyme assay or molecular genetic testing. Carrier screening programs in high risk populations have reduced the incidence of the disease.