Assays / Genetic Enzymes / Tay-Sachs Disease

Presentation is usually at six months of age when affected infants, who previously have appeared normal and passed their early milestones, become lethargic, floppy and poor feeders. They show an abnormal accentuated startle response to sudden noises. There is usually a macular cherry-red spot. Motor development becomes progressively retarded and as the disease progresses blindness, spasticity and decerebrate rigidity occur. Feeding becomes increasingly difficult and death usually occurs by 3 years following pulmonary infection. Later onset forms of the disease with juvenile or adult presentation and sub-acute or chronic courses also occur. In these there may be survival into adolescence, or longer survival with normal intelligence but slowly progressive spinocerebellar degeneration.

Enzyme Test: b-Hexosaminidase A is measured for diagnosis of this disease.

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