What are the symptoms of Tay-Sachs and Sandhoff diseases?
Babies with the classic (infantile) forms of Tay-Sachs and Sandhoff diseases appear healthy at birth and seem to develop normally for the first few months of life. Symptoms generally appear by about 6 months of age when an apparently healthy baby gradually stops smiling, crawling, turning over and reaching out. The baby continues to lose skills gradually and eventually becomes blind, paralyzed and unaware of surroundings. Babies with Tay-Sachs disease usually die by age 5, and those with Sandhoff disease by age 3 (1, 2). What causes the symptoms of these diseases? Babies with classic Tay-Sachs and Sandhoff diseases lack an enzyme (protein) called hexosaminidase. There are two versions of this enzyme, hex A and hex B. Babies with Tay-Sachs disease do not make hex A, and babies with Sandhoff do not make either hex A or hex B. A small number of babies with Tay-Sachs disease (AB variant) make both versions of the enzyme, but lack another protein that is needed for these enzymes to work pro
