Tay-Sachs disease is an inherited metabolic disease caused by the harmful buildup of lipids (fatty materials such as oils and acids) in various cells and tissues in the body. It is part of a group of genetic disorders called the GM2 gangliosidoses. Tay-Sachs and its variant form are caused by a deficiency in the enzyme hexosaminidase A. Affected children appear to develop normally until about age 6 months and then begin to show symptoms, including:
- progressive loss of mental ability,
- increased startle reflex to noise,
- progressive loss of hearing leading to deafness,
- difficulty with swallowing,
- seizures that may begin in the child's second year, and
- "cherry-red" spots in their eyes.
A much rarer form of the disorder, called late-onset Tay-Sachs disease, occurs in individuals in their twenties and early thirties and is characterized by an unsteady gait and progressive neurological deterioration.
The incidence of Tay-Sachs has been particularly high among people of Eastern European and Askhenazi Jewish descent., as well as in certain French Canadians and Louisiana Cajuns. Affected individuals and carriers of Tay-Sachs disease can be identified by a blood test that measures hexosaminidase A activity. Both parents must carry the mutated gene in order to have an affected child. In these instances, there is a 25 percent chance with each pregnancy that the child will be affected with Tay-Sachs disease. Prenatal diagnosis is available if desired. A very severe form of Tay-Sachs disease is known as Sandhoff disease, which is not limited to any ethnic group.
Presently there is no specific treatment for Tay-Sachs disease. Anticonvulsant medicine may initially control seizures. Other supportive treatment includes proper nutrition and hydration and techniques to keep the airway open. Children may eventually need a feeding tube.
Even with the best of care, children with Tay-Sachs disease usually die by age 4, from recurring infection.
Research funded by the National Institute of Neurological Disorders and Stroke (NINDS) focuses on a better understanding of how neurological deficits arise in lipid storage diseases and on the development of new treatments targeting disease mechanisms. Specific research on the gangliosidoses including expanding the use of gene therapy delivered using a safe adeno-associated virus (AAV) to a larger area of the brain using an animal model of Tay-Sachs and Sandhoff diseases. A related project will study the effectiveness of whole-body AAV therapy in treating the disease. NINDS also supports the Lysosomal Diseases Network, which addresses some of the major challenges in the diagnosis, management, and therapy of rare diseases, including the lipid storage diseases.
Information from the National Library of Medicine’s MedlinePlus