$Unique_ID{BRK04255} $Pretitle{} $Title{Tay-Sachs Disease} $Subject{Tay-Sachs Disease Amaurotic Familial Idiocy Amaurotic Familial Infantile Idiocy Cerebromacular degeneration GM2 Gangliosidosis, Type 1 Hexoaminidase Alpha-Subunit Deficiency (Variant B) Infantile cerebral ganglioside Infantile sipoidosis GM-2 gangliosideoses (type S) Lipidosis, ganglioside, infantile Sphingolipidosis Sandhoff Disease Alper's Disease Kufs Disease Leighs Disease} $Volume{} $Log{} Copyright (C) 1984, 1985, 1986, 1987, 1988, 1989, 1992 National Organization for Rare Disorders, Inc. 9: Tay-Sachs Disease ** IMPORTANT ** It is possible that the main title of the article (Tay-Sachs Disease) is not the name you expected. Please check the SYNONYMS listing to find the alternate name and disorder subdivisions covered by this article. Synonyms Amaurotic Familial Idiocy Amaurotic Familial Infantile Idiocy Cerebromacular degeneration GM2 Gangliosidosis, Type 1 Hexoaminidase Alpha-Subunit Deficiency (Variant B) Infantile cerebral ganglioside Infantile sipoidosis GM-2 gangliosideoses (type S) Lipidosis, ganglioside, infantile Sphingolipidosis Information on the following diseases can be found in the Related Disorders section of this report: Sandhoff Disease Alper's Disease Kufs Disease Leighs Disease General Discussion ** REMINDER ** The Information contained in the Rare Disease Database is provided for educational purposes only. It should not be used for diagnostic or treatment purposes. If you wish to obtain more information about this disorder, please contact your personal physician and/or the agencies listed in the "Resources" section of this report. Tay-Sachs disease is a rare inherited disorder that results in the progressive destruction of the central nervous system. The body is unable to properly metabolize certain fats (lipids) due to the absence of an enzyme (hexosaminidase A). This results in the accumulation of these fats in the brain (GM2 ganliosidosis). The disease is generally found among children of East European Jewish heritage. Sandhoff disease is another form of Tay-Sachs disease that is not limited to any particular ethnic group. Symptoms Tay-Sachs disease is a rare inherited disorder that results in the progressive destruction of the central nervous system. The body is unable to properly metabolize certain fats (lipids) due to the absence of an enzyme (hexosaminidase A). This results in the abnormal accumulation of these fats in the brain (GM2 ganliosidosis). Tay-Sachs disease generally begins as mild muscle weakness with onset around 3 to 5 months of age. An abnormal startle response (a normal reflex in young infants caused by a sudden loud noise) and muscle spasms (myoclonic jerks) may also be seen at this time. Between 6 to 10 months of age further signs appear; i.e., feeding difficulties, muscle weakness (hypotonia), restlessness and vision abnormalities such as staring episodes, unusual eye movements and red circular spots in the eyes surrounded by fluid (cherry red macular spots). By the end of the first year there is increasing loss of vision. After 12 months the child begins to regress, losing learned skills and coordination. Seizures begin and deterioration continues. Eventually the child is limp (flaccid), unresponsive and paralyzed. Tay-Sachs disease can be detected prenatally through amniocentesis. Prospective parents can be tested to determine if they are carriers for the Tay-Sachs gene. Both the mother and the father must have the gene in order for a child to be affected (see "Causes"). Causes Tay-Sachs Disease is a very rare disorder inherited as an autosomal recessive genetic trait. Human traits, including the classic genetic diseases, are the product of the interaction of two genes, one received from the father and one from the mother. In recessive disorders, the condition does not appear unless a person inherits the same defective gene for the same trait from each parent. If one receives one normal gene and one gene for the disease, the person will be a carrier for the disease, but usually will not show symptoms. The risk of transmitting the disease to the children of a couple, both of whom are carriers for a recessive disorder, is twenty-five percent. Fifty percent of their children will be carriers, but healthy as described above. Twenty-five percent of their children will receive both normal genes, one from each parent, and will be genetically normal. The gene that causes Tay-Sachs and its resulting enzyme deficiency (hexoaminidase B subunit) has been located on chromosome 5. This deficiency causes excessive storage of certain fats (gangliosides) in the central nervous system. Affected Population Tay-Sachs disease primarily affects children of Eastern European Jewish ancestry (Ashkenazi). Approximately 1 in 30 Ashkenazi Jews carry the gene for Tay-Sachs Disease. It is also sometimes found in some communities of Italian descent, in Irish Catholics and in non-Jewish Canadians. Related Disorders Symptoms of the following disorders, can be similar to those of Tay-Sachs disease. Comparisons may be useful for a differential diagnosis. Sandhoff Disease is another form of Tay-Sachs disease. It is a severe, progressive, inherited, fat (lipid) storage disorder that leads to the destruction of the central nervous system. The first symptoms usually occur in the third to sixth month of life. These symptoms may include feeding problems, general tiredness (lethargy) and a marked "startle" response to sounds. Cherry red spots (macules) are usually seen in the eyes. (For more information on this disorder, choose "Sandhoff Disease" as your search term in the Rare Disease Database). Alpers Disease is a rare progressive neurological disorder affecting infants and children. It is characterized by the degeneration (deterioration) of areas of the brain (cerebral gray matter). This may result in muscle disturbances, seizures, partial paralysis, jerky muscle spasms (myoclonus), blindness and growth retardation. Unrelenting seizures and mental deterioration may occur. Liver disease may also be associated with this disorder. (For more information on this disorder, choose "Alpers Disease" as your search term on the Rare Disease Database). Kufs Disease is a very rare inherited disorder that causes an accumulation of pigmented fats in the brain (lipofuscinoses). Symptoms may include muscle weakness, lack of coordination, confusion, behavioral changes, and in some cases severe mental disturbances may occur. Kufs disease first appears in adolescents or young adults. The AB variant of Tay-Sachs disease (hexosaminidase activator deficiency) might be confused with this disorder initially. Later symptoms of Kufs disease may include large, dark, round spots on the skin (ichthyosis vulgaris). (For more information on this disorder, choose "Kufs Disease" as your search term in the Rare Disease Database). Leigh's Disease is a severe genetic metabolic disorder that is generally diagnosed in infancy. This disease causes damage to the brain, spinal cord and optic nerve. Infants may have low body weight, slow growth and seizures. There is a progressive loss of neurological function which may result in mental retardation. (For more information on this disorder, choose "Leigh's Disease" as your search term in the Rare Disease Database). Therapies: Standard The treatment of Tay-Sachs disease is symptomatic and supportive. The presence of the gene that causes Tay-Sachs disease can be detected prior to birth (prenatally) by a laboratory analysis of the fluid that surrounds the fetus (amniocentesis). Prospective parents can be tested to determine if they are carriers for this disease. Pregnancies in couples at risk (both parents carriers) can be tested by amniocentesis. Therapies: Investigational Research is ongoing for Tay-Sachs Disease. Scientists have not yet discovered a way to replace the missing enzyme in the bodies of children with this disorder. This disease entry is based upon medical information available through September 1992. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder. Resources For more information on Tay-Sachs Disease, please contact: National Organization for Rare Disorders (NORD) P.O. Box 8923 New Fairfield, CT 06812-1783 (203) 746-6518 National Tay-Sachs and Allied Diseases Association, Inc. 2001 Beacon St., Rm. 304 Brookline, MA 02164 (617) 277-4463 or 277-3965 NIH/National Institute of Child Health and Human Development (NICHD) 9000 Rockville Pike Bethesda, MD 20892 (301) 496-5133 NIH/National Institute of Neurological Disorders & Stroke (NINDS) 9000 Rockville Pike Bethesda, MD 20892 (301) 496-5751 (800) 352-9424 National Foundation for Jewish Genetic Diseases 250 Park Ave., Suite 1000 New York, NY 10177 (212) 682-5550 Tay-Sachs and Allied Diseases Association 17 Sydney Road Barkingside, Ilford Essex England 01-550-8989 Dr. Roy Gravel Montreal Children's Hospital 2300 Tupper St. Montreal PQ H3H 1P3 Canada Research Trust for Metabolic Diseases in Children Golden Gates Lodge Weston Road Crewe CW1 1XN, England (0270) 250244 For information on genetics and genetic counseling referrals, please contact: March of Dimes Birth Defects Foundation 1275 Mamaroneck Avenue White Plains, NY 10605 (914) 428-7100 Alliance of Genetic Support Groups 35 Wisconsin Circle, Suite 440 Chevy Chase, MD 20815 (800) 336-GENE (301) 652-5553 References CECIL TEXTBOOK OF MEDICINE, 18th ed.: James B. Wyngaarden, and Lloyd H. Smith, Jr., Eds.: W. B. Saunders Co., 1988. Pp. 149, 157, 174. MENDELIAN INHERITANCE IN MAN, 8th ed.: Victor A. McKusick; Johns Hopkins University Press, 1986. Pp. 1198-1201. BIOCHEMISTRY AND GENETICS OF TAY-SACHS DISEASE; Canadian Journal of Neurological Science, (Aug 1991, issue 18 (3 suppl)). Pp. 419-423.