The gangliosidoses are a group of inherited metabolic diseases caused by a deficiency of the different proteins needed to break down fatty substances called lipids. Excess lipid materials build up to harmful levels in the central and peripheral nervous systems, particularly in nerve cells. These genetically different disorders occur when both parents pass along the same mutated gene that regulates these proteins.The GM1 gangliosidoses are caused by a deficiency of the enzyme beta-galactosidase. Signs of early infantile GM1 gangliodisosis (the most severe subtype, with onset shortly after birth) may include neurodegeneration, seizures, liver and spleen enlargement, coarsening of facial features, skeletal irregularities, joint stiffness, distended abdomen, muscle weakness, exaggerated startle response, and problems with gait. About half of affected persons develop cherry-red spots in the eye. Children may be deaf and blind by age 1. Onset of late infantile GM1 gangliosidosisis typically between ages 1 and 3 years. Signs include ataxia, seizures, dementia, and difficulties with speech. Adult GM1 gangliosidosis strikes between ages 3 and 30, with symptoms that include muscle atrophy, corneal clouding in some patients, and dystonia. Non-cancerous skin blemishes may develop on the lower part of the trunk of the body. Adult GM1 is usually less severe and progresses more slowly than other forms of the disorder.The GM2 gangliosidoses include Tay-Sachs disease and its more severe form, called Sandhoff disease, both of which result from a deficiency of the enzyme beta-hexosaminidase. Symptoms begin by age 6 months and include progressive mental deterioration, cherry-red spots in the retina, marked startle reflex, and seizures. Children with Tay-Sachs may also have dementia, progressive loss of hearing, some paralysis, and difficulty in swallowing that may require a feeding tube. A rarer form of the disorder, which occurs in patients in their twenties and early thirties, is characterized by an unsteady gait and progressive neurological deterioration. Additional signs of Sandhoff disease include motor weakness, early blindness, spasticity, muscle contractions, an abnormally enlarged head, heart murmurs, doll-like facial features, and an enlarged liver and spleen.
No specific treatment exists for the gangliosidoses. Anticonvulsants may initially control seizures. Other supportive treatment includes proper nutrition and hydration and keeping the airway open.
Children with early infantile GM1 often die by age 3 from cardiac complications or pneumonia. Children with the early-onset form of Tay-Sachs disease often die by age 4 from recurring infection. Children with Sandhoff disease generally die by age 3 from respiratory infections.
The National Institute of Neurological Disorders and Stroke (NINDS), a part of the National Institutes of Health (NIH), conducts research on the lipid storage disorders and also supports additional research through grants to medical institutions across the country. Scientists are studying the mechanisms by which the lipids accumulating in these disorders cause harm to the body. Investigators also hope to identify biomarkers (signs that may indicate risk of a disease and aid in diagnosis) in order to speed the development of therapeutics for these disorders.The National Library of Medicine (NLM), a component of the National Institutes of Health (NIH) within the U.S. Department of Health and Human Services, offers free searches of biomedical literature through an Internet service called PubMed. Go to: www.ncbi.nlm.nih.gov/PubMed. The NLM also offers extensive health information from NIH and other trusted sources. Go to: www.medlineplus.gov.
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National Tay-Sachs and Allied Diseases Association
The mission of the National Tay-Sachs & Allied Diseases Association is to lead the fight to treat and cure Tay-Sachs, Canavan and related genetic diseases and to support affected families and individuals in leading fuller lives.
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