$Unique_ID{BRK03761} $Pretitle{} $Title{Ganglioside Sialidase Deficiency} $Subject{Ganglioside Sialidase Deficiency Lipid Disorder Mucolipidosis IV ML IV Neuraminidase Deficiency ML Disorder} $Volume{} $Log{} Copyright (C) 1986, 1988, 1990 National Organization for Rare Disorders, Inc. 305: Ganglioside Sialidase Deficiency ** IMPORTANT ** It is possible the main title of the article (Ganglioside Sialidase Deficiency) is not the name you expected. Please check the SYNONYMS listing to find the alternate names and disorder subdivisions covered by this article. Synonyms Lipid Disorder Mucolipidosis IV ML IV Neuraminidase Deficiency ML Disorder 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. The Mucolipidoses are a family of hereditary disorders in which enzyme deficiencies cause both complex carbohydrates (mucopolysaccharides) and certain fatty substances (mucolipids) to accumulate in body tissues without excess mucopolysaccharides in the urine. (For more information on the Mucolipidoses, choose "ML Disorder" as your search term in the Rare Disease Database.) Symptoms Ganglioside Sialidase Deficiency is characterized by a deficiency in the enzyme ganglioside sialidase which causes abnormalities of connective tissue cells, defects of the cornea and retardation of physical and mental development. Ganglioside Sialidase Deficiency generally occurs at birth or early infancy. The first symptom usually is clouding of the eye's cornea. Retardation of physical and mental development usually does not appear until the end of the first year after which symptoms tend to progress gradually. Patients with ML IV do not have enlargement of the liver or spleen, skeletal involvement or mucopolysaccharides in the urine. Degeneration of the retina with a reduced electroretinogram (ERG) may be found in older children. Biopsies of connective tissue cells (fibroblasts) usually show abnormalities. Causes Ganglioside Sialidase Deficiency is an autosomal recessive hereditary disorder caused by a deficiency of the enzyme ganglioside sialidase, which leads to abnormalities in certain connective tissue cells (fibroblasts). (Human traits including the classic genetic diseases, are the product of the interaction of two genes for that condition, 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 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 show no 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.) Affected Population Ganglioside Sialidase Deficiency may affect children of both sexes. About one-half of the reported patients are of Ashkenazi Jewish extraction with ancestors originating from eastern Europe and in particular southern Poland. The exact incidence is unknown with less than 20 reported patients in the medical literature. Therapies: Standard Treatment of Ganglioside Sialidase is symptomatic and supportive. Prenatal diagnosis of the disorder is possible with transmission electron microscopy of cells acquired through amniocentesis. Genetic counseling is advised for families affected by this disorder. Therapies: Investigational Since prenatal diagnosis is now possible through amniocentesis, new treatments aimed at checking Ganglioside Sialidase Deficiency are now under investigation. One method involves replacing defective enzymes via enzyme replacement therapy and/or bone marrow transplants. Scientific study of gene replacement in animal models raises the hope that gene replacement therapy may someday be made available to people with genetic disorders such as Ganglioside Sialidase Deficiency. This disease entry is based upon medical information available through February 1990. 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 Ganglioside Sialidase Deficiency, please contact: National Organization for Rare Disorders (NORD) P.O. Box 8923 New Fairfield, CT 06812-1783 (203) 746-6518 Children's Association for Research on Mucolipidosis IV 6 Concord Drive Moncey, NY 10952 (914) 425-0639 National Digestive Diseases Information Clearinghouse Box NDDIC Bethesda, MD 20892 (301) 468-6344 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 MENDELIAN INHERITANCE IN MAN, 6th ed.: Victor A. McKusick; Johns Hopkins University Press, 1983. P. 836.