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1994-01-17
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$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.