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$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.