CD-ROM Today 1996 January/CD-ROM Today 1996 January.iso/dp/0366/03669.txt

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$Unique_ID{BRK03669}
$Pretitle{}
$Title{Down's Syndrome}
$Subject{Down's Syndrome Mongolism Trisomy 21 Syndrome Chromosome 21, Mosiac
21 Syndrome Chromosome 21, Translocation 21 Syndrome Trisomy G Syndrome
Chromosome X, Poly X}
$Volume{}
$Log{}

Copyright (C) 1984, 1985, 1987, 1988, 1990, 1992 National Organization
for Rare Disorders, Inc.

34:
Down's Syndrome

** IMPORTANT **
It is possible that the main title of the article (Down's Syndrome) is
not the name you expected.  Please check the SYNONYMS listing to find the
alternate name and disorder subdivisions covered by this article.

Synonyms

     Mongolism
     Trisomy 21 Syndrome
     Chromosome 21, Mosiac 21 Syndrome
     Chromosome 21, Translocation 21 Syndrome
     Trisomy G Syndrome

Information on the following diseases can be found in the Related
Disorders section of this report:

     Chromosome X, Poly X

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.


Down's Syndrome is the most common and readily identifiable genetic
condition associated with mental retardation.  Facial, skeletal, and
frequently cardiac abnormalities are among the more the 50 features seen in
this syndrome.  It is rare to find all symptoms or even most of them in one
person with Down's Syndrome.

Symptoms

Some common characteristics of Down's Syndrome include an usually small head
(microencephaly); a small mouth; a flat nasal bridge; white (Brushfield)
spots in the iris of the eyes; a downward slant to the eyes with a fold of
skin on the inner corners (epicanthal folds); small ears that may be folded
over at the top; a short neck; a transverse (Simian) crease on the palm of
the hands; and poor muscle tone (hypotonia).

All children with Down's Syndrome have some degree of mental retardation.
Generally this retardation is in the mild to moderate range, but sometimes it
can be profound.

Approximately 50 percent of children with Down's Syndrome have some form
of congenital heart disease.  They are prone to respiratory, eye, and ear
problems.  These children are 20 times more likely to develop leukemia than
the general population.  It is believed that leukemia itself is not inherited
but results from an increased genetic susceptibility to environmental factors
that may cause leukemia.  The life expectancy of people with Down's Syndrome
is close to normal.

Causes

In Down's Syndrome, the mental and physical abnormalities develop due to the
presence of an extra chromosome contributed by either the egg or the sperm
cell.  There are a total of 47 chromosomes instead of the normal 46.  Trisomy
21, with three copies of chromosome 21, is the most common form of Down's
Syndrome.

Affected Population

Down's Syndrome occurs in approximately 1 in 800 live births.  It is
estimated that 7,000 children are born with Down's Syndrome in the United
States each year.  The incidence is higher for children born to women and men
over the age of 35.  The most common forms of the syndrome do not usually
occur more than once in a family.  All races and economic levels are affected
equally.

Related Disorders

Symptoms of the following disorders can be similar to those of Down's
Syndrome.  Comparisons may be useful for a differential diagnosis:

Chromosome X, Poly X Syndrome is a rare chromosomal abnormality that is
the result of the presence of extra X chromosome (at least three or four
extras).  This disorder occurs in females only and the facial features
sometimes resemble those of Down's Syndrome.  The major features of this
condition may include short stature, delayed growth, a short neck, small head
(microencephaly), flat nasal bridge, low-set ears and mild to moderate mental
retardation.  Other features may include eye and ear defects, joint defects
and dental abnormalities.  (For more information about other disorders
characterized by mental retardation, choose "Mental Retardation" as your
search term on the Rare Disease Database).

Therapies:  Standard

Down's Syndrome and its basic features cannot be altered.  However, children
with Down's Syndrome can benefit from early intervention programs such as
those recommended by the Association for Retarded Citizens (ARC) and the
Association for Children with Down's Syndrome, and other agencies listed in
the "Resources" section of this report.

Parent and infant education can begin immediately after birth.  The
individual child receives direct service programming to develop learning,
language, mobility, self care and socialization skills.  Toddler and
preschool programs further enhance the acquisition of skills to enable people
with Down's Syndrome to reach their maximum potential.

Heart defects may require surgery during infancy or childhood.  Prenatal
tests are available to determine whether a fetus has Down's Syndrome before
birth.

Therapies:  Investigational

Down's Syndrome, as well as other similar disorders, are the focus of ongoing
scientific investigations.  Studies are underway to determine the complex
structure of chromosomes and the genes that are contained in all chromosomes,
including chromosome 21.

This disease entry is based upon medical information available through
October 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 Down's syndrome, please contact:

     National Organization for Rare Disorders (NORD)
     P.O. Box 8923
     New Fairfield, CT  06812-1783
     [phone]

     Association for Children with Down's Syndrome
     2616 Martin Avenue
     Bellmore, NY  11710
     [phone]

     National Down's Syndrome Congress
     1640 West Roosevelt Road
     Chicago, IL  60608
     [phone]
     [phone]

     National Association for Down's Syndrome
     P.O. Box 63
     Oak Park, IL  60303
     [phone]

     National Down's Syndrome Society
     70 West 40th Street
     New York, NY  10018
     [phone]
     [phone]

     National Center for Down's Syndrome
     9 Westbourne Road
     EDG Baston
     Birmingham, B-15, England
     [phone]

     NIH/National Institute of Child Health and Human Development (NICHD)
     9000 Rockville Pike
     Bethesda, MD  20892
     [phone]

     National Association for Retarded Citizens of the U.S. (ARC)
     P.O. Box 6109
     Arlington, TX  76005
     [phone]
     [phone]

     National Institute of Mental Retardation
     (Canadian Association for the Mentally Retarded)
     York University
     Kinsmen NIMR Building
     4700 Keele Street
     Downsview, Ontario M3J 1P3
     Canada
     [phone]

For Genetic Information and Genetic Counseling Referrals:

     March of Dimes Birth Defects Foundation
     1275 Mamaroneck Avenue
     White Plains, NY 10605
     [phone]

     Alliance of Genetic Support Groups
     35 Wisconsin Circle, Suite 440
     Chevy Chase, MD  20815
     (800) 336-GENE
     [phone]

References

SMITH'S RECOGNIZABLE PATTERNS OF HUMAN MALFORMATION, 4th ed., Kenneth L.
Jones, M.D., W.B. Saunders, Co. 1988.  Pp. 10-12, 13-15.

THE MERCK MANUAL 15th ed:  R. Berkow, et al:  eds; Merck, Sharp & Dohme
Research Laboratories, 1987.  Pp. 167-70.

BIRTH DEFECTS ENCYCLOPEDIA, Mary Louise Buyse, M.D., Editor-In-Chief;
Blackwell Scientific Publications, 1990.  Pp. 391-392.

NELSON TEXTBOOK OF PEDIATRICS, 14TH Ed.; Richard E. Behrman, Editors;
W.B. Saunders Company, 1991.  Pp. 282-284.

CLINICAL ASPECTS OF DOWN SYNDROME FROM INFANCY TO ADULTHOOD, S.M.
Pueschel; Am J Med Genet Suppl (1990; 7): Pp. 52-56.