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$Unique_ID{BRK03600}
$Pretitle{}
$Title{Chromosome 22 Ring}
$Subject{Chromosome 22 Ring Ring 22 Ring 22 Chromosome Chromosomal Disorders}
$Volume{}
$Log{}
Copyright (C) 1992 National Organization for Rare Disorders, Inc.
929:
Chromosome 22 Ring
** IMPORTANT **
It is possible that the main title of the article (Chromosome 22 Ring) is
not the name you expected. Please check the SYNONYMS listing to find the
alternate name and disorder subdivisions covered by this article.
Synonyms
Ring 22
Ring 22, Chromosome
Information on the following diseases can be found in the Related
Disorders section of this report:
Chromosomal Disorders
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.
Chromosome 22 Ring is a rare chromosomal disorder in which the patient
has a breakage of chromosome 22 at both ends, and the ends of the chromosome
join together to form a ring. The amount of genetic material lost at the two
ends of the chromosome can vary. As a result, a patient with very little
absent genetic material may have no apparent symptoms while a patient with a
significant part of the chromosomal ends missing may have many symptoms. The
most apparent features of this disorder are mental retardation,
incoordination of movement and muscle weakness.
Symptoms
Chromosome 22 Ring is a rare chromosomal disorder in which the symptoms
depend on the amount of genetic material lost on the small and long arms
(ends) of the twenty-second chromosome. As a result, patients symptoms can
vary greatly.
The features seen most often in Chromosome 22 Ring are mental
retardation, muscle weakness and incoordination of movement.
Other symptoms that have been found in some patients with Chromosome 22
Ring may be: a smaller than normal nose; a large rounded nose; large ears; a
high arched palate of the roof of the mouth; widely spaced eyes; a vertical
fold over the inner corner of the eye; and/or drooping eyelids.
Symptoms that have been found in a few patients with Chromosome 22 Ring
are: underdeveloped toenails; webbing of the fingers and toes (syndactyly);
small eyes; long eyelashes; and heart defects.
Causes
Chromosome 22 Ring is a rare chromosomal disorder caused by a deletion of
chromosome 22 at both ends and a joining of the ends to form a ring. The
genetic material lost from the ends can vary from a small amount with few
symptoms to a significant amount causing many symptoms. There is no apparent
reason why this occurs. Most chromosomal deletions occur "de novo" which
means that they occur very early in the development of the embryo. The
parents of the affected child typically have normal chromosomes and a very
low possibility of having another child with a chromosomal abnormality.
A very small number of cases of Chromosome 22 Ring have been reported as
occuring in more than one member of a family (familial).
Affected Population
Chromosome 22 Ring is a rare chromosomal disorder that affects males more
often than females. This disorder is usually detected at birth or during
prenatal testing. There have been more than 40 cases of this disorder
reported in the medical literature.
Related Disorders
Symptoms of the following disorders can be similar to those of Chromosome 22
Ring. Comparisons may be useful for a differential diagnosis:
Many chromosomal disorders involving mental retardation have some
features similar to Chromosome 22 Ring. The only way to determine which
chromosomal disorder a patient has is through genetic testing. (For more
information choose "mental retardation" as your search term in the Rare
Disease Database).
Therapies: Standard
Patients with Chromosome 22 Ring and poor muscle tone may benefit from
physical therapy. Special education and related services will be of benefit
to children with this disorder.
Genetic counseling may be of benefit for patients and their families.
Other treatment is symptomatic and supportive.
Therapies: Investigational
Research on birth defects and their causes is ongoing. The National
Institutes of Health (NIH) is sponsoring the Human Genome Project which is
aimed at mapping every gene in the human body and learning why they sometimes
malfunction. It is hoped that this new knowledge will lead to prevention and
treatment of genetic disorders in the future.
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 Chromosome 22 Ring, please contact:
National Organization for Rare Disorders (NORD)
P.O. Box 8923
New Fairfield, CT 06812-1783
(203) 746-6518
Chromosome Deletion Outreach
P.O. Box 164
Holtsville, NY 11742
(516) 736-6754
Association for Retarded Citizens of the U.S.
P.O. Box 6109
Arlington, TX 76005
(817) 640-0204
(800) 433-0525
NIH/National INstitute of Child Health and Human Development
9000 Rockville Pike
Bethesda, MD 20892
(301) 496-5133
For Genetic Information and Genetic Counseling Referrals:
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
BIRTH DEFECTS ENCYCLOPEDIA, Mary Louise Buyse, M.D., Editor-In-Chief;
Blackwell Scientific Publications, 1990. Pp. 394.
DELETED RING CHROMOSOME 22 IN A MENTALLY RETARDED BOY: K.H. Gustavson, et
al.; Clin Genet (April, 1986, issue 29(4)). Pp. 337-41.
RING CHROMOSOME 22: A CASE REPORT: C. Severien, et al.; Klin Padiatr
(Nov-Dec, 1991, issue 203(6)). Pp. 467-9.