CD-ROM Today (UK) (Spanish) 15/CDRT.iso/dp/0340/03402.txt

Text File | 1994-01-18 | 8.4 KB | 218 lines

$Unique_ID{BRK03402}
$Pretitle{}
$Title{18p-Syndrome}
$Subject{18p-Syndrome Short Arm 18 Deletion Syndrome Edwards Syndrome
(Trisomy-18) Trisomy E Trisomy 16-18 Down's Syndrome (Trisomy 21) Trisomy 14,
Partial Patau's Syndrome (Trisomy 13-15)}
$Volume{}
$Log{}

Copyright (C) 1989, 1990 National Organization for Rare Disorders, Inc.

639:
18p-Syndrome

** IMPORTANT **
It is possible that the main title of the article (18p-Syndrome) is not
the name you expected.  Please check the SYNONYM listing to find the
alternate names and disorder subdivisions covered by this article.

Synonyms

     Short Arm 18 Deletion Syndrome

Disorder Subdivisions:

     Edwards Syndrome (Trisomy-18)
     Trisomy E
     Trisomy 16-18

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

     Down's Syndrome (Trisomy 21)
     Trisomy 14, Partial
     Patau's Syndrome (Trisomy 13-15)

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.

18p-Syndrome (deletion of the short arm of the chromosome 18) is
characterized by unusual facial characteristics and mild to severe mental
retardation.  The patient often has an I.Q. averaging between 45 to 50.  In
some patients, however, there has been no mental deficiency at all.  Language
is often affected, and many people with 18p-Syndrome may not speak simple
sentences until seven to nine years of age.  Restlessness, emotional "ups and
downs", a fear of strangers, and lack of concentration are frequent
behavioral characteristics.

Symptoms

Symptoms of 18p-Syndrome may include a mild to moderate growth deficiency, a
tendency towards diminished muscle tension (hypotonia) and a smaller than
normal-sized brain (microencephaly) with mental retardation.

Drooping eyelids (ptosis), extra folds of skin on the inner corners of
the eyes (epicanthic folds), a low nasal bridge, and unusually widely spaced
eyes (hypertelorism) may also be present.  The patient may also have a
rounded face, small jaws (micrognathia), downturned corners of the mouth and
large protruding ears.

There may also be a high frequency of dental cavities (caries),
relatively small hands and feet, and depression of the breast bone.

Behavioral characteristics may include restlessness, emotional
instability, a fear of strangers and inability to concentrate.  Additionally,
speech is often affected and may be delayed for several years.

Disorder Subdivisions:

18q-Syndrome:
Patients with 18q-syndrome (long arm 18 deletion syndrome) are usually
retarded with I.Q.'s ranging from 40 to 85.  Growth deficiency, visual and
hearing problems may also occur.  Behavioral problems and inability to
appropriately relate to people and objects (autism) may also develop.
However, some patient's with 18q-deletion may have only very mild symptoms.
(For more information, choose "Autism" as your search term in the Rare
Disease Database.)

Trisomy 18, Edwards Syndrome, Trisomy E or 16-18:
Trisomy 18 is a genetic disorder which is apparent at birth.  Paternal
and maternal age are usually higher than average.  Babies may appear thin and
frail, have difficulty feeding and fail to thrive.  These children show
increased muscle tension (hypertonicity) with rigidity of the limbs, and
mental retardation.  (For more information on this disorder, choose "Trisomy
18" as your search term in the Rare Disease Database).

Causes

18p-Syndrome is characterized by deletion of the short arm (p) of the 18th
chromosome.  Chromosomes are located in the cell nucleus.  They are the
bearers of genes.  Normally human beings have 46 chromosomes.

Affected Population

In 18p-Syndrome there is a 60% predominance of affected females.  The average
parental ages of 31.3 years for the mothers, and 35.7 for the fathers may
indicate that parental age may be related to the occurrence of this disorder
in offspring.  Symptoms are apparent at birth.

Related Disorders

Symptoms of the following disorders can be similar to those of 18p-Syndrome.
Comparisons may be useful for a differential diagnosis:

Down's Syndrome (Trisomy 21) is the most common and readily identifiable
genetic condition associated with mental retardation.  It is caused by an
extra chromosome number 21.  This extra genetic material causes abnormal
development of body and brain.  Symptoms of Down's Syndrome include slanted
eyes with folds in the inner corners, white spots in the iris of the eye, a
transverse crease (Simian crease) on the palm of the hand, a flat nasal
bridge, short neck, unusually shaped ears, small head and mouth.  Mental
retardation and short stature are the other major characteristics of this
disorder.  (For more information on this disorder, choose "Down" as your
search term in the Rare Disease Database).

Partial Trisomy 14 causes motor, mental and growth retardation.  Seizures
or increased muscle tone, malformed ears and drooping eyelids may also occur.
Occasionally, heart and genital malformations may appear in children with
this birth defect.

Trisomy 13 Syndrome (Patau's Syndrome) is caused by an extra copy of
chromosome 13.  It occurs in approximately 1 in 5,000 live births and is
characterized by structurally unusual or irregular organs in the center of
the body (midline anomalies), defects of the brain, and cleft lip and/or
cleft palate.  (For more information on this disorder, choose "Trisomy 13" as
your search term in the Rare Disease Database).

Therapies:  Standard

Children with 18p-Syndrome may benefit from early intervention programs in
special education, physical therapy and language development.  Other
treatment is symptomatic and supportive.  Genetic counseling will be helpful
to the families affected by this syndrome.

Therapies:  Investigational

This disease entry is based upon medical information available through April
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 18p-Syndrome, please contact:

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

     The Chromosome 18 Registry and Research Society
     6302 Fox Head
     San Antonio, TX  78247
     [phone]

     Chromosome Deletion Outreach
     P.O. Box 164
     Holtsville, NY  11742
     [phone]

     S.O.F.T. and Other Related Disorders (Support Organization for Trisomy)
     9349 S. 12th St.
     Schoolcraft, MI  49087

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

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

For genetic information contact and genetic counseling information:

     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

MENDELIAN INHERITANCE IN MAN, 7th ed.:  Victor A. McKusick; Johns Hopkins
University Press, 1986.  Pp. 492.

INTERNAL MEDICINE, 2nd Ed.:  Jay H. Stein, ed.-in-chief; Little, Brown
and Co., 1987.  Pp. 753-774.

SMITH'S RECOGNIZABLE PATTERNS OF HUMAN MALFORMATION, 4th Ed : Kenneth
Jones, M.D.; Saunders, 1988.  Pp. 312, 313-314.

DUPLICATION 18p- WITH MILD INFLUENCE ON THE PHENOTYPE.  B. Johansson et
al; Am. J. Med. Genet April 29, 1988 issue (4)).  Pp. 871-4.

MULTIPLE CONGENITAL ANOMALIES/MENTAL RETARDATION (MCA/MR) SYNDROME DUE TO
PARTIAL 1q DUPLICATION AND POSSIBLE 18p DELETION:  A STUDY OF FOUR
INDIVIDUALS IN TWO FAMILIES.  R.M. Liberfarb et al; Am. J. Med. Genet (Issue
4(1), 1979.  Pp. 27-37.

THE 18p-SYNDROME (AUTHOR'S TRANSLATION).  F. Aksu; Monatsschr Kinderheilkd
(Issue September 125(9), 1977).  Pp. 845-7.