Synonyms

• Tetrasomy, Short Arm of Chromosome 18

Disorder Subdivisions

• None

General Discussion

Chromosome 18, Tetrasomy 18p is a very rare chromosomal disorder in which the short arm of the 18th chromosome (18p) appears four times (tetrasomy) rather than twice in cells of the body. Individuals with a normal chromosomal make-up (karyotype) have two 18th chromosomes, both of which have a short arm ("18p") and a long arm ("18q"). However, in individuals with Chromosome 18, Tetrasomy 18p, four short arms (18ps) are present in cells of the body rather than the normal two.

The symptoms of Chromosome 18, Tetrasomy 18p may vary from case to case. Many affected individuals may have abnormalities of the head and facial (craniofacial) area; malformations of the spine, hands, and/or feet; neuromuscular abnormalities, such as increased muscle tone (hypertonia), increased reflex reactions (hyperreflexia), and difficulty coordinating movement; kidney (renal) malformations; and/or additional physical abnormalities. In addition, children and adults with Chromosome 18, Tetrasomy 18p often exhibit moderate to severe mental retardation, limitations in speech, and/or behavioral abnormalities. In most cases, Chromosome 18, Tetrasomy 18p is the result of a spontaneous (de novo) genetic change (mutation) early in embryonic development that occurs for unknown reasons (sporadic).

Resources

Children's Craniofacial Association
13140 Coit Road
Suite 517
Dallas, TX 75240
USA
Tel: 2145709099
Fax: 2145708811
Tel: 8005353643
Email: csmith@ccakids.com
Internet: http://www.ccakids.com

Support Organization for Trisomy 18, 13, and Related Disorders
2982 South Union Street
Rochester, NY 14624-1926
Fax: (585)594-1957
Tel: (800)716-7638
Email: barbv@trisomy.org
Internet: http://www.trisomy.org

March of Dimes Birth Defects Foundation
1275 Mamaroneck Avenue
White Plains, NY 10605
Tel: (914)428-7100
Fax: (914)997-4763
Tel: (888)663-4637
Email: Askus@marchofdimes.com
Internet: http://www.marchofdimes.com

The Arc (a national organization on mental retardation)
1010 Wayne Ave
Suite 650
Silver Spring, MD 20910
Tel: (301)565-3842
Fax: (301)565-3843
Tel: (800)433-5255
TDD: (817)277-0553
Email: info@thearc.org
Internet: http://www.thearc.org/

AmeriFace
PO Box 751112
Las Vegas, NV 89136
USA
Tel: 7027699264
Fax: 7023415351
Tel: 8884861209
Email: info@ameriface.org
Internet: http://www.ameriface.org

Chromosome Disorder Outreach, Inc.
P.O. Box 724
Boca Raton, FL 33429-0724
USA
Tel: 5613954252
Fax: 5613954252
Email: info@chromodisorder.org
Internet: http://www.chromodisorder.org

National Kidney Foundation
30 East 33rd Street
New York, NY 10016
Tel: (212)889-2210
Fax: (212)689-9261
Tel: (800)622-9010
Email: info@kidney.org
Internet: http://www.kidney.org

Chromosome 18 Registry & Research Society
7155 Oakridge Drive
San Antonio, TX 78229
Tel: (210)657-4968
Fax: (210)657-4968
Email: office@chromosome18.org
Internet: http://www.chromosome18.org

NIH/National Kidney and Urologic Diseases Information Clearinghouse
3 Information Way
Bethesda, MD 20892-3580
Tel: (800)891-5390
Email: nkudic@info.niddk.nih.gov
Internet: http://kidney.niddk.nih.gov/

UNIQUE - Rare Chromosome Disorder Support Group
P.O. Box 2189
Caterham
Surrey, Intl CR3 5GN
United Kingdom
Tel: 44 0 1883 330766
Fax: 44 0 1883 330766
Email: info@rarechromo.org
Internet: http://www.rarechromo.org

Craniofacial Foundation of America
975 East Third Street
Chattanooga, TN 37403
Tel: (423)778-9192
Fax: (423)778-8172
Tel: (800)418-3223
Email: farmertm@erlanger.org
Internet: http://www.craniofacialcenter.com

MUMS (Mothers United for Moral Support, Inc) National Parent-to-Parent Network
150 Custer Court
Green Bay, WI 54301-1243
USA
Tel: 9203365333
Fax: 9203390995
Tel: 8773365333
Email: mums@netnet.net
Internet: http://www.netnet.net/mums/

Tetrasomy 18p Canada
Toronto , ON Canada

Tel: (416)-76-8-7311
Email: Lorrine@teksavvy.com
Internet: http://www.tetrasomy18p.ca

For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders, Inc. ® (NORD). A copy of the complete report can be obtained for a small fee by visiting the NORD website. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational treatments (if available), and references from medical literature. For a full-text version of this topic, see http://www.rarediseases.org/search/rdblist.html

The information provided in this report is not intended for diagnostic purposes. It is provided for informational purposes only. NORD recommends that affected individuals seek the advice or counsel of their own personal physicians.

It is possible that the title of this topic is not the name you selected. Please check the Synonyms listing to find the alternate name(s) and Disorder Subdivision(s) covered by this report.

This disease entry is based upon medical information available through the date at the end of the topic. 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.

For additional information and assistance about rare disorders, please contact the National Organization for Rare Disorders at P.O. Box 1968, Danbury, CT 06813-1968; phone (203) 744-0100; web site www.rarediseases.org or email orphan@rarediseases.org

Last Updated:  5/21/2008
Copyright  1996, 2001National Organization for Rare Disorders, Inc.