Important
Important
It is possible that the main title of the report Chromosome 18, Tetrasomy 18p is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.
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 307
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/
AboutFace USA
PO Box 158
South Beloit, IL 61080
USA
Tel: 8884861209
Email: info@AboutFaceUSA.org
Internet: http://www.aboutfaceusa.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
