Important It is possible that the main title of the report Chromosome 18, Monosomy 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.
Short Arm 18 Deletion Syndrome
18p Deletion Syndrome
Monosomy 18p Syndrome
Chromosome 18, Monosomy 18p is a rare chromosomal disorder in which all or part of the short arm (p) of chromosome 18 is deleted (monosomic). The disorder is typically characterized by short stature, variable degrees of mental retardation, speech delays, malformations of the skull and facial (craniofacial) region, and/or additional physical abnormalities. Associated craniofacial defects may vary greatly in range and severity from case to case. However, such features commonly include an unusually small head (microcephaly); a broad, flat nose; a "carp-shaped" mouth; large, protruding ears; widely spaced eyes (ocular hypertelorism); and/or other abnormalities. Rarely (i.e., in about 10 percent of cases), Monosomy 18p may be associated with holoprosencephaly, a condition in which the forebrain (prosencephalon) fails to divide properly during embryonic development. Holoprosencephaly may result in varying degrees of mental retardation, other neurologic findings, and/or extremely variable midline facial defects, such as the presence of a single, central front tooth (maxillary incisor); closely spaced eyes (hypotelorism); an abnormal groove in the upper lip (cleft lip); incomplete closure of the roof of the mouth (cleft palate); and/or, in severe cases, absence of the nose and/or cyclopia. Cyclopia is characterized by fusion of the eye cavities (orbits) into a single cavity containing one eye.
In some individuals with Monosomy 18p, additional physical abnormalities may be present. Such findings commonly include a short, webbed neck; a broad chest with widely spaced nipples; relatively small hands and feet; and/or an unusually small penis (micropenis) and/or undescended testes (cryptorchidism) in affected males.
Monosomy 18p is usually caused by spontaneous (de novo) errors very early in the development of the embryo that appear to occur randomly for unknown reasons (sporadically).
Children's Craniofacial Association 13140 Coit Road Suite 517 Dallas, TX 75240 USA Tel: (214)570-9099 Fax: (214)570-8811 Tel: (800)535-3643 Email: contactCCA@ccakids.com Internet: http://www.ccakids.com
Support Organization for Trisomy 18, 13, and Related Disorders 2982 S. Union Street Rochester, NY 14624-1926 Fax: (585)594-1957 Tel: (800)716-7638 Email: firstname.lastname@example.org Internet: http://www.trisomy.org
March of Dimes Birth Defects Foundation 1275 Mamaroneck Avenue White Plains, NY 10605 Tel: (914)997-4488 Fax: (914)997-4763 Tel: (888)663-4637 Email: Askus@marchofdimes.com Internet: http://www.marchofdimes.com
The Arc 1825 K Street NW, Suite 1200 Washington, DC 20006 Tel: (202)534-3700 Fax: (202)534-3731 Tel: (800)433-5255 TDD: (817)277-0553 Email: email@example.com Internet: http://www.thearc.org
AmeriFace P.O. Box 751112 Limekiln, PA 19535 USA Tel: (702)769-9264 Fax: (702)341-5351 Tel: (888)486-1209 Email: firstname.lastname@example.org Internet: http://www.ameriface.org
Chromosome Disorder Outreach, Inc. P.O. Box 724 Boca Raton, FL 33429-0724 USA Tel: (561)395-4252 Fax: (561)395-4252 Email: email@example.com Internet: http://www.chromodisorder.org/CDO/
Chromosome 18 Registry & Research Society 7155 Oakridge Drive San Antonio, TX 78229 Tel: (210)657-4968 Fax: (210)657-4968 Email: firstname.lastname@example.org Internet: http://www.chromosome18.org
American Heart Association 7272 Greenville Avenue Dallas, TX 75231 Tel: (214)784-7212 Fax: (214)784-1307 Tel: (800)242-8721 Email: Review.email@example.com Internet: http://www.heart.org
UNIQUE - Rare Chromosome Disorder Support Group P.O. Box 2189 Caterham Surrey, CR3 5GN United Kingdom Tel: 4401883330766 Fax: 4401883330766 Email: firstname.lastname@example.org Internet: http://www.rarechromo.org
Craniofacial Foundation of America 975 East Third Street Chattanooga, TN 37403 Tel: (423)778-9176 Fax: (423)778-8172 Tel: (800)418-3223 Email: email@example.com Internet: http://www.craniofacialfoundation.org
Genetic and Rare Diseases (GARD) Information Center PO Box 8126 Gaithersburg, MD 20898-8126 Tel: (301)251-4925 Fax: (301)251-4911 Tel: (888)205-2311 TDD: (888)205-3223 Internet: http://rarediseases.info.nih.gov/GARD/
For a Complete Report
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Last Updated: 4/10/2009 Copyright 1989, 1990, 2001, 2003, 2009 National Organization for Rare Disorders, Inc.
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