Chromosome 18, Monosomy 18p

National Organization for Rare Disorders, Inc.

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.

Synonyms

  • Short Arm 18 Deletion Syndrome
  • 18p Deletion Syndrome
  • 18p- Syndrome
  • Del(18p) Syndrome
  • Monosomy 18p Syndrome

Disorder Subdivisions

  • None

General Discussion

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).
.

Resources

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 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)997-4488
Fax: (914)997-4763
Tel: (888)663-4637
Email: Askus@marchofdimes.com
Internet: http://www.marchofdimes.com

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: (702)769-9264
Fax: (702)341-5351
Tel: (888)486-1209
Email: info@ameriface.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: info@chromodisorder.org
Internet: http://www.chromodisorder.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

American Heart Association
7272 Greenville Avenue
Dallas, TX 75231-4596
Tel: (214)373-6300
Fax: (214)373-0268
Tel: (800)242-8721
Email: Review.personal.info@heart.org
Internet: http://www.americanheart.org

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)778-9176
Fax: (423)778-8172
Tel: (800)418-3223
Email: terry.smyth@erlanger.org
Internet: http://www.craniofacialfoundation.org/www

Independent Holoprosencephaly Support Site
Web Site on the Internet
Email: hpe@att.net
Internet: http://hpe.home.att.net

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
Email: ordr@od.nih.gov
Internet: http://rarediseases.info.nih.gov/Default.aspx

For a Complete Report

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

related physicians

related services

Bon Secours International| Sisters of Bon Secours USA| Bon Secours Health System

This information does not replace the advice of a doctor. Healthwise disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. Privacy Policy. How this information was developed to help you make better health decisions.