Chromosome 18q- Syndrome

National Organization for Rare Disorders, Inc.

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It is possible that the main title of the report Chromosome 18q- Syndrome 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.


  • 18q Deletion Syndrome
  • 18q- Syndrome
  • Chromosome 18 Long Arm Deletion Syndrome
  • Chromosome 18, Monosomy 18Q
  • Del(18q) Syndrome
  • Monosomy 18q Syndrome

Disorder Subdivisions

  • None

General Discussion

Chromosome 18q- syndrome (also known as Chromosome 18, Monosomy 18q) is a rare chromosomal disorder in which there is deletion of part of the long arm (q) of chromosome 18. Associated symptoms and findings may vary greatly in range and severity from case to case. However, characteristic features include short stature; mental retardation; poor muscle tone (hypotonia); malformations of the hands and feet; and abnormalities of the skull and facial (craniofacial) region, such as a small head (microcephaly), a "carp-shaped" mouth, deeply set eyes, prominent ears, and/or unusually flat, underdeveloped midfacial regions (midfacial hypoplasia). Some affected individuals may also have visual abnormalities, hearing impairment, genital malformations, structural heart defects, and/or other physical abnormalities. Chromosome 18q- syndrome usually appears to result from spontaneous (de novo) errors very early during embryonic development that occur for unknown reasons (sporadically).

Supporting Organizations

Alexander Graham Bell Association for the Deaf and Hard of Hearing

3417 Volta Place NW
Washington, DC 20007-2778
United States
Tel: (202)337-5220
Fax: (202)337-8314
Tel: (866)337-5220


PO Box 751112
Las Vegas, NV 89136
Tel: (702)769-9264
Fax: (702)341-5351
Tel: (888)486-1209

American Heart Association

7272 Greenville Avenue
Dallas, TX 75231
Tel: (214)784-7212
Fax: (214)784-1307
Tel: (800)242-8721

Children's Craniofacial Association

13140 Coit Road
Suite 517
Dallas, TX 75240
Tel: (214)570-9099
Fax: (214)570-8811
Tel: (800)535-3643

Chromosome 18 Registry & Research Society

7155 Oakridge Drive
San Antonio, TX 78229
Tel: (210)657-4968
Fax: (210)657-4968

Chromosome Disorder Outreach, Inc.

P.O. Box 724
Boca Raton, FL 33429-0724
Tel: (561)395-4252
Fax: (561)395-4252

Craniofacial Foundation of America

975 East Third Street
Chattanooga, TN 37403
Tel: (423)778-9176
Fax: (423)778-8172
Tel: (800)418-3223

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

March of Dimes Birth Defects Foundation

1275 Mamaroneck Avenue
White Plains, NY 10605
Tel: (914)997-4488
Fax: (914)997-4763

NIH/National Eye Institute

31 Center Dr
MSC 2510
Bethesda, MD 20892-2510
United States
Tel: (301)496-5248
Fax: (301)402-1065

NIH/National Institute on Deafness and Other Communication Disorders

31 Center Drive, MSC 2320
Communication Avenue
Bethesda, MD 20892-3456
Tel: (301)402-0900
Fax: (301)907-8830
Tel: (800)241-1044

National Association for Parents of Children with Visual Impairments (NAPVI)

P.O. Box 317
Watertown, MA 02272-0317
Tel: (617)972-7441
Fax: (617)972-7444
Tel: (800)562-6265

The Arc

1825 K Street NW, Suite 1200
Washington, DC 20006
Tel: (202)534-3700
Fax: (202)534-3731
Tel: (800)433-5255

UNIQUE - Rare Chromosome Disorder Support Group

The Rare Chromosome Disorder Support Group
Surrey, RH8 9EE
United Kingdom
Tel: 441883723356
Email: or

For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders (NORD). A copy of the complete report can be downloaded free from the NORD website for registered users. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational therapies (if available), and references from medical literature. For a full-text version of this topic, go to and click on Rare Disease Database under "Rare Disease Information".

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 or email

Last Updated:  1/11/1970
Copyright  2009 National Organization for Rare Disorders, Inc.