Chromosome 9, Trisomy 9p (Multiple Variants)
National Organization for Rare Disorders, Inc.
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General Discussion
Chromosome 9, trisomy 9p is a rare chromosomal syndrome in which a portion of the 9th chromosome appears three times (trisomy) rather than twice in cells of the body. Chromosomes are found in the nucleus of all body cells. They carry the genetic characteristics of each individual. Pairs of human chromosomes are numbered from 1 through 22, with an unequal 23rd pair of X and Y chromosomes for males and two X chromosomes for females. Each chromosome has a short arm designated as "p," a long arm identified by the letter "q," and a narrowed region at which the two arms are joined (centromere). Chromosomes are further subdivided into bands that are numbered outward from the centromere. For example, the short arm of chromosome 9 includes bands 9p11 to 9p24, and the long arm includes bands 9q11 to 9q34.
In trisomy 9p, the trisomy (or duplicated material) may involve a portion of the short arm (9p), the entire short arm, or the short arm and a portion of the long arm (9q) of chromosome 9. Evidence suggests that, in many cases, associated symptoms and findings may be relatively similar among affected infants despite differing lengths of the trisomic (duplicated) segment of 9p. However, in those with larger trisomies (e.g., extending to middle or end [distal] regions of 9q), additional features may also be present that appear to correlate with the extent of the duplication. Additionally, certain individuals with duplications of specific areas of chromosome 9p have developed any symptoms or only very mild or subtle symptoms.
Children with Trisomy 9p are affected by delays in reaching developmental milestones like crawling or walking (developmental delays), growth deficiency, and distinctive malformations of the skull and facial (craniofacial) region. As children grow older, intellectual disability may become apparent.
In some instances, additional physical abnormalities may also be present, such as other skeletal defects and/or structural malformations of the heart that are present at birth (congenital heart defects). In some cases, the trisomy appears to result from a balanced chromosomal rearrangement in one of the parents; in others, it is thought to arise from spontaneous (de novo) errors very early in embryonic development that occur for unknown reasons (sporadically).
The chromosomal abnormality was originally reported in the medical literature in1970. Trisomy 9p was first proposed as a distinct syndrome with characteristic symptoms and findings in 1975.
Supporting Organizations
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
- Website: http://www.ameriface.org
American Heart Association
- 7272 Greenville Avenue
- Dallas, TX 75231
- Tel: (214)784-7212
- Fax: (214)784-1307
- Tel: (800)242-8721
- Email: Review.personal.info@heart.org
- Website: http://www.heart.org
Birth Defect Research for Children, Inc.
- 976 Lake Baldwin Lane
- Orlando, FL 32814
- USA
- Tel: (407)895-0802
- Email: staff@birthdefects.org
- Website: http://www.birthdefects.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
- Website: http://www.craniofacialfoundation.org/www
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
- Website: http://rarediseases.info.nih.gov/GARD/
March of Dimes
- 1275 Mamaroneck Avenue
- White Plains, NY 10605
- Tel: (914)997-4488
- Fax: (914)997-4763
- Email: AskUs@marchofdimes.org or preguntas@nacersano.org
- Website: http://www.marchofdimes.org and nacersano.org
Support Organisation for Trisomy and Related Disorders
- Email: mandyjc@amnet.net.au
- Website: http://www.trisomy9.org
Support Organization for Trisomy 13/18 and Related Disorders, UK
- c/o Christine Rose
- 48 Froggatts Ride
- West Midlands, B76 2TQ SOFT
- United Kingdom
- Tel: 1213513122
- Email: enquiries@soft.org.uk
- Website: http://www.soft.org.uk
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: barbv@trisomy.org
- Website: http://www.trisomy.org
The Arc
- 1825 K Street NW, Suite 1200
- Washington, DC 20006
- Tel: (202)534-3700
- Fax: (202)534-3731
- Tel: (800)433-5255
- Email: info@thearc.org
- Website: http://www.thearc.org
Trisomy 9 International Parent Support (9TIPS)
- 4027 E. Piedmont Drive
- Highland, CA 92346
- USA
- Tel: (909)862-4470
- Email: atoddna@sprynet.com
- Website: http://www.trisomy9.org/9tips.htm
UNIQUE - Rare Chromosome Disorder Support Group
- G1 The Stables
- Station Road West
- Oxted, RH8 9EE
- United Kingdom
- Tel: 0044 (0)1883 723356
- Email: info@rarechromo.org
- Website: http://www.rarechromo.org/html/home.asp
For a Complete Report
This is an abstract of a report from the National Organization for Rare Disorders (NORD). For a full-text version of this report, go to www.rarediseases.org and click on Rare Disease Database under "Rare Disease Information".
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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.
Last Updated: 5/1/2015
Copyright 2015 National Organization for Rare Disorders, Inc.
