Important It is possible that the main title of the report Chromosome 15 Ringis not the name you expected.
Synonyms
Ring 15
Ring 15, Chromosome
r15
Ring 15, Chromosome (mosaic pattern)
Disorder Subdivisions
None
General Discussion
Chromosome 15 Ring results from loss (deletion) of genetic material from both ends of the 15th chromosome and a joining of the ends to form a ring. 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" and a long arm identified by the letter "q." Chromosomes are further subdivided into bands that are numbered.
In individuals with Chromosome 15 Ring, the variability of associated symptoms and findings may depend upon the amount and location of genetic material lost from the 15th chromosome, the stability of the ring chromosome during subsequent cellular divisions, or other factors. Evidence suggests that the clinical features seen in Chromosome 15 Ring appear to result from deletions of genetic material from the long arm (q) of chromosome 15 (known as "monosomy 15q"), with the ring chromosome typically replacing a normal 15th chromosome. In addition, in some cases, only a certain percentage of an individual's cells may contain Chromosome 15 Ring, while other cells may have a normal chromosomal makeup (a finding known as "chromosomal mosaicism"), potentially affecting the variability of associated symptoms and findings.
In most cases, Chromosome 15 Ring appears to be caused by spontaneous (de novo) errors very early in embryonic development. In such cases, the parents of the affected child usually have normal chromosomes and a relatively low risk of having another child with the chromosomal abnormality. However, there have been rare cases in which a parent of an affected individual also has Chromosome 15 Ring. In such instances, the chances are greater of having another child with the chromosomal abnormality. In addition, a few cases have been reported in which Chromosome 15 Ring has been the result of a "balanced translocation" in one of the parents. Translocations occur when regions of certain chromosomes break off and are rearranged, resulting in shifting of genetic material and an altered set of chromosomes. If a chromosomal rearrangement is balanced, meaning that it consists of an altered but balanced set of chromosomes, it is usually harmless to the carrier. However, such a chromosomal rearrangement may be associated with an increased risk of abnormal chromosomal development in the carrier's offspring.
Chromosomal analysis and genetic counseling are typically recommended for parents of an affected child to help confirm or exclude the presence of Chromosome 15 Ring, potential mosaicism, or a balanced translocation in one of the parents.
Many individuals with Chromosome 15 Ring have some features similar to those associated with Russell-Silver syndrome (RSS), which is a genetic disorder characterized by growth deficiency and short stature, distinctive facial abnormalities, and other features. (For further information, please see the "Related Disorders" section below.) In some of these cases, genetic analysis has indicated that the prenatal and postnatal growth retardation associated with Chromosome 15 Ring (and potentially suggestive of RSS) may result from deletion of a gene known as the insulin-like growth factor I receptor (IGF1R) gene, which has been mapped to the long arm of chromosome 15 (15q25-q26). .
Resources
Human Growth Foundation 997 Glen Cove Avenue Glen Head, NY 11545 Tel: (516)671-4041 Fax: (516)671-4055 Tel: (800)451-6434 Email: hgf1@hgfound.org Internet: http://www.hgfound.org/
Children's Craniofacial Association 13140 Coit Road Suite 517 Dallas, TX 75240 USA Tel: 2145709099 Fax: 2145708811 Tel: 8005353643 Email: csmith@ccakids.com Internet: http://www.ccakids.com
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/
AmeriFace PO Box 751112 Las Vegas, NV 89136 USA Tel: 7027699264 Fax: 7023415351 Tel: 8884861209 Email: info@ameriface.org Internet: http://www.ameriface.org
Chromosome Disorder Outreach, Inc. P.O. Box 724 Boca Raton, FL 33429-0724 USA Tel: 5613954252 Fax: 5613954252 Email: info@chromodisorder.org Internet: http://www.chromodisorder.org
Little People of America, Inc. 250 El Camino Real Suite 201 Tustin, CA 92780 Tel: (714)368-3689 Tel: (888)572-2001 Email: info@lpaonline.org Internet: http://www.lpaonline.org
American Heart Association National Center 7272 Greenville Avenue Dallas, TX 75231-4596 Tel: (214)373-6300 Fax: (214)373-0268 Tel: (800)242-8721 Email: inquire@heart.org Internet: http://www.americanheart.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
MUMS (Mothers United for Moral Support, Inc) National Parent-to-Parent Network 150 Custer Court Green Bay, WI 54301-1243 USA Tel: 9203365333 Fax: 9203390995 Tel: 8773365333 Email: mums@netnet.net Internet: http://www.netnet.net/mums/
For a Complete Report
This is an abstract of a report from the National Organization for Rare Disorders, Inc. (r) (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
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 www.rarediseases.org or email orphan@rarediseases.org
Last Updated: 5/27/2008 Copyright 1993, 1997, 2001, 2003National Organization for Rare Disorders, Inc.
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