$Unique_ID{BRK03602} $Pretitle{} $Title{Chromosome 9 Ring} $Subject{Chromosome 9 Ring Ring 9 Ring 9 Chromosome Chromosomal Disorders} $Volume{} $Log{} Copyright (C) 1993 National Organization for Rare Disorders, Inc. 952: Chromosome 9 Ring ** IMPORTANT ** It is possible that the main title of the article (Chromosome 9 Ring) is not the name you expected. Please check the SYNONYMS listing to find the alternate name and disorder subdivisions covered by this article. Synonyms Ring 9 Ring 9, Chromosome Information on the following diseases can be found in the Related Disorders section of this report: Chromosomal Disorders General Discussion ** REMINDER ** The Information contained in the Rare Disease Database is provided for educational purposes only. It should not be used for diagnostic or treatment purposes. If you wish to obtain more information about this disorder, please contact your personal physician and/or the agencies listed in the "Resources" section of this report. Chromosome 9 Ring is a rare chromosomal disorder in which the patient has a breakage of chromosome 9 at both ends, and the ends of the chromosome join together to form a ring. The amount of genetic material lost at the two ends of the chromosome can vary. As a result, an affected individual with very little absent genetic material may have no apparent symptoms, while a patient with a significant part of the chromosomal ends missing may have more severe symptoms. Symptoms of this disorder may include unusual facial features, heart defects, moderate to severe mental retardation, and skeletal abnormalities. Symptoms Chromosome 9 Ring is a rare chromosomal disorder in which the symptoms depend on the amount of genetic material lost on the small and long arms (ends) of the 9th chromosome. As a result, patients symptoms can very greatly. Some patients with Chromosome 9 Ring have very mild symptoms while others may be more severely affected. The symptoms of this chromosomal abnormality are often very mild. Facial abnormalities may include a small head (microcephaly), a triangular shaped forehead (trigonocephaly), eyes that are downslanting and protrude outward, an exaggerated arch to the eyebrows, a small chin and/or a short neck. Heart defects, as well as skeletal abnormalities including cleft palate, have been seen in some affected individuals. (For more information choose "Cleft Palate" as your search term in the Rare Disease Database). A few affected males may have abnormal external genitalia and/or an abnormal urinary opening located on the underside of the penis (hypospadias). Mental retardation can vary from very mild to severe. Some affected individuals may become agitated easily or they may be very shy and withdrawn. Causes Chromosome 9 Ring is a chromosomal disorder caused by a deletion of Chromosome 9 at both ends and the joining of the ends to form a ring. The amount of genetic material lost from the ends can vary from a small amount causing few symptoms to a significant amount causing many symptoms. There is no apparent reason why this occurs. Most chromosomal deletions occur "de novo" which means that they occur very early in the development of the embryo. The parents of the affected child typically have normal chromosomes and a very low possibility of having another child with a chromosomal abnormality. A parent may have Chromosome 9 Ring with few apparent symptoms. When this is the case, the parent may transmit the chromosomal abnormality to the child. In these cases the affected parent has a fifty percent chance of having another child with Chromosome 9 Ring. Affected Population Chromosome 9 Ring is a very rare chromosomal abnormality that affects males and females equally. There have been approximately twelve cases of this disorder reported in the medical literature, although there may be several hundred unreported cases. Related Disorders Symptoms of the following disorders can be similar to those of Chromosome 9 Ring. Comparisons may be useful for a differential diagnosis: Many chromosomal disorders involving mental retardation have some features similar to Chromosome 9 Ring. The only way to determine which chromosomal abnormality an affected person has is through genetic testing. (For more information choose "Mental Retardation and "chromosomal disorder" as your search term in the Rare Disease Database.) Therapies: Standard Special education and related services will be beneficial to children with Chromosome 9 Ring. In cases where cleft palate occurs, surgical treatment and speech therapy may be warranted. (For more information on the treatment of cleft palate, choose "Cleft Palate" as your search term in the Rare Disease Database). Genetic counseling may be of benefit for patients and their families. Other treatment is symptomatic and supportive. Therapies: Investigational Research on birth defects and their causes is ongoing. The National Institutes of Health (NIH) is sponsoring the Human Genome Project which is aimed at mapping every gene in the human body and learning why they sometimes malfunction. It is hoped that this new knowledge will lead to prevention and treatment of birth defects in the future. This disease entry is based upon medical information available through June 1993. 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. Resources For more information on Chromosome 9 Ring, please contact: National Organization for Rare Disorders (NORD) P.O. Box 8923 New Fairfield, CT 06812-1783 (203) 746-6518 Chromosome Deletion Outreach P.O. Box 164 Holtsville, NY 11742 (516) 736-6754 Association for Retarded Citizens of the U.S. P.O. Box 6109 Arlington, TX 76005 (817) 640-0204 (800) 433-0525 American Cleft Palate Cranial Facial Association 1218 Granview Ave. Pittsburgh, PA 15211 (412) 681-1376 (800) 24CLEFT For Genetic Information and Genetic Counseling Referrals: March of Dimes Birth Defects Foundation 1275 Mamaroneck Avenue White Plains, NY 10605 (914) 428-7100 Alliance of Genetic Support Groups 35 Wisconsin Circle, Suite 440 Chevy Chase, MD 20815 (800) 336-GENE (301) 652-5553 References BIRTH DEFECTS ENCYCLOPEDIA, Mary Louise Buyse, M.D., Editor-In-Chief; Blackwell Scientific Publications, 1990. P. 354. APPARENT PRADER-WILLI PHENOTYPE IN A WOMAN WITH RING CHROMOSOME 9: R.O. Hess, et al., Am J Med Genet Suppl (1987, issue 3). Pp. 133-8. RING CHROMOSOME 9. CASE REPORT AND REVIEW OF THE LITERATURE: S. Manouvrier-Hanu et al.; Ann Genet (1988, issue 31(4)). Pp. 250-3.