$Unique_ID{BRK03600} $Pretitle{} $Title{Chromosome 22 Ring} $Subject{Chromosome 22 Ring Ring 22 Ring 22 Chromosome Chromosomal Disorders} $Volume{} $Log{} Copyright (C) 1992 National Organization for Rare Disorders, Inc. 929: Chromosome 22 Ring ** IMPORTANT ** It is possible that the main title of the article (Chromosome 22 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 22 Ring 22, 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 22 Ring is a rare chromosomal disorder in which the patient has a breakage of chromosome 22 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, a patient 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 many symptoms. The most apparent features of this disorder are mental retardation, incoordination of movement and muscle weakness. Symptoms Chromosome 22 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 twenty-second chromosome. As a result, patients symptoms can vary greatly. The features seen most often in Chromosome 22 Ring are mental retardation, muscle weakness and incoordination of movement. Other symptoms that have been found in some patients with Chromosome 22 Ring may be: a smaller than normal nose; a large rounded nose; large ears; a high arched palate of the roof of the mouth; widely spaced eyes; a vertical fold over the inner corner of the eye; and/or drooping eyelids. Symptoms that have been found in a few patients with Chromosome 22 Ring are: underdeveloped toenails; webbing of the fingers and toes (syndactyly); small eyes; long eyelashes; and heart defects. Causes Chromosome 22 Ring is a rare chromosomal disorder caused by a deletion of chromosome 22 at both ends and a joining of the ends to form a ring. The genetic material lost from the ends can vary from a small amount with 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 very small number of cases of Chromosome 22 Ring have been reported as occuring in more than one member of a family (familial). Affected Population Chromosome 22 Ring is a rare chromosomal disorder that affects males more often than females. This disorder is usually detected at birth or during prenatal testing. There have been more than 40 cases of this disorder reported in the medical literature. Related Disorders Symptoms of the following disorders can be similar to those of Chromosome 22 Ring. Comparisons may be useful for a differential diagnosis: Many chromosomal disorders involving mental retardation have some features similar to Chromosome 22 Ring. The only way to determine which chromosomal disorder a patient has is through genetic testing. (For more information choose "mental retardation" as your search term in the Rare Disease Database). Therapies: Standard Patients with Chromosome 22 Ring and poor muscle tone may benefit from physical therapy. Special education and related services will be of benefit to children with this disorder. 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 genetic disorders in the future. This disease entry is based upon medical information available through September 1992. 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 22 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 NIH/National INstitute of Child Health and Human Development 9000 Rockville Pike Bethesda, MD 20892 (301) 496-5133 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. Pp. 394. DELETED RING CHROMOSOME 22 IN A MENTALLY RETARDED BOY: K.H. Gustavson, et al.; Clin Genet (April, 1986, issue 29(4)). Pp. 337-41. RING CHROMOSOME 22: A CASE REPORT: C. Severien, et al.; Klin Padiatr (Nov-Dec, 1991, issue 203(6)). Pp. 467-9.