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Trisomy 13, also called Patau syndrome, is a chromosomal condition that is associated with severe mental retardation and certain physical abnormalities. These abnormalities include small eyes that may exhibit a split in the iris (coloboma), an opening in the roof of the mouth (a cleft palate) and/or a cleft lip, weak muscle tone (hypotonia), skeletal abnormalities, an increased risk of heart defects, and other medical problems. Affected individuals rarely live past infancy because of the life-threatening medical problems associated with this condition.
Trisomy 13 affects approximately 1 in 10,000 newborns. The risk of having a child with trisomy 13 increases as a woman gets older.
Trisomy 13 is related to chromosome 13.
People with trisomy 13 have additional DNA from chromosome 13 in some or all of their cells. The extra material disrupts the normal course of development, causing the characteristic features of trisomy 13.
Most cases of trisomy 13 result when each cell in the body has three copies of chromosome 13 instead of the usual two copies. A small percentage of cases occur when only some of the body's cells have an extra copy of chromosome 13, resulting in a mixed population of cells with a differing number of chromosomes. Such cases are sometimes called mosaic trisomy 13.
Trisomy 13 can also occur when part of chromosome 13 becomes attached to another chromosome (translocated) before or at conception. Affected people have two copies of chromosome 13, plus extra material from chromosome 13 attached to another chromosome. With a translocation, the person has a partial trisomy for chromosome 13 and often the physical signs of the syndrome differ from those typically seen in trisomy 13.
Most cases of trisomy 13 are not inherited, but occur as random events during the formation of reproductive cells (eggs and sperm). An error in cell division called nondisjunction results in reproductive cells with an abnormal number of chromosomes. For example, an egg or sperm cell may gain an extra copy of chromosome 13. If one of these atypical reproductive cells contributes to the genetic makeup of a child, the child will have an extra chromosome 13 in each cell of the body.
Mosaic trisomy 13 is also not inherited. It occurs as a random error during cell division early in fetal development. As a result, some of the body's cells have the usual two copies of chromosome 13, and other cells have three copies of the chromosome.
Translocation trisomy 13 can be inherited. An unaffected person can carry a rearrangement of genetic material between chromosome 13 and another chromosome. This rearrangement is called a balanced translocation because there is no extra material from chromosome 13. Although they do not have signs of trisomy 13, people who carry this type of balanced translocation are at an increased risk of having children with the condition.
'''Chromosome 15q trisomy''' is an extremely rare genetic disorder, caused by a chromosomal aberration in which there is an excess copy of the long ("q") arm of human chromosome 15. The disorder is also known as '''Distal Duplication 15q''' and '''Partial Duplication 15q Syndrome'''. The disorder is primarily characterized by stunted growth, mental retardation, and distinctive malformations of the head (anatomy) and face. Additional abnormalities may involve malformation of the skeleton, vertebral column and neck; fingers and/or toes; genitals (particularly in males); and, in some cases, heart problems.
Dr. Greene's HouseCalls - A discussion of medical information on trisomy, trisomy 13, genetics, and his own personal family experience with this rare disease.
Down Syndrome (Trisomy 21) - Explains the cardiac and non-cardiac complications, as well as outlining treatment options and prognosis. From the Cincinnati Children's Hospital Medical Center.
Down Syndrome Association of Western Australia - Works to support the community to develop the potential of people with Down syndrome (Trisomy 21) to live a valued life.
Trisomy 21 Online Community - For all those touched by people with all three forms of Trisomy 21. Community includes message forums, chat room, information for parents who have just found out their child has Trisomy 21, pictures and many other information pages and links.
Chromosome 22 Central - Support group for families who have children with any chromosome 22 disorder, including trisomies, cat eye syndrome, translocations, deletions 22q11, 22q13, VCFS, Digeorge syndrome, rings and unique malformations.
S.O.F.T. - A United Kingdom support organisation for parents of infants with Trisomy 13 and 18 and other related disorders.
S.O.F.T. - Support Organization in the United States for Trisomy 18, 13, and other related disorders. Provides literature, conferences, newsletter, chapter information, and international contacts.
Distal Trisomy 10q Families - Support for families of children with Distal Trisomy 10q. Family stories, contacts, other information.
Trisomy 18 Moms - A place to list your Trisomy 18, Edwards syndrome memorial site , get help making a website, to share your unique story via the web.
Trisomy 18 Angel - This site was made in memory of our daughter Abigail Renee, to help other families who have been given a diagnosis of Trisomy 18.