Trisomy 13 (Patau Syndrome) Support Group

Patau syndrome, also known as trisomy 13, is a chromosomal aberration, a disease in which a patient has an additional chromosome 13 due to a non disjunction of chromosomes during meiosis. Like all non disjunction diseases (Down Syndrome, Edward Syndrome, etc...) the risk of disease in the offspring increases with maternal age at pregnancy.

Patau syndrome is associated with severe mental retardation, small eyes that may exhibit a split in the iris (coloboma), a cleft lip and/or palate, weak muscle tone (hypotonia), an increased risk of heart defects, skeletal abnormalities, and other medical problems. Affected individuals rarely live past infancy because of the life threatening medical problems associated with this condition. Patau syndrome affects approximately 1 in 10,000 live births. The risk of having a child with Patau syndrome increases as a woman gets older.

People with Patau syndrome 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 Patau syndrome.

Most cases of Patau syndrome result from trisomy 13, which means 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 called mosaic Patau syndrome.