Trisomy 13 (also called Patau syndrome) is a genetic disorder in which a person has three copies of genetic material from chromosome 13, instead of the usual two copies. Rarely, the extra material may be attached to another chromosome (translocation).
Trisomy 13 occurs when extra DNA from chromosome 13 appears in some or all of the body's cells.
Trisomy 13 -- the presence of an extra (third) chromosome 13 in all of the cells.
Trisomy 13 mosaicism -- the presence of an extra chromosome 13 in some of the cells.
Partial trisomy -- the presence of a part of an extra chromosome 13 in the cells.
The extra material interferes with normal development.
Trisomy 13 occurs in about 1 out of every 10,000 newborns. Most cases are not passed down through families (inherited). Instead, the events that lead to trisomy 13 occur in either the sperm or the egg that forms the fetus.
More than 90% of children with trisomy 13 die in the first year.
Complications begin almost immediately. Most infants with trisomy 13 have congenital heart disease.
Complications may include:
Breathing difficulty or lack of breathing (apnea)
When to Call a Medical Professional
Call for an appointment with your health care provider if you have had a child with trisomy 13 and you plan to have another child. Genetic counseling can help families understand the condition, the risk of inheriting it, and how to care for the patient.
Trisomy 13 can be diagnosed before birth by amniocentesis with chromosome studies of the amniotic cells.
Parents of infants with trisomy 13 that is caused by a translocation should have genetic testing and counseling, which may help them avoid having another child with the condition.
Summar K, Lee B. Cytogenetics. In: Kliegman RM, Stanton BF, St. Geme JW III, Shor NF, Behrman RE, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 76.
Chad Haldeman-Englert, MD, FACMG, Wake Forest School of Medicine, Department of Pediatrics, Section on Medical Genetics, Winston-Salem, NC. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Bethanne Black, and the A.D.A.M. Editorial team.