The following information may help to address your question:
What is trisomy 13?
is a type of chromosome disorder
characterized by having 3 copies of chromosome
13 in cells
of the body, instead of the usual 2 copies. In some affected people, only a portion of cells contains the extra chromosome 13 (called mosaic
trisomy 13), whereas other cells contain the normal chromosome pair.
Trisomy 13 causes severe intellectual disability
and many physical abnormalities, such as congenital heart defects
; brain or spinal cord abnormalities; very small or poorly developed eyes (microphthalmia); extra fingers or toes; cleft lip with or without cleft palate
; and weak muscle tone (hypotonia
). Most cases are not inherited
and result from a random error during the formation of eggs or sperm in healthy parents.
Due to various life-threatening medical problems, many infants with trisomy 13 do not survive past the first days or weeks of life.
Last updated: 3/17/2016
What are the signs and symptoms of trisomy 13?
Trisomy 13 is associated with severe intellectual disability and physical abnormalities in many parts of the body. People with this condition often have congenital heart defects
, brain or spinal cord abnormalities, very small or poorly developed eyes (microphthalmia), extra fingers and/or toes (polydactyly
), cleft lip or palate
, and decreased muscle tone (hypotonia).
Many infants with trisomy 13 fail to grow and gain weight at the expected rate (failure to thrive); have severe feeding difficulties; and episodes in which there is temporary cessation of spontaneous breathing (apnea).
Other features or trisomy 13 may include:
Last updated: 9/3/2015
What are the genetic changes related to trisomy 13?
Most cases of trisomy 13 result from having three copies of chromosome 13
in each cell in the body instead of the usual two copies. The extra genetic material
disrupts the normal course of development, causing the characteristic features of trisomy 13.
Trisomy 13 can also occur when part of chromosome 13 becomes attached (translocated) to another chromosome during the formation of reproductive cells (eggs and sperm) or very early in fetal development. Affected people have two normal copies of chromosome 13, plus an extra copy of chromosome 13 attached to another chromosome. In rare cases, only part of chromosome 13 is present in three copies. The physical signs and symptoms in these cases may be different than those found in full trisomy 13.
A small percentage of people with trisomy 13 have an extra copy of chromosome 13 in only some of the body's cells. In these people, the condition is called mosaic trisomy 13. The severity of mosaic trisomy 13 depends on the type and number of cells that have the extra chromosome. The physical features of mosaic trisomy 13 are often milder than those of full trisomy 13.
Last updated: 1/20/2015
How might trisomy 13 be treated?
Treatment for trisomy 13 depends on the affected person's signs and symptoms, and is generally symptomatic and supportive.
Surgeries are generally withheld for the first few months of life because of the high mortality rate associated with trisomy 13. Parents and medical personnel must carefully weigh decisions about extraordinary life-prolonging measures against the severity of the neurological and physical defects that are present and the likelihood of post-surgical recovery or prolonged survival.
Last updated: 9/3/2015
What is the long-term outlook for people with trisomy 13?
Trisomy 13 involves multiple abnormalities, many of which are life-threatening. More than 80% of children with trisomy 13 do not survive past the first month of life. For those that do survive, complications are common and may include:
- Breathing difficulty or lack of breathing (apnea)
- Feeding problems
- Heart failure
- Vision problems
People with trisomy 13 who survive infancy have severe intellectual disability and developmental delays, and are at increased risk for cancers.
Last updated: 9/3/2015
Where can I learn more about living with trisomy 13?
Information and supportive resources for trisomy 13 can be obtained from the organizations supporting this disease. Click on the "Organizations" link on our information page on trisomy 13
to view supporting organizations and contact information.
Last updated: 12/23/2016
We hope this information is helpful. We strongly recommend you discuss this information with your doctor. If you still have questions, please
GARD Information Specialist
Please see our Disclaimer.