Trisomy 13

While most cases of trisomy 13 occur randomly, a few cases are due to the presence of a translocation involving chromosome 13 in a parent. Parents who are at risk to have a translocation due to their family history can have a blood test called a karyotype, which can determine if a translocation is present.

Prenatal testing or screening (such as maternal blood screening, fetal ultrasound, chorionic villus sampling, or amniocentesis) is also available to determine if a current pregnancy is at risk for, or is affected by, trisomy 13 or other chromosome disorders.

People with a family history of trisomy 13 who are interested in learning about genetic screening or testing for themselves or family members are encouraged speak with a genetic counselor or other genetics professional.

The first step in deciding whether your children will need testing for a balanced translocation involving chromosome 13 is completing testing on yourself and your husband. The type of testing typically completed is a blood test called a karyotype, which can look at the structure of the chromosomes and determine if a translocation is present. This type of testing is usually completed by a genetics professional. 

If either of you have a balanced translocation involving chromosome 13, there is a chance your children could have inherited it. If either of your children inherited a balanced translocation involving chromosome 13, testing could be useful in making reproductive decisions. 

To find a medical professional who specializes in genetics, you can ask your doctor for a referral or you can search for one yourself. Online directories are provided by GeneTests, the American College of Medical Genetics, and the National Society of Genetic Counselors. If you need additional help, contact a GARD Information Specialist. You can also learn more about genetic consultations from Genetics Home Reference.