Genetic Testing: What It Can Provide for You and Your Family
Genetic testing of the factor VIII and factor IX genes is available for individuals who have hemophilia A and hemophilia B. Genetic testing analyzes the factor VIII or factor IX gene in order to identify the genetic variant (i.e., change) in the gene which is preventing the gene from producing clotting factor properly and therefore causing hemophilia. Genetic testing involves taking a blood sample and sending it to a lab that is equipped to perform this type of testing. This information is important for a couple of reasons:
- For some individuals with hemophilia, this can provide additional information about what their chance is to develop an inhibitor, which may change their health care management
- Once the disease-causing variant in the factor VIII or factor IX gene is identified, in an individual with hemophilia, accurate carrier testing can be offered to his female family members in order to determine if they are carriers of hemophilia
Carrier testing is available to find out whether females with a family history of hemophilia are carriers. Genetic testing is the most accurate method of carrier testing. Carrier testing using factor levels alone is not accurate, as some female carriers have normal factor levels. This can lead to individuals being given inaccurate information about whether they are a carrier.
Carrier testing is essential for early diagnosis and treatment of children with hemophilia. Women with a family history of hemophilia should consider carrier testing if they:
- Would like to be tested to determine their carrier status, either for healthcare reasons and/or to know if they could pass it on to their children
- Want to consider reproductive options such as preimplantation genetic diagnosis or prenatal testing to determine whether a male fetus has hemophilia
For more information about the genetic testing that is available and additional topics such as insurance coverage, cost, what the information will provide your specific family, how to pursue testing, and reproductive options, please contact the IHTC genetic counselors.