Occasionally, bleeding reported by patients is out of proportion to his or her clotting factor level, suggesting that the mutation of the Factor VIII (hemophilia A) or Factor IX (hemophilia B) gene has altered not only the level of factor in circulation, but also its function. Therefore, it might be important to know exactly where the mutation is occurring (change in the gene leading to the altered function of the factor protein).
Since there are several hundred different mutations known for Factor VIII and almost as many for Factor IX. To identify a hemophilia patient’s or carrier’s individual mutation, the whole Factor VIII gene or Factor IX gene may have to be interrogated (sequenced). Mutation analysis can only be done in specialized laboratories.
In addition to determination of carriers' clotting factor activity status, we offer chromosomal gene mutation analysis to identify the specific gene mutation for Factor VIII or Factor IX. Both tests are important to determine carrier status and move forward with family planning.
Sons whose mothers are carriers of a hemophilia mutation have a 50% chance to inherit the affected X chromosome and develop hemophilia. Daughters of carrier mothers have a 50% chance of becoming carriers themselves. If males with hemophilia or female carriers wish to minimize the risk of passing on hemophilia to the next generation, we provide genetic counseling and discuss individualized options for family planning.
Options include gender selection, prenatal diagnosis, and preimplantation genetic diagnosis (PGD). With PGD, the carrier’s eggs are harvested after hormonal stimulation, and a diagnosis of hemophilia is made in the embryo after in-vitro fertilization. Non-affected embryos will subsequently be implanted and carried to term. We provide these services in collaboration with Reproductive Partners – UCSD Regional Fertility Center.
For more information on diagnosing carrier status and option for family planning, call the Hemophilia and Thrombosis Treatment Center at 619-471-0335, Monday to Friday, 8:30 a.m. to 4:30 p.m.