Prenatal Diagnosis of Hemophilia A and B

Hemophilia A and B are inherited X-linked recessive bleeding disorder caused by deficiency of coagulation factor VIII (FVIII) or FIX. These are the most common hereditary hemorrhagic disorders known. These are globally distributed and hence are not limited by ethnicity or geographical borders. Both the disorders lead to life-threatening and often disabling condition. There have been major advances in molecular therapy in the last few decades which have improved the treatment for Hemophilia. But, still a lot needs to be done in this area in developing countries. Patients with Hemophilia rarely live beyond childhood in these countries. Hence, prenatal diagnosis aided by carrier detection is used extensively for the prevention of affected hemophilic child in developing countries. The diagnosis can be done using the direct method of mutation analysis or the indirect method of linkage analysis in the respective FVIII or FIX gene. Prenatal diagnosis of hemophilia A or B is possible by means of chorionic villus biopsy in the first trimester which traces the mutation or informative genetic markers. Today chorionic villus sampling is the most widely used method but amniotic fluid, fetal blood and pre-implantation genetic diagnostics can also be used in selected cases. Prenatal diagnosis must be preceded by adequate genetic counseling and risk assessment of the potential carrier and subsequent support during the diagnostic process.