A new strategy for prenatal diagnosis in a sporadic haemophilia B family

Although the quality of life for haemophiliacs has clearly improved in the last few years, haemophilia still remains a serious disorder justifying prenatal diagnosis (PD) and, if necessary, termination. Because chorionic villus sampling (CVS) is performed in the first trimester of pregnancy, an increasing number of carriers are interested in this test. It has been shown that waiting for the results is particularly distressing for pregnant women, therefore decreasing the diagnostic procedure time can be psychologically helpful. Here we report on PD in a sporadic haemophilia B family based on the direct identification of the pathogenic mutation in a CVS taken at the 12th gestational week. In order to hasten the results, we recovered DNA from a single villus fragment boiled in water and used it directly for PCR reaction. Conformation-sensitive gel electrophoresis (CSGE) was used to detect the mutation in the haemophilia carrier and in the foetus. This approach allowed us to obtain a diagnosis within 24 h of CVS, thus avoiding the long-term psychological effects on the pregnant woman.