A novel missense mutation in the factor VIII gene identified by analysis of amplified hemophilia DNA sequences.

To date the only point mutations demonstrated to cause hemophilia are C to T transitions in TaqI sites. These were detected by screening Southern blots with cloned factor VIII probes. During the development of improved methods for detecting and analyzing mutations in genomic DNA, a novel G to C transversion mutation has been identified. This rare transversion results in a missense mutation, with proline being substituted for arginine in one of the active domains of the factor VIII molecule. The results suggest that the improved methods will be useful for detecting mutations in hemophilia as well as in other genetic disorders. In this method, specific DNA sequences in genomic DNA are amplified using oligonucleotide primers and a heat-resistant DNA polymerase. Mutations are detected and localized in the amplified samples by RNase A cleavage, and the altered region is then sequenced.