New FACTOR IX linked marker alleles in African Haemophilia B patients.

Three markers, one restriction length polymorphism (RFLP) (MseI) and two microsatellite markers (Intron 1 and 3'UTR), linked to the FACTOR IX gene, were assessed for the purpose of genetic testing for Haemophilia B families in South Africa. This was carried out using seven Haemophilia B families and fifty random control samples. We observed five new alleles for the Intron 1 marker within the black control and patient sample groups, and informativity in 89% (8/9) of all carrier females for at least one of the three markers observed. These markers are useful for carrier detection and prenatal diagnosis of Haemophilia B in the great majority of South African black and white families.