RÉSUMÉ
The purpose of this study is to investigate the Sal I, Nru I and Mse I restriction fragment length polymorphisms (RFLPs) of factor IX gene in Chinese Han people. The frequencies of FIX-192 and FIX-793 for A and G, and FIX-698 for T and C were analyzed by polymerase chain reaction (PCR) in unrelated normal Chinese Han people. A sample of 214, 210 and 206 unrelated X chromosomes were analyzed for FIX-192 and FIX-793 and FIX-698, respectively. The results showed that the frequencies for FIX-192 were 0.878 for A and 0.122 for G, with a heterozygosity rate of 0.213, and the frequencies for FIX-793 were 0.552 for A and 0.448 for G, with a heterozygosity rate of 0.494, the frequencies for FIX-698 were 0.311 for T and 0.689 for C, with a heterozygosity rate of 0.429. It was concluded that the SalIand NruI and MseI RFLPs of FIX gene may be useful markers for carrier detection and prenatal diagnosis in Chinese families with hemophilia B patients.