Single nucleotide polymorphisms of the factor IX gene for linkage analysis in the southern Chinese population

Abstract

Summary. Carrier detection and prenatal testing for haemophilia B in Oriental populations have been hampered by the lack of informative markers within the factor IX (FIX) gene. We detected a T/C nucleotide variation at nucleotide 32770 in the poly-A region of the FIX gene in the mother of a haemophilia B child. Analysis of 139 unrelated alleles revealed a heterozygosity rate of 0´193, thus offering an additional marker for linkage analysis. Together with two other polymorphic sites (5 H MseI and 3 H HhaI) found in Chinese and Thai populations, these polymorphisms were useful in 66% of the families studied.