Identification of a novel Tru9 I polymorphism in the human vitamin D receptor gene

We found a novel Tru9 I restriction polymorphism in intron 8 of the vitamin D receptor (VDR) gene in healthy French Caucasians. It corresponds to a su bstitution of A for G at nucleotide +443 bp from the end of exon 8. The all elic frequency of G and A in 151 unrelated subjects was 0.894 and 0.106, re spectively. This polymorphism is located in the reverse primer binding site of primers that have been frequently used in the literature to genotype a BsmI restriction polymorphism. The presence of the Tru9I A allele may resul t in allele drop-out when the BsmI restriction fragment length polymorphism (RFLP) is genotyped with the original set of primers. This novel Tru9I pol ymorphism may be useful for analysis of the VDR gene.