Von Willebrand factor short sequence repeat locus 2 (intron 40) consists of three polymorphic subloci.
Currently, identification of alleles within the short sequence repeat locus (SSR locus) of intron 40 of the von Willebrand factor gene (previously known as VNTR II) is based on the size of PCR products that only predicts a certain number of repeats. Through cloning and sequencing, we demonstrated the complexity of nucleotide sequence structure of this region by describing three polymorphic tetranucleotide repeat subloci SSR 'a', SSR 'b' and SSR 'c' within the same originally described locus: the original TCTA (9-14 repeats), a small TCTA repeat locus (2 or 3 repeats) located at the 5' end and 30 nucleotides upstream from the original locus and a TGTA repeat locus (5 or 6 repeats), adjacent to the 2/3 repeat locus. Sequencing of 54 VWF alleles has revealed 14 different sequence combinations in this region while the size variability in the region only amounts to a 7-allele system. While the determination of VNTR alleles by PCR remains a practical methodology in linkage analysis, this may not be applicable in forensic medicine since not all alleles of identical length based on PCR are the same. Our study reveals the important implication of the identification of SSR 2 subloci and concludes that at least in some situations, there may be a necessity to take into consideration these polymorphic subloci.
Othman
Maha
M
Department of Pathology and Molecular Medicine, Queens University, Kingston, Canada.
Elbatarny
Hisham S
HS
Byrne
Christopher D
CD
O'Shaughnessy
Denise Frances
DF
D000483:Alleles; D001483:Base Sequence; D017124:Conserved Sequence; D006801:Humans; D007438:Introns / Q000235:genetics; D018895:Microsatellite Repeats / Q000235:genetics*; D016133:Polymerase Chain Reaction / Q000379:methods; D014841:von Willebrand Factor / Q000235:genetics*
D014841:von Willebrand Factor