Complex variability of intron 40 of the von Willebrand factor (vWF) gene.

Intron 40 of the von Willebrand factor (vWF) gene exhibits a highly variable region of about 0.65 kb, which contains 5 juxtaposed STRs. We sequenced 0.65 kb amplicons from 68 chromosomes and found 2 frequent indel polymorphisms and 5 SNPs. The 68 chromosomes investigated here presented a total of 47 different haplotypes. Regarding the SNP allele distribution in our sample, we arranged our results of the vWF intron 40 into a system of 3 haplotypes, i.e. haplotypes a, b and c. Our review may be valuable in further optimising vWF typing in forensic applications and in avoiding pitfalls. Further attempts to develop sophisticated techniques may soon enable haplotyping using autosomale STR clusters.

DXS10079, DXS10074 and DXS10075 are STRs located within a 280-kb region of Xq12 and provide stable haplotypes useful for complex kinship cases.

The evaluation of the short tandem repeat (STR) markers DXS10079, DXS10074 and DXS10075 was amended to establish a STR cluster spanning a genetic distance<1 cM. These three STRs are located within a 280-kb region at Xq12 and provide stable haplotypes useful for solving complex kinship cases. Theoretically, this cluster could give rise to 2,548 different haplotypes in the German population and the genotyping of 781 men revealed the presence of 172 haplotypes. Since the three STRs were shown to be in strong linkage disequilibrium (LD), haplotype frequencies cannot be computed on the basis of a single locus allele frequency alone but have to be estimated directly. Here, we present data on linkage, haplotype frequencies and LD in a German population. Further clusters from other regions of the X chromosome will be published in the future to cover the chromosome with a well-structured network of highly informative sites.