Single and double incompatibility at vWA and D8S1179/D21S11 loci between mother and child: implications in kinship analysis.

BACKGROUND

Two cases of paternity dispute, examined with 17 autosomal short tandem repeats signified a possible single and double maternal mismatch at vWA and D8S1179/D21S11 loci in the children under investigation.

METHODS

Seventeen autosomal STR loci were analyzed using AmpFlSTR Identifiler, PowerPlex 16 kits. Six STR markers on X chromosome were amplified and analyzed. Mutated alleles were amplified, cloned in pCR(R)II-Topo vector, sequenced and investigated.

RESULTS

In case S1 the vWA locus indicated an allele mismatch with the mother. All the vWA alleles on amplification, cloning and sequencing depicted an increase of 2 repeats in the child. In case D1 maternal child inconsistency at D8S1179 and D21S11 loci was observed. The alleles were amplified, cloned and sequenced to analyze the repeat structure. Increase of 1 repeat in D8S1179 locus and an insertion mutation in D21S11 locus between the mother and questioned child were confirmed. A complete match with the 17 autosomal loci of the father and 6 X chromosome STR loci of the mother was observed in both the cases.

CONCLUSION

This is the first report of a maternally transmitted single mismatch at vWA locus and double mismatch at D8S1179 and D21S11 loci due to increase/mutation of the repeat in the paternity DNA testing. The results of nucleotide sequencing and STR analyses convincingly established that the suspected father and the mother are undeniably the biological parents of the questioned child.