The value of variable number of tandem-repeat polymorphisms in cases of disputed paternity not resolved by conventional markers: two case reports.

Disputed paternity cases are routinely tested in the authors' laboratory for red cell antigen, plasma protein, red cell enzyme, and HLA polymorphisms. This report concerns two cases in which the above test results made exclusion of paternity doubtful. In one case, exclusion of paternity was based on one discrepancy in the Duffy blood group system only, a unique situation in the investigators' experience of more than 2500 cases; the investigators were, therefore, reluctant to use this as the only evidence of exclusion. In the other case, it was necessary to postulate the presence of a rare haplotype, MSu, in the MNS blood group system to explain paternity. It was therefore decided to investigate allelic variable number of tandem-repeat (VNTR) DNA polymorphisms in these disputed paternity trios. VNTR DNA typing convincingly excluded these accused men from paternity.