Structure of new mutations in 2 STR systems.

Isolated father/child mismatches in cases with a high probability of paternity (W > 99.9%) have been investigated using short tandem repeat (STR) systems. According to the high probability of paternity new mutations could be assumed in these cases. A new mutation could be observed in 3 cases using the STR system HumACTBP2. Two of these cases showed a deletion and 1 case an insertion of 1 repeat (AAAG-motif) which could be verified by sequencing. In another paternity case a new mutation--1-repeat insertion (TCTA-motif)--in the HumVWA system was detected and verified by sequencing. These findings led to a new mutation rate of 0.7% (n = 453 meioses) for HumACTBP2 and 0.2% for HumVWA (n = 484 meioses).