Triallelic patterns in STR loci used for paternity analysis: Evidence for a duplication in chromosome 2 containing the TPOX STR locus

We report triallelic patterns in several short tandem repeat (STR) loci revealed by routine paternity testing using the commercial AMPFlSTR®Profiler™ and AMPFlSTR®SGMplus™ kits. One case where the TPOX-locus (2p25.3) produced three peaks from the blood sample of a child was analysed further. Quantitative polymerase chain reaction (QPCR) and STR typing of the DNAs of the family trio revealed a large (>1.59 Mb) duplication flanking the TPOX-locus in chromosome 2 in both the mother and child. The implications of such genetic anomalies for paternity testing are discussed.