Concurrent Mutations at D21S11 and Penta D Loci in a Paternity Testing Case

Abstract In a case of paternity testing, out of the 39 autosomal short tandem repeats (STRs) system tested, two loci (Penta D and D21S11) were simultaneously inconsistent with paternity. Five other STR kits (PowerPlex®21, Goldeneye® 17X, AGCU 17 + 1, Microreader™ 23sp and Microreader™ 21sp ID System) were utilized to review the genotypes of them. The result showed that genotypes of all STR loci accord with the Mendel's law, excepting for Penta D and D21S11. Clone sequencing was further performed to reveal the underlying reason of these mutations. The sequence results showed that a two-step mutations and 6 nucleotides insertion (TATCTA) nearby repeat region were found in Penta D and D21S11 respectively. Although, it is a rare phenomenon that two mutations were happened in the same chromosome concurrently. But once encountered, various kits and sequencing technology contribute to finding the truth for accurate conclusion.