Examination of method to detect silent allele on D19S433 locus

DOI: 10.3408 / jafst.766 ) In the Japanese population, D19S433 silent allele is rarely detected in cases of testing with commercial STR kits. The silent allele causes inconsistency of STR typing results between kits and false negative parentage despite the true biological parentage. The cause of this problematical mismatch is reported that the mutation is a base change ( G ＞ A ) 32 nucleotides downstream from the 3 ′ end of the AAGG repeats ( G32A ) , so reverse primer in STR kits fail to anneal to the binding site, con-sequently no STR peak or extremely low peak is detected. In this study, volunteers originated from 4 silent-allelic pedigrees are examined whether the silent allele was judged by AmpFlSTR Identiˆler Plus PCR ampliˆcation kit, PowerPlex Fusion system, and GlobalFiler PCR ampliˆcation kit, furthermore they carry G32A mutation or not by direct sequencing, SNaPshot genotyping, and TaqMan genotyping. In conclusion, it has been identiˆed that all silent-allelic peaks are caused by G32A mutation and followed by Mendelian genetics. Actually, some factors in‰uence the for-mation of silent allele, such as primer binding ˆdelity, improvement of other PCR reagents, and PCR cycle conditions. When the suspected silent-allelic peak appears, additional tests with multiple STR kits which containing