A novel mutation at the AMEL primer binding region on the Y chromosome in AMELY negative male

Abstract

Gender identification in forensic DNA typing is an important tool for criminal investigation as well as STR typing. Most methods are based on a size difference of amelogenin X and Y (AMELX and AMELY). There have been some reports that the method by amelogenin (AMEL) incorrectly typed some males as females because the AMELY allele is not detected. AMELY allele dropout is often caused by deletions encompassing AMELY on Yp11.2 and accompanied with Y-STR allele dropout (especially DYS458). However, an unusual deletion was found in our laboratory. The AMELY allele could be recovered by using another commercial kit and alternative AMEL primer sets, and the Y-STR markers resulted in a complete profile. Sequencing results showed that there was an 8bp deletion in AMELY at the position corresponding to 41-48bp downstream from the 3' end of the 6bp deletion site in AMELX. This is considered a novel mutation at a primer binding region.