男性个体Amelogenin基因座异常分型的分析OACHSSCD

Objective To investigate the abnormal genotyping and its causes at the Amelogenin locus in male samples.Methods A total of 23 647 blood samples from unrelated male individuals were ana-lyzed using the STRtyper-21G kit,and 38 samples with abnormal Amelogenin locus were identified.These samples were retested and classified using GlobalFilerTM and PowerPlex® 21 kits.Additional sex chromosome STR genotyping and Sanger sequencing were performed for samples with abnormal geno-types.Sequence-tagged site(STS)testing was conducted for samples suspected of Amel-Y microdele-tions.Results Among above 38 samples,except for Amelogenin locus,all samples showed normal male sex chromosome STR typing.The detection rate of abnormal genotyping was 0.161%(38/23 647),which were categorized into three major types.Among them,30 cases had Amel-X deletion:5 cases had C→T mutation at position 372;2 cases had G→A mutation at position 293;23 cases had A→G mutation at position 304.There were 2 cases of Amel-Y deletion:1 case of insertion mutation of TTAA at position 387,and 1 case of microdeletion of the short arm containing Amel-Y.Six cases of abnormal Amel-X/Y peak ratios were identified:using the STRtyper-21G kit,the abnormalities ap-peared as low Amel-X with absent Amel-Y,normal Amel-X with absent Amel-Y,normal Amel-X with low Amel-Y,respectively.However,retesting with GlobalFilerTM and PowerPlex® 21 kits consistently showed normal Amel-X with low Amel-Y.The GlobalFilerTM profiling showed that the peak heights of Amel-Y were comparable to those of the Y-InDel and DYS391 markers,and no abnormalities were de-tected by sequencing.Conclusion Amelogenin genotyping abnormalities occur at a measurable fre-quency in the population and are mainly associated with mutations,which can be categorized as Amel-X deletion,Amel-Y deletion,and Amel-X/Y peak ratio abnormality.Regarding normal Amel-X peaks with lower Amel-Y peaks,the possibility of mosaic loss of chromosome Y(mLOY)in samples,which is commonly observed in elderly males,should be considered and given attention.