Department of Forensic Medicine, Zhongshan School of Medicine, Sun Yat-sen University, No.74 Zhongshan Road II, Guangzhou, 510089, People's Republic of China.
Int J Legal Med. 2012 Jul;126(4):513-8. doi: 10.1007/s00414-011-0594-1. Epub 2011 Jul 7.
The use of amelogenin locus typing as a gender marker incorporated in short tandem repeat (STR) multiplexes is a common practice in sex typing. Mutations in the X or Y homologue of the amelogenin gene can be misleading and result in serious mistakes in forensic applications and prenatal diagnosis. In these present studies, the amelogenin gene of 8,087 unrelated male individuals from Chinese Han population was genotyped with Powerplex(®)16 system. The samples that showed discordant results were taken for frequency calculation and further validated by re-amplification with different primer sets, Y-STR typing, and sequencing. Our results describe six amelogenin X-allele (AMELX) or amelogenin Y-allele (AMELY) null cases in these studied subjects with an overall prevalence of 0.074%. Further validation revealed point mutations in the amelogenin-priming sites associated with AMELX nulls (three cases, 0.037%) and deletions on the Y chromosome encompassing the AMELY and other Y-STR loci with three AMELY nulls (0.037%). These mutations and failure of the amplification of the AMELX and AMELY alleles have not been reported for the Chinese population. These and previous findings suggest that mutations in the amelogenin gene may result in amplification failure of the AMELX or AMELY allele, and an additional gender test for unambiguous sex determination may be needed.
使用 amelogenin 基因座分型作为性别标记物，并将其纳入短串联重复（STR）多重扩增中，是性别分型的常见做法。X 或 Y 同源 amelogenin 基因的突变可能会产生误导，并导致法医应用和产前诊断中的严重错误。在这些研究中，对来自中国汉族的 8087 名无关男性个体的 amelogenin 基因进行了 Powerplex(®)16 系统基因分型。对显示不一致结果的样本进行了频率计算，并通过使用不同引物组、Y-STR 分型和测序进行了进一步验证。我们的结果描述了在这些研究对象中，有 6 例 amelogenin X-等位基因（AMELX）或 amelogenin Y-等位基因（AMELY）缺失，总体发生率为 0.074%。进一步验证显示，与 AMELX 缺失相关的 amelogenin 引物结合位点存在点突变（3 例，0.037%），以及 Y 染色体上包含 AMELY 和其他 Y-STR 基因座的缺失，导致 3 例 AMELY 缺失（0.037%）。这些突变和 AMELX 和 AMELY 等位基因的扩增失败在中国人群中尚未报道过。这些发现以及以前的研究表明，amelogenin 基因的突变可能导致 AMELX 或 AMELY 等位基因的扩增失败，可能需要进行额外的性别测试以明确性别鉴定。
