法医学杂志

法医学杂志 ›› 2018, Vol. 34 ›› Issue (4): 396-400.DOI: 10.12116/j.issn.1004-5619.2018.04.011

• 案例分析 • 上一篇    下一篇

疑似Amelogenin等位基因丢失的检测与分析12例

毕  洁1，畅晶晶2，余纯应1   

  1. 1. 北京明正司法鉴定中心，北京 100070； 2. 公安部物证鉴定中心，北京 110000
  • 发布日期:2018-08-25 出版日期:2018-08-28
  • 作者简介:毕洁（1983—），女，主检法医师，主要从事法医物证学鉴定；E-mail：bijie0403@163.com

Detection and Analysis of 12 Suspected Amelogenin Allelic Loss Cases

BI Jie1, CHANG Jing-jing2, YU Chun-ying1   

  1. 1. Beijing Mingzheng Forensic Identification Center, Beijing 100070, China; 2. Institute of Forensic Science, Ministry of Public Security, PRC, Beijing 110000, China
  • Online:2018-08-25 Published:2018-08-28

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摘要： 目的 观察并分析亲权鉴定案件中Amelogenin等位基因丢失的案例，探讨Amelogenin等位基因丢失的类型、机制以及对性别鉴定的影响和应对方法。 方法 选择经SiFaSTRTM 23plex DNA身份鉴定系统检测，女性出现Amelogenin X的峰面积与相邻杂合子峰面积一致或低于相邻纯合子峰面积的1/2，男性出现Amelogenin X丢失的样本，进行X-STR分型及Amelogenin X测序，同时对出现Amelogenin Y丢失的男性样本，检测Y-STR分型及Y染色体性别决定区（sex-determining region of Y，SRY）进行验证。统计Amelogenin等位基因丢失的类型及丢失率，分析出现变异的机制及影响。 结果 1例男性Amelogenin X等位基因丢失，经测序证实为引物结合区突变；4例女性疑似Amelogenin X等位基因丢失，经测序证实出现引物结合区突变的仅为1例。7例男性出现Amelogenin Y丢失，其中SRY阳性5例，SRY阴性2例。5例SRY阳性案件中4例可检出部分Y-STR分型，1例未检出Y-STR分型，2例SRY阴性案件均未检出Y-STR分型。Amelogenin等位基因丢失率约为0.029%。 结论 Amelogenin X丢失不影响性别判定，Amelogenin Y丢失可能对性别造成误判，需要检测Y-STR或SRY来明确性别，对于未检出Y-STR分型且SRY检测为阴性的“男性”，建议进行染色体核型分析及性别分化相关基因检测以进一步明确性别。

关键词: 法医遗传学, 釉原蛋白质, 等位基因丢失, Y染色体性别决定区, 性别决定, 亲子鉴定, 案例分析

Abstract: Objective To observe and analyse the Amelogenin allelic loss in parent-child identification cases, and to explore the type and mechanism of Amelogenin allelic loss as well as its influence on gender identification and solutions. Methods After the detection by SiFaSTRTM 23plex DNA identification system, samples had the characteristics of the peak area of Amelogenin X was the same as the one of adjacent heterozygote or lower than one half of adjacent homozygote in females while Amelogenin X loss was observed in males were selected. X chromosome STR （X-STR） typing and Amelogenin X sequencing were performed. The samples with Amelogenin Y loss in males were confirmed by the detection of Y chromosome STR typing and sex-determining region of Y （SRY）. The type and rate of Amelogenin allelic loss were confirmed and calculated, and the mechanism and influence of this variation were also analysed. Results Amelogenin X allelic loss was observed in one male sample, the mutation in primer-binding region was confirmed by sequencing. The suspected Amelogenin X allelic loss was observed in four female samples, but the mutation in primer-binding region was confirmed by sequencing in only one sample. Amelogenin Y allelic loss was observed in seven male samples, SRY positive cases was detected in five of them, and two were SRY negative. Y-STR type was detected in four cases of the five SRY positive cases, which was not detected in the two SRY negative cases. The rate of Amelogenin allelic loss was about 0.029%. Conclusion Amelogenin X allelic loss does not affect the gender identification, but Amelogenin Y allelic loss may cause wrong gender identification. Thus, Y-STR or SRY should be detected for gender confirmation. When Y-STR genotypes are not detected in a “male” whose SRY detection is also negative, then the chromosome karyotype analysis and sex differentiation related genes test should be taken to further confirm the gender.

Key words: forensic genetics, amelogenin, allelic loss, sex-determining region of Y, sex determination, paternity identification, case analysis