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目的 探讨中国人先天性尿道下裂的发生与５α还原酶２（ Ｓ Ｒ Ｄ５ Ａ２） 基因突变及 Ｓ Ｒ Ｙ 基因突变的关系。方法 收集先天性尿道下裂患儿静脉血２３ 例，抽提 Ｄ Ｎ Ａ。经 Ｐ Ｃ Ｒ 分别扩增 Ｓ Ｒ Ｄ５ Ａ２ 基因的第１ 至第５ 外显子及 Ｓ Ｒ Ｙ 基因的 Ｄ Ｎ Ａ 片段。对各扩增片段采用单链构象多态性诊断法（ Ｐ Ｃ Ｒ Ｓ Ｓ Ｃ Ｐ） ，筛选基因突变标本，有电泳异常的标本进行测序分析。结果 经 Ｐ Ｃ Ｒ Ｓ Ｓ Ｃ Ｐ 发现３ 例 Ｓ Ｒ Ｄ５ Ａ２ 基因的第４ 外显子 Ｄ Ｎ Ａ 扩增片段电泳带位置异常，经 Ｄ Ｎ Ａ 序列分析证实２ 例为纯合子型第２２７ 位密码子由 Ｃ Ａ Ａ 替代 Ｃ Ｇ Ａ（ Ａｒｇ２２７ Ｇｌｎ） ；１ 例为双重杂合子型突变，第２２７ 位密码子由 Ｃ Ａ Ａ 替代 Ｃ Ｇ Ａ，同时第１８６ 位密码子由 Ｔ Ｔ Ｇ 替代 Ｔ Ｔ Ｔ（ Ｐｈｅ１８６ Ｌｅｕ） 。 Ｐ Ｃ Ｒ Ｓ Ｓ Ｃ Ｐ 检测 Ｓ Ｒ Ｙ 基因片段未发现异常电泳带。结论 Ｓ Ｒ Ｄ５ Ａ２ 基因突变，可能是先天性尿道下裂的病因之一， Ｓ Ｒ Ｄ５ Ａ２ 基因的第２２７ 位密码子可能为中国人该基因的突变热点，而尿道下裂中 Ｓ Ｒ Ｙ 基因的突变少见。
Objective To investigate the relationship between the occurrence of congenital hypospadias and the mutation of 5α-reductase 2 (S R D5 A2) gene and S R Y gene in Chinese. Methods Twenty-three patients with congenital hypospadias were enrolled in this study. The first to the fifth exons of the S R D5 A2 gene and the D N A fragment of the S R Y gene were respectively amplified by P C R. Single-strand conformation polymorphism (P C R-S S C P) was used to amplify the amplified fragments. The mutated samples were screened and the samples with abnormal electrophoresis were sequenced. Results The DNA fragment of the fourth exon D N A of exon 4 of S R D5 A2 gene was found to be abnormal in P C R S S C P, and 2 cases of homozygous type 227 The codon for C A A was replaced by C A A (Arg227 Gln); one was a double heterozygous mutation with C A A at C 227 and the C 186 at C 186, while the 186th codon was replaced by T T G T T T (Phe186 Leu). P C R S S C P detected S R Y gene fragments found no abnormal electrophoresis band. Conclusions S R D5 A2 gene mutation may be one of the causes of congenital hypospadias. The 227th codon of S R D5 A2 gene may be a hot spot mutation in Chinese, and the S R Y gene in hypospadias The mutation is rare.