目的 探讨5α-还原酶2缺乏症的临床表型与基因型特点。 方法 回顾分析5例5α-还原酶2缺乏症患儿的 临床资料，分析临床表型与基因型之间的关联性。 结果 5例患儿都表现为阴茎短小(3例类似阴蒂外观)，睾丸发育不良。 5例患儿人绒毛膜促性腺激素(hCG)激发后睾酮/双氢睾酮(T/DHT)比值 10.26~64.99。基因检测显示， 1例为纯合突变 c.680G?>?A， 4例为复合杂合突变；突变性质主要为错义变异，其次分别为缺失、重复、无义变异。 结论 5α-还原酶2缺 乏症的临床表型均有外生殖器发育异常，基因检测有助于疾病的诊断。

Objective To explore the correlation between phenotype and genotype of 5 α-reductase 2 deficiency. Methods The clinical data of five children with 5 α-reductase 2 deficiency were retrospectively analyzed and the relation between their clinical phenotype and genotype were analyzed. Results All of these five children presented small penis and testicular hypoplasia, three of whom had ones similar to the clitoris appearance. The testosterone/dihydrotestosterone (T/DHT) ratio was 10.26-64.99 after human chorionic gonadotropin (hCG) stimulation. Gene detection showed one case had c.680G > A homozygous mutation and the others were compound heterozygous mutations. The mutations were mainly missense mutations, followed by deletion, duplication and nonsense mutations. Conclusion The 5 α-reductase 2 deficiency has different degrees of abnormal genital development. Genetic testing contributed to the diagnosis of this disease.