先天性肾上腺皮质增生症(congenital adrenal hyperplasia，CAH)是一种常染色体隐性遗传病，在不同类型的CAH发病率中，11β-羟化酶缺乏症排第二位，该疾病的发生与人8号常染色体上CYP11B基因突变有关。本研究采集了1名14岁患者的外周血，通过提取基因组DNA，应用全外显子测序对其进行了基因检测，对疑似变异进行Sanger测序验证，并分析其特点。结果发现，患者CYP11B1基因第8外显子存在c.1226C>T纯合错义突变，导致其编码蛋白第409位丝氨酸突变为苯丙氨酸(p.Ser409Phe)，从而影响血红素与酶的结合，最终导致CYP11B1酶活性丧失，引起一系列临床症状。这一突变目前尚未见国内外有相关报道。本研究丰富了CYP11B1基因变异谱，为进一步研究11β-羟化酶缺乏症的致病机制提供了临床资料和遗传资源。

Congenital adrenal hyperplasia (CAH) is an autosomal recessive hereditary disease, and the 11β- hydroxylase deficiency is the second most common syndrome in different types of CAH. The occurrence of 11β- hydroxylase deficiency is related to the mutation of CYP11B gene on human autosome 8. In this report, we detected the gene mutation sites of a 14-year-old patient with 11β-hydroxylase deficiency by whole exon sequencing (WES), verified the suspected mutation by Sanger sequencing, and analyzed its characteristics. Gene sequencing revealed that homozygous missense mutation of c.1226C>T appeared on the 8th exon of CYP11B1 gene, which resulted in the mutation of the encoding protein Ser409 to phenylalanine (p. Ser409Phe), affecting the binding of heme and enzyme and resulting in the loss of CYP11B1 enzyme activity and a series of clinical symptoms. This mutation has not been reported at home and abroad. This case enriches the variation spectrum of CYP11B1 gene and provides clinical data and genetic resources for further research on the pathogenesis of 11β-hydroxylase deficiency.