基因诊断先天性肾上腺皮质增生症1例报道 Diagnosis a Congenital Adrenal Hyperplasia Case by Genetic Testing

背景：先天性肾上腺皮质增生症(congenital adrenal hyperplasia, CAH)是一组因类固醇激素生物合成过程中某种酶先天性缺乏引起的常染色体隐性遗传病。临床上可表现为失盐、脱水、外生殖器性别不清、生长过速和典型的激素异常，易漏诊或误诊。常见多种酶缺陷，其中以21-羟化酶缺失症最常见，占该病的90%~95%。不同类型的鉴别依赖于激素水平测定及基因型分析。目前对先天性肾上腺皮质增生症的诊断可直接进行基因诊断。方法：对临床1例典型的21-羟化酶缺陷引起的失盐型CAH患儿进行相关基因检测。结果：患儿存在CYP21A2大片段基因缺失。结论：CYP21A2是失盐型CAH的致病基因，CYP21A2基因的缺失是失盐型CAH发病的根本原因。 Background: Congenital adrenal hyperplasia is one kind of autosomal recessive diseases, which is caused by lack of some kind of steroid hormone biosynthesis enzymes congenital. The clinical manifestation are such as salt loss, dehydration, ambiguous genitalia indistinguishable, quickly growth speed and the typical hormonal abnormalities, which lead to easily misdiagnosed. There are a variety of enzyme defect in this diseases, but 21-hydroxylase deficiency is the most common, accounting for 90% - 95%. We analyse different types relying on the hormone levels and genotype identification. At present, the diagnosis of congenital adrenal hyperplasia can be directly carried out by gene diagnosis. Methods: We detect the CAH-related gene of a neonate who is a typical 21-hydroxylase (salt-losing type) patient. Results: The neonate loses a large fragment of CYP21A2. Conclusions: CYP21A2 is a causative gene of salt-losing type of CAH, and deletion of CYP21A2 gene is the fundamental reason of salt-losing type of CAH in the pathogenesis.