摘要 该文检测了1例先天性肾上腺皮质增生症（CAH）小儿及其父母CYP21A2基因突变，复习该病的临床特征、治疗监测及分子遗传机制。采用QIAGEN Blood DNA Mini kit提取外周血DNA，根据CYP21A2基因与其假基因间的基因序列差异设计高特异性的PCR引物，用PrimeSTAR DNA聚合酶（TAKARA） 扩增CYP21A2基因全长，并对扩增产物进行直接测序，分析检测CYP21A2基因突变。 该患儿36 日龄，临床诊断为CAH（21-羟化酶缺乏失盐型），至1岁6个月龄进行了基因诊断证实。该先证者为CYP21第2内含子c.293-13C位点突变，先证者为纯合子，其父母均为杂合子。该病尽早确诊及规范治疗，可避免发生失盐危象，减少病死率；避免骨龄老化，改善成年终身高；避免成年后生育功能障碍。通过对CAH分子遗传机制的了解，可提高对该病的再认识，优化确诊方法；同时对于先证者家系的携带者诊断及遗传咨询具有重要的临床价值。
Abstract：CYP21A2 gene mutations in a child with congenital adrenal hyperplasia (CAH), and the child's parents, were detected in the study. The clinical features, treatment monitoring and molecular genetic mechanism of CAH are reviewed. In the study, DNA was extracted from peripheral blood samples using the QIAGEN Blood DNA Mini Kit; a highly specific PCR primer for CYP21A2 gene was designed according to the sequence difference between CYP2lA2 gene and its pseudogene; the whole CYP2lA2 gene was amplified with PrimeSTAR DNA polymerase (Takara), and the amplification product was directly sequenced to detect and analyze CYP2lA2 gene mutation. The child was clinically diagnosed with CAH (21-hydroxylase deficiency, 21-OHD) at the age of 36 days, and the case was confirmed by genetic diagnosis at the age of 1.5 years. The proband had a homozygous mutation at c.293-13C in the second intron of CYP21 gene, while the parents had heterozygous mutations. Early diagnosis and standard treatment of CAH (21-OHD) should be performed to prevent salt-wasting crisis and reduce mortality; bone aging should be avoided to increase final adult height (FAH), and reproductive dysfunction due to oligospermia in adulthood should be avoided. These factors are helpful for improving prognosis and increasing FAH. Investigating the molecular genetic mechanism of CAH can improve recognition and optimize diagnosis of this disease. In addition, carrier diagnosis and genetic counseling for the proband family are of great significance.
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