临床诊断为21羟化酶缺陷症患者的CYP21A2基因突变检出情况及不同突变患者的激素水平比较

Detection of CYP21A2 gene mutations and the differences in the levels of hormones in patients with 21-hydroxylase deficiency

目的:分析临床诊断为21羟化酶缺陷症(21-OHD)患者的CYP21A2基因突变检出情况,以明确临床诊断的准确率。方法:纳入2015年1月至2018年1月于北京协和医院就诊的514例21-OHD患者,年龄(15.6±11.8)岁,其中男164例,女350例,收集其临床和生化资料。提取外周血白细胞DNA,利用PCR扩增加Sanger测序方法和多重连接探针扩增技术(MLPA)检测CYP21A2基因的突变情况。根据基因检测结果将患者进行分组,两个CYP21A2等位基因均检出突变为A组,仅1个等位基因检出突变为B组,未检出CYP21A2基因突变的为C组,比较各组患者激素水平的差异。结果:514例患者中,401例(78.0%)患者的两个CYP21A2等位基因均检出致病突变,90例(17.5%)仅1个等位基因检出致病突变,23例(4.5%)未检出致病突变。不同临床表型的患者CYP21A2基因突变检出率差异无统计学意义。男性患者中,临床表现为单纯男性化型的A和B组患者血总皮质醇水平分别为0.04(0.02,0.20)nmol/L和0.24(0.17,0.28)nmol/L,A组低于B组,差异有统计学意义(P=0.014)。女性患者中,临床表现为失盐型的A、B和C组患者17-羟孕酮(17-OHP)分别为153.7(90.1,204.5)nmol/L、38.2(31.0,183.3)nmol/L和42.6(27.8,48.1)nmol/L,A组高于B组和C组,差异均有统计学意义(均P<0.05);临床表现为单纯男性化型的A、B和C组的孕酮水平分别为57.8(34.4,110.2)nmol/L、63.6(31.4,110.8)nmol/L和23.0(8.6,33.2)nmol/L,C组低于A组和B组,差异均有统计学意义(均P<0.05);临床表现为非经典型的A、B和C组患者17-OHP水平分别为158.7(59.1,187.6)nmol/L、147.8(131.9,179.3)nmol/L和24.5(20.4,54.2)nmol/L,C组低于A组和B组,差异均有统计学意义(均P<0.05)。结论:部分临床诊断为21-OHD的患者并未能检出两个CYP21A2等位基因的突变,表明其他引起17-OHP水平升高的先天性肾上腺皮质增生症(CAH)类型有被误诊为21-OHD的可能,基因检测对于CAH不同类型的鉴别诊断起到重要作用。

Objective To analyze the detection of CYP21A2 gene mutations in 21-hydroxylase deficiency(21-OHD)patients,so as to determine the accuracy of clinical diagnosis.Methods Totally,514 patients with 21-OHD who visited Peking Union Medical College Hospital from January 2015 to January 2018 were enrolled and their clinical and biochemical data were collected.DNAs were extracted from peripheral blood leukocytes and CYP21A2 mutations were detected by Sanger sequencing and multiple ligation probe amplification(MLPA)technique.We divided 514 patients into three groups:two mutations of CYP21A2 alleles(group A),one mutation of CYP21A2(group B),and no mutation of CYP21A2(group C).Results Mutation was detected in each allele of CYP21A2 gene in 401(78.0%)patients,ninety(17.5%)had only one mutant allele and 23(4.5%)had no mutation.There was no significant difference between the patients with different clinical phenotypes and the number of CYP21A2 gene mutations detected.In male,the cortisol of the patients with simple virilizing 21-OHD in group A[0.04(0.02,0.20)nmol/L]was lower than that of group B[0.24(0.17,0.28)nmol/L]and the difference was statistically significant(P=0.014).In female,17-hydroxyprogesterone(17-OHP)of patients with salt wasting 21-OHD in group A[153.7(90.1,204.5)nmol/L]was higher than that of group B[38.2(31.0,183.3)nmol/L]and C[42.6(27.8,48.1)nmol/L]and the differences were statistically significant(both P<0.05).The progesterone of patients with simple virilizing 21-OHD in group C[23.0(8.6,33.2)nmol/L]was lower than that of gourp A[57.8(34.4,110.2)nmol/L]and B[63.6(31.4,110.8)nmol/L]and the difference were statistically significant(both P<0.05).The 17-OHP of patients with non-classical 21-OHD in group C[24.5(20.4,54.2)nmol/L]was lower than that of group A[158.7(59.1,187.6)nmol/L]and B[147.8(131.9,179.3)nmol/L].The difference were statistically significant(both P<0.05).Conclusions Mutations of two alleles have not been found in all patients with clinically diagnosed 21-OHD.Other congenital adrenal hyperplasia(CAH)types which can cause similar changes in 17-OHP and other hormones may be misdiagnosed as 21-OHD.Therefore,21-OHD cannot be diagnosed with help of 17-OHP level only,and gene detection plays a vital role in the differential diagnosis of different CAH types.