先天性肾上腺皮质增生症21-羟化酶缺陷的产前诊断

目的对21-羟化酶缺乏症患儿及父母的CYP21A2基因进行突变分析。方法收集2015年1月-2017年12月就诊于柳州市妇幼保健院的3个家系中21-羟化酶缺乏症患儿及父母的外周血,运用广州丰华有限公司的时间分辨荧光免疫分析仪(time-resolved fluoroimmunoassay,TRFIA)联合Southern测序、多重连接探针扩增技术(MLPA)分析CYP21A2基因的所有外显子及其两端侧翼序列,并通过对父母的基因型进行验证,为有效进行产前诊断提供科学依据。结果 3个家系中共检出3种突变,分别为CYP21A2基因c.293-13C﹥G突变纯合子、c.518C﹥G复合c.737delA突变、c.293-13AG突变纯合子,均为CYP21A2基因外显子1-3缺失;2例产前诊断胎儿为携带者,1例产前诊断胎儿为c.293-13AG突变纯合子;父母均为携带。结论采用时间分辨荧光免疫分析方法(time-resolved fluoroimmunoassay,TRFIA)联合Southern测序、多重连接探针扩增技术(MLPA)可以同时检测出CYP21A2基因的突变和缺失,是先天性肾上腺皮质增生症21-羟化酶缺陷产前诊断的可靠方法。     

21-羟化酶缺乏症家系的基因突变研究

目的通过对3个21-羟化酶缺乏症家系的21-羟化酶基因(steroid21-hydroxylase gene,CYP21)直接测序研究,探讨家系中该基因突变类型。方法收集4例患者及其部分家系成员外周血,提取基因组DNA,PCR扩增CYP21基因后直接测序。结果CYP21基因序列分析共检测到6种突变类型。家系1中患者CYP21基因存在4种杂合突变:clusteE6、Q318X、A391T、P459H,其中前3种突变串联排列于同一条染色体上,P459H突变目前国内外尚未见报道,A391T为罕见突变;家系2中患者CYP21基因存在clusteE6、R483W两种杂合突变,其中R483W为罕见突变类型;家系3中患者第4外显子存在I172N纯合突变。结论在3个21-羟化酶缺乏症家系中共检测出6种突变类型,其中P459H为新发现的突变,A391T、R483W为罕见突变。虽然导致21-羟化酶缺乏症的突变主要是一些从假基因(CYP21P)转位到CYP21的序列,但随机突变也是21-羟化酶缺乏症的原因。     

21-羟化酶缺陷症基因诊断方法的建立及应用

目的 建立21-羟化酶缺陷症的基因诊断方法并评价其临床应用价值.方法 收集9例肾上腺皮质增生症患儿血样,采用全长基因直接测序法分析21-羟化酶编码基因CYP21A2的点突变,同时采用多重连接依赖探针扩增技术和位点特异性PCR-酶切多态分析大片段的CYP21A2基因缺失或(和)转换突变.同时对患儿的双亲也进行了基因检测.结果 9例患儿共发现点突变5种,分别为IVS2 13A/C＞G(9个等位基因)、p.Arg356Trp(1个等位基因)、Cluster E6(1个等位基因)、p.Gln318X(1个等位基因)和Prom cony(1个等位基因).除Prom conv不能明确其功能外,其它4种均为致病突变.检测到的基因缺失或(和)转换突变有两种,一种为大片段缺失,导致CYP21A2基因单拷贝缺失,共发现3例患者(3个等位基因),另一种为CYP21A2基因重排后形成的CYP21 A1 P/CYP21A2嵌合基因,共发现3例患者(3个等位基因),并应用建立的基因诊断方案确定了全部患者的基因型.所有的突变均遗传自亲代.结论 建立了21-羟化酶缺陷症的基因诊断方法.该方法不仅能特异性地检测点突变,而且能够检测大片段的缺失或(和)转换突变,因此具有较高的临床应用价值.     

胎儿脐血17-羟孕酮检测用于先天性肾上腺皮质增生症的产前筛查研究新进展

正先天性肾上腺皮质增生症(congenital adrenal hyperplasia,CAH)是一组因肾上腺皮质激素合成过程中酶缺陷引起的疾病,属常染色体隐性遗传[1]。常见的酶主要有21-羟化酶、11β-羟化酶、17α-羟化酶、18-羟化酶、3β-羟类固醇等,其中最常见的为21-羟化酶缺乏(21-hydroxylase deficiency,21-OHP),占CAH的90%~95%[2]。1病因及发病机制在类固醇激素合成过程中,21-羟化酶催化17-羟孕酮(17-OHP)转化为脱氧皮醇,以及催化为脱氧皮质酮,这些甾体激素分别转化为皮质醇(cortisol)和醛固酮     

先天性肾上腺皮质增生症患者21-羟化酶基因启动子区域突变的初步研究

目的研究先天性肾上腺皮质增生症（ｃｏｎｇｅｎｉｔａｌａｄｒｅｎａｌｈｙｐｅｒｐｌａｓｉａ,ＣＡＨ）患者２１－羟化酶基因启动子区域的突变。方法用ＰＣＲ、ＳＳＣＰ、内切酶酶谱分析及测序分析方法对１２例ＣＡＨ患者的２１－羟化酶基因启动子区域进行研究。结果１２例患者中有６例出现异常ＳＳＣＰ条带,其中１例在ＣＫ－２（－１０１）结合区域内的ＫｐｎⅠ内切酶识别位点及其－２０１处的ＴａｑⅠ内切酶识别位点存在突变,并经测序证实。结论在ＣＡＨ患者－２１羟化酶基因启动子区域存在突变,可能为ＣＡＨ发病机理之一。     

先天性肾上腺皮质增生症CYP21A2基因突变的研究

目的了解肾上腺皮质增生症患儿CYP21A2基因突变热点,并分析其基因型和表型的关系。方法对在新生儿常规遗传代谢性疾病17α-羟孕酮(17-αOHP)筛查后高危并经临床诊断为阳性的14例干血片标本及其父母样本,采用SNaPshot方法联合PCR-特异性测序技术对中国人群常见的17个突变热点进行一次性基因分型检测。结果共检出5种CYP21A2基因突变类型,最常见的为IVS2-13A/CG(42.9%)和1069 CT(42.9%);单纯男性化型患儿518 TA突变检出率为7.1%;955 CT突变检出率为14.3%;1294 GA突变检出率为7.1%。14例阳性干血片标本患者及其父母样本SNaPshot技术和测序技术的结果完全吻合,共有3例复合纯合/杂合突变,7例单纯合突变,2例杂合突变,2例正常,显示SNaPshot技术高度的特异性和灵敏度。结论采用SNaPshot技术检测CYP21A2基因具有高通量、准确、对样本容受性高的特点,便于临床应用,揭示了基因型和临床表型的一致性。     

一种新复合杂合突变导致21-羟化酶缺陷症

目的探讨1例单纯男性化型21-羟化酶缺陷症(21-OHD)基因突变的类型和特点及临床表型与基因突变类型之间的关系。方法收集患者的临床资料,提取外周血白细胞DNA,用PCR方法扩增CYP21A2基因的10个外显子及内含子边界,测序鉴定CYP21A2基因突变位点,进一步分析突变位点与临床表型的关系。结果患者的临床表现主要为外阴发育异常。基因测序结果显示为复合杂合突变,其一个等位基因为c.515 T>A,p.I172N,另一个等位基因为c.593 T>G,p.L198X,此种复合杂合突变主要引起单纯男性化表现。p.L198X是至今尚未见报道的一种新突变。结论发现了CYP21A2基因一种新的突变p.L198X,丰富了CYP21A2基因突变数据库。同时从分子遗传学方面证实了对患者的诊断,患者基因型能很好地解释其临床表现。     

先天性肾上腺皮质增生基因定位的细胞遗传学证据

21-羟化酶位点的缺陷会导致先天性肾上腺皮质增生(CAH),这是一种常染色体隐性遗传病。Dupont等(1977)证实了编码此酶的位点与主要组织相容性复合物(MHC)基因是连锁的。Levine等(1978)将21-羟化酶位点定位子靠近HLA-B位点的区域。CAH中最常见的类型是由21-羟化酶缺陷所引起的,这种缺陷是点突变的结果,但是这个基因复合物区域的染色体缺失或易位也将会妨碍此酶的产生。在一个CAH基因     

应用PCR／ASO探针技术分析21羟化酶B基因两个突变位点

应用ＰＣＲ／ＡＳＯ探针技术检测了１２例无血缘关系的先天性肾上腺皮质增生症患儿的２１羟化酶功能基因Ｂ的ＣＤ１７２Ｉｌｅ→Ａｓｎ和ＣＤ３１８Ｇｌｎ→０两种突变类型，发现在１２例ＣＡＨ患儿中７例携带ＣＤ１７２突变，患儿均属单纯男性化型，其中１例为该突变纯合子，６例为杂合子，计算得该突变占所分析的ＣＹＰ２１－Ｂ基因总数的３３．３％（８／２４）；而ＣＤ３１８突变的发生率较低，只检出１例男性化伴失盐型患儿为此     

CYP21基因启动子结构功能及突变研究进展

21羟化酶基因 (CYP2 1基因 )缺陷可引起 2 1羟化酶缺乏。近年对CYP2 1基因的研究取得了一定进展 ,本文介绍了该基因启动子区的位置、结构、调节因子 ,重要功能域及突变等方面的进展 ,从分子水平进一步加深了对CAH的发病机理的了解     

Ethnic-specific distribution of mutations in 716 patients with congenital adrenal hyperplasia owing to 21-hydroxylase deficiency

Congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency (21OHD) occurs worldwide. The most common mutations in the CYP21A2 gene in 716 unrelated patients were analyzed and the mutations were grouped by ethnicity, as defined through self-declaration corroborated by review of pedigrees extending to two or three generations. Prevalent allelic mutations and genotypes were found to vary significantly among ethnic groups, and the predominance of the prevalent mutations and genotypes in several of these populations was significant. There are ethnic-specific mutations in the CYP21A2 gene. A large deletion is prevalent in the Anglo-Saxons; a V281L (1685 G to T) mutation is prevalent in Ashkenazi Jews; an R356W (2109 G to A) mutation is prevalent in the Croatians; an IVS2 AS -13 (A/C to G) mutation is prevalent in the Iranians and Yupik-speaking Eskimos of Western Alaska; and a Q318X (1994 C to T) mutation is prevalent in East Indians. Genotype/phenotype non-correlation was seen when at least one IVS2 AS -13 (A/C to G) mutation in the CYP21A2 gene was present.     

Mutations in Steroid 21-Hydroxylase (CYP21)

The inherited inability to synthesize cortisol is termed congenital adrenal hyperplasia. More than 90% of cases are caused by 21-hydroxylase deficiency. This syndrome is characterized by signs of androgen excess and often mineralocorticoid deficiency. Steroid 21-hydroxylase (P450c2l) is a microsomal enzyme expressed in the adrenal gland that catalyzes conversion of 17-hydroxyprogesterone and progesterone to 11-deoxycortisol and deoxycorticosterone respectively. In man, this enzyme is encoded by the CYP21 (CYP21B) gene which is located in the HLA major histocompatibility complex along with a pseudogene, CYP21P (CYP21A). Mutations in CYP21 causing congenital adrenal hyperplasia are almost all generated by recombinations between CYP21 and CYP21P. These recombinations either delete CYP21 or transfer deleterious mutations from CYP21P to CYP21, a process termed apparent gene conversion. The degree of enzymatic compromise caused by each mutation is correlated with the clinical severity of the deficiency observed in patients carrying that mutation. © 1994 Wiley-Liss, Inc.     

CYP21 mutations and congenital adrenal hyperplasia

Congenital adrenal hyperplasia (CAH) is a common autosomal recessive disorder caused mainly by defects in the steroid 21-hydroxylase (CYP21) gene. More than 90% of CAH cases are caused by mutations of the CYP21 gene on chromosome 6p21.3. The wide range of CAH phenotypes is associated with multiple mutations known to affect 21-hydroxylase enzyme activity. To date, 56 different CYP21 mutations have been reported, mostly point mutations, but small deletions or insertions have been described too, as well as complete gene deletions. Fifteen mutations, constituting 90-95% of alleles, are derived from intergenic recombination of DNA sequences between the CYP21 gene and the highly homologous CYP21P pseudogene, while the remaining are spontaneous mutations. A reliable and accurate detection of CYP21 mutations is not only important for clinical diagnosis, but also for carrier detection as there is a high variability in the basal level of 17-hydroxyprogesterone between normal and heterozygous individuals. Several strategies based on polymerase chain reaction (PCR)-driven amplification with allele-specific oligonucleotides to the CYP21 gene have been developed. It has been demonstrated that one reaction for PCR amplification of the CYP21 gene and the chimeric CYP21P/CYP21 gene using mixed primers in combination with nested PCR and single-strand conformation polymorphism is considered highly efficient and accurate for molecular diagnosis of CAH due to 21-hydroxylase deficiency.     

Characterization of novel missense mutations in <Emphasis Type="Italic">CYP21</Emphasis> causing congenital adrenal hyperplasia

Congenital adrenal hyperplasia due to 21-hydroxylase deficiency is the most common inherited disorder of steroid metabolism, with an incidence of 1/10,000 in the general Caucasian population. Although most patients carry a deletion of the CYP21 gene or any of nine pseudogene-derived point mutations, the number of reported rare mutations continues to increase, and consist today of more than 80 different point mutations. In this study, we report the characterization of four additional missense mutations in CYP21. Two of these, L166P and A391T, are novel missense mutations, whereas the R479L and R483Q mutations have been detected previously. Functional assays of mutagenized CYP21 were performed in transiently transfected mammalian cells in vitro, and enzymatic ability of substrate conversion of the two natural substrates of CYP21-17-hydroxyprogesterone and progesterone-was determined. All mutants displayed reduced in vitro enzyme activities compared with wild type, but to different extents, corresponding to clinical phenotypes that span the whole spectrum of disease severity. Functional studies are important to further establish the relationships between genotype and clinical phenotype as well as in vitro CYP21 activity in congenital adrenal hyperplasia due to 21-hydroxylase deficiency. This has relevance for diagnosis, prognosis, and genetic counseling for affected families.     

Clinical report of testicular hypoplasia combined with 21-hydroxylase deficiencyCSCD

Objective: To investigate the correlation of 21-hydroxylase deficiency (21-OHD) with male testicular dysplasia. Methods: Clinical data of 8 infertile males with congenital adrenal hyperplasia due to 21-OHD was retrospectively analyzed. In addition, potential mutations of the CYP21A2 gene was detected. Results: All patients were referred because of azoospermia or severe oligospermia and had small testis with averaged testicular volume of 6.1 mL. Three patients had testicular adrenal rest tumors. Endocrinologic examinations revealed low levels of leutinizing hormone and follicular stimulating hormone, normal or elevated testosterone, elevated progesterone, elevated or normal adrenocoticotropic hormone, and low or normal Cortisol. All patients had adrenal cortical hyperplasia, 5 with adrenal adenoma, 1 case associated with bilateral adrenal myelolipoma. All patients were given glucocorticoid replacement therapy for 3 to 6 months, which successfully improved the seminal status of 6 patient and resulted pregnancies in 5 couples. Seven pathogenic mutations of the CYP21A2 gene among the 8 patients. Conclusion: 21-OHD can cause testicular hypoplasia and spermatogenic failure. Glucocorticoids and operations can obtain good result and improve spermatogenesis. Our results have shown a good genotype/phenotype correlation in these cases. All patients have carried the p. Ilel72Asn mutation, which is associated with simple virilizing form. © 2018 West China University of Medical Sciences. All rights reserved.     

Screening of CYP21 gene mutations in 129 French patients affected by steroid 21-hydroxylase deficiency

The frequency of 12 different mutations of the steroid 21-hydroxylase gene (CYP21) was investigated in 129 French patients affected by congenital adrenal hyperplasia (CAH) due to steroid 21-hydroxylase deficiency. Eighty-nine percent of the CAH chromosomes were characterized. The most frequent mutations were a C-G substitution in intron 2, the deletion of the CYP21 gene and a T-A substitution in exon 4 in the severe form of the disease, and a G-T substitution in exon 7 in the nonclassic form. The correlation between the genotypes and the clinical forms of the disease showed marked variation in the phenotype from a single genotype, suggesting that individual variation and undetected additional mutations on the same CAH chromosome accounted for the phenotype. In 65 informative meioses of CAH families, no de novo mutation was found. © Wiley-Liss, Inc.     

Genetic diagnosis of 21‐hydroxylase deficiency: DGGE‐based mutation scanning of CYP21

Congenital adrenal hyperplasia (CAH) due to 21‐hydroxylase deficiency is caused by mutations in the gene CYP21 encoding the enzyme steroid 21‐hydroxylase. In addition to deletions, approximately 20 different point mutations have been reported, and still novel mutations are detected. This makes genetic diagnosis as well as carrier detection of 21‐hydroxylase deficiency a complicated matter. We developed a simple nonradioactive assay based on the polymerase chain reaction (PCR) in combination with denaturing gradient gel electrophoresis (DGGE) to screen for mutations in the CYP21 gene. DGGE allows a fast scanning of PCR‐amplified segments of genes for the presence or absence of any single base pair alterations. We have performed this technique on the coding sequence and intron‐exon junctions of CYP21. Our results emphasize that this procedure constitutes a fast and reliable approach when performing diagnosis of 21‐hydroxylase deficiency. Hum Mutat 13:385–389, 1999. © 1999 Wiley‐Liss, Inc.     

Identification of non-amplifying CYP21 genes when using PCR-based diagnosis of 21-hydroxylase deficiency in congenital adrenal hyperplasia (CAH) affected pedigrees

Steroid 21-hydroxylase deficiency is among the most common inborn errors of metabolism in man. Characterization of mutations in the 21- hydroxylase gene (CYP21) has permitted genetic diagnosis, facilitated by the polymerase chain reaction (PCR). The most common mutation is conversion of an A or C at nt656 to a G in the second intron causing aberrant splicing of mRNA. Homozygosity for nt656G is associated with profoundly deficient adrenal cortisol and aldosterone synthesis, secondary hypersecretion of adrenal androgens, and a severe form of congenital adrenal hyperplasia (CAH) characterized by ambiguous genitalia and/or sodium wasting in newborns. During the course of genetic analysis of CYP21 mutations in CAH families, we and others have noticed a number of relatives genotyped as nt656G homozygotes, yet showing no clinical signs of disease. A number of lines of evidence have led us to propose that the putative asymptomatic nt656G/G individuals are incorrectly typed due to dropout of one haplotype during PCR amplification of CYP21. For prenatal diagnosis, we recommend that microsatellite typing be used as a supplement to CYP21 genotyping in order to resolve ambiguities at nt656.      

Identification of CYP21 mutations,one novel,by single strand conformational polymorphism (SSCP) analysis

Congenital adrenal hyperplasia due to 21‐hydroxylase deficiency is a common autosomal recessive disorder (MIM# 201910) due to mutations in the 21‐hydroxylase (CYP21) gene (GDB Accession # M12792). Using our protocol for single strand conformational polymorphism (SSCP) analysis, we have identified two mutations not known to exist in the 21‐hydroxylase pseudogene (CYP21P). One mutation involving codon 169, TGC to AC appears to be novel. The 46,XX patient carried the codon 169 mutation on her paternal allele and a large gene deletion/conversion event on her maternal allele. This patient had been referred in the immediate neonatal period for the evaluation of genital ambiguity and had developed hyponatremia and hyperkalemia. The second patient presented with premature pubic hair. She carried R356Q on her maternal allele and V281L on her paternal allele. © 1998 Wiley‐Liss, Inc.