中国人原发性先天性青光眼患者CYP1B1基因突变分析

原发性先天性青光眼(primary congenital glaucoma,PCG),是一种严重危害儿童视力的致盲性眼病,与遗传有一定关系。为探讨中国人PCG与CYP1B1基因的关系,我们对7例PCG患者的CYP1B1基因进行分析,现报告如下。1材料与方法1.1病例收集在广州市儿童医院眼科就诊的表型为PCG的患者7例,抽取静脉血5mL,EDTA抗凝。所有标本间均无任何血缘关系。1.2主要试剂和仪器DNA抽提试剂盒、dNTPs、Taq酶(美国Fermentas公司),100bp DNA Markers、EB替代品(广州威佳公司)。采用Biometra UNOⅡ型PCR仪(德国Biometra公司)。1.3基因组DNA的制备按…     

原发性先天性青光眼CYP1B1基因变异初步研究

目的了解CYP1B1基因变异在中国原发性先天性青光眼(PCG)患者发病中的作用。方法收集来自不同地区的16例PCG患者,对其CYP1B1基因编码外显子进行直接测序,对照组进行单核苷酸多态性分析。结果在1例PCG患者中发现了一种变异,为8006G>A(R390H)。它是位于外显子III的错义突变。还发现了五种单核苷酸多态性,分别为3793T>G,R48G,A119S,A330S,V432L。结论CYP1B1基因是导致中国人PCG患者的致病基因,但也有其他变异可能和PCG变异有关。     

原发性先天性青光眼患者CYP1B1突变的研究

目的:了解原发性先天性青光眼患者致病基因CYP1B1(Cytochrome P450 family 1 subfamily B polypeptide 1)的变异情况.方法:采用高分辨率熔解(high-resolution melting,HRM)方法,分析20例原发性先天性青光眼患者的CYP1 B1基因热点突变区,同时采用测序的方法验证HRM的检测结果.结果:检出g.6767C＞T(p.D449D)变异2例,g.2527C＞G(p.R48G)变异1例,两种变异共存者1例.结论:在CYP1B1基因突变筛查方法中,HRM具有高度的灵敏性和特异性,可用于筛查原发性先天性青光眼.PCG的原因可能与g.6767C＞T(p.D449D)和g.2527C＞G(p.R48G)的变异有关;两种变异共存者可能导致更严重的PCG.     

CYP1B1突变与眼科疾病

细胞色素P4501B1（CYP1B1）是人体重要的代谢酶，本文从生化结构、细胞定位、遗传多态等方面对P4501B1基因（CYP1B1）进行了综述，并重点讨论了该基因的突变在原发性先天性青光眼、青少年型青光眼、Peters异常等眼病中的可能致病机制。     

原发性先天性青光眼的遗传学研究进展

原发性先天性青光眼作为严重威胁婴幼儿视力发育的眼病,其遗传倾向受到关注,目前GLC3A,GLC3B和GLC3C三个相关候选基因已经定位。CYP1B1是目前仅找到的先天性青光眼的致病基因,其突变和功能的研究成为热点。本文就先天性青光眼的分子遗传学研究进展及其与CYP1B1的关系作一综述。     

湖北地区原发性先天性青光眼患儿CYP1B1基因的新突变研究

目的探讨湖北地区汉族原发性先天性青光眼（PCG）患儿的基因突变情况并为基因诊断奠定基础。方法对47例无关个体PCG患儿及100例健康正常儿童进行基因分析。采取外周静脉血4ml,制备外周白细胞基因组DNA,参照文献所报道的引物序列,聚合酶链反应（PCR）分别扩增CYP1B1基因的第2、3外显子,琼脂糖凝胶电泳鉴定产物后,应用单链构象多态性（SSCP）、变性高效液相色谱分析（DHPLC）及DNA序列分析技术对患儿和对照组进行基因分析。结果7例PCG患儿呈现CYP1B1基因的第3外显子第385密码子的第1个碱基C→T碱基点突变,致对应的亮氨酸转变为苯丙氨酸（L385F）。这一变异在正常对照组成员中未检出,且检索国内外文献尚未见报道。结论湖北地区汉族PCG患者存在CYP1B1基因第3外显子突变,这一新突变位点位于P450蛋白的重要功能区,可能为病理性突变。在汉族PCG患者中进行CYP1B1基因突变的深入研究并寻找其他致病基因,对探讨PCG发病机制具有重要意义。     

CYP1B1基因缺失小鼠在高糖皮质激素环境下对青光眼的易感性

目的观察高浓度糖皮质激素对CYP1B1^-/-小鼠青光眼易感性的影响。方法采用成年CYP1B1^-/-小鼠作为实验模型,以同龄C57BL／6J小鼠作为对照。每3天结膜下注射0．04mL倍他米松,用Tonopen眼压（IOP）笔每周定期测定小鼠IOP,于第一次给药前,给药后4、8、12周分别摘除眼球,制备石蜡切片,光学显微镜下观察小鼠视网膜形态和厚度,采用TUNEL法检测视网膜神经节细胞（RGCs）的凋亡。结果与给药前相比,2组小鼠给药后4、8、12周的IOP均较前升高,差异有统计学意义（P〈0．05）;CYP1B1^-/-小鼠的IOP在给药后8周、12周较C57BL／6J小鼠显著升高,差异有统计学意义（P〈0．05）。随着倍他米松注射时间的推移,2组小鼠视网膜纤维层均变薄,各时间组的总体差异有统计学意义（P〈0．05）;且CYP1B1^-/-小鼠视网膜纤维层厚度在给药后8周、12周较C57BL／6J小鼠显著变薄,差异有统计学意义（P〈0．05）。2组小鼠RGCs凋亡的速度与给药前相比均显著增加,差异有统计学意义（P〈0．05）;且CYP1B1^-/-小鼠与C57BL／6J小鼠相比结果更为显著（P〈0．05）。结论在高浓度糖皮质激素的诱导下,CYP1B1^-/-小鼠对青光眼的易感性增加。     

点突变对RB1基因拚接区的影响

应用ＰＣＲ－ＳＳＣＰ（聚合酶链反应－单链构象多态）联合序列分析对视网膜母细胞瘤肿瘤组织ＲＢ１基因存在状态进行检测，以掌握视网膜母细胞瘤发生时确切的ＲＢ１基因突变类型及发生位置。除发现编码区内ＲＢ１基因点突变、缺失和插入改变外，尚发现成熟ｍＲ－ＮＡ拚接位点（ｓｐｌｉｃｅｄｏｎｏｒ）特有序列的点突变，ＲＢ１基因此种改变尚属少见。     

原发性先天性青光眼CYP1B1基因新变异

目的 探讨CYP1B1基因变异在湖南地区原发性先天性青光眼患者中的分布.方法 病例对照研究.收集来自湖南地区的13例原发性先天性青光眼患者的临床资料进行分析,对13例患者的CYP1B1基因编码外显子进行直接测序和聚合酶链反应-限制性内切酶技术检测.结果 13例原发性先天性青光眼患者中,有1例发现一种基因新突变(c.C319G,L107V),是位于外显子2的错义突变.100例正常人中未见L107V突变.同时发现已报道的4种单核苷酸多态位点,分别为R48G、A119S、V432L、D449D.结论 CYP1B1基因L107V突变可能是导致湖南地区原发性先天性青光眼患者的致病原因之一.     

原发性先天性青光眼分子遗传学研究进展

原发性先天性青光眼（primarycongenital aucoma,PCG）是一种发生于婴幼儿的遗传性致盲性眼病,也是先天性青光眼中最常见的类型,遗传因素为该病的主要致病原因,目前报道的与PCG相关的候选基因为CYPIBl、LTBP2和MYOC,并对这些基因的遗传方式、突变筛查及突变后的基因结构、功能改变等方面做了大量研究。然而,上述基因突变并不能解释所有PCG患者的发病机制,因此,发现新的致病基因和突变位点将成为研究工作者关注的焦点。f国际眼科纵览,2012,36：293—297）     

Compound heterozygous mutations in CYP1B1 gene leads to severe primary congenital glaucoma phenotype

AIM: To identify the novel mutation alleles in the CYP1B1 gene of primary congenital glaucoma (PCG) patients at Shandong Province of China, and investigate their correlation with glaucomatous features. METHODS: The DNA from the peripheral blood of 13 congenital glaucoma patients and 50 ethnically matched healthy controls from the affiliated hospital of Qingdao University were extracted. The coding region of the CYP1B1 gene was amplified by PCR and direct DNA sequencing was performed. Disease causing-variants were analyzed by comparing the sequences and the structures of wild type and mutant CYP1B1 proteins by PyMOL software. RESULTS: Two missense mutations, including A330F caused by c.988G>T&c.989C>T, and R390H caused by c.1169G>A, were identified in one of the 13 PCG patients analyzed in our study. A330F mutation was observed to be novel in the Chinese Han population, which dramatically altered the protein structure of CYP1B1 gene, including the changes in the ligand-binding pocket. Furthermore, R390H mutation caused the changes in heme-protein binding site of this gene. In addition, the clinical phenotype displayed by PCG patient with these mutations was more pronounced than other PCG patients without these mutations. Multiple surgeries and combined drug treatment were not effective in reducing the elevated intraocular pressure in this patient. CONCLUSION: A novel A330F mutation is identified in the CYP1B1 gene of Chinese PCG patient. Moreover, in combination with other mutation R390H, this PCG patient shows significant difference in the CYP1B1 protein structure, which may specifically contribute to severe glaucomatous phenotype.     

Two novel variants in CYP1B1 gene: a major contributor of autosomal recessive primary congenital glaucoma with allelic heterogeneity in Pakistani patients

AIM: To find the CYP1B1 mutations associated with primary congenital glaucoma (PCG) in Pakistani consanguineous pedigrees. METHODS: After getting informed consent, 11 consanguineous pedigrees belonging to different ethnic groups were enrolled. Detailed medical history was recorded and pedigrees were drawn. The standard ophthalmological examination was done to characterize the phenotype. Genomic DNA was extracted from 10 mL whole blood and coding exons and exon intron boundaries of CYP1B1 gene were directly sequenced. Bioinformatics tools were used to model the mutant protein and predict the effect of novel variants on protein structure and function. RESULTS: Sequencing analysis revealed 5 different CYP1B1 variants in 7 families (7/11; 64%), including two novel variants. A common mutation, p.R390H was found in four families, whereas p.P437L was found once in a family. Two novel variants, a homozygous non sense variant p.L13* and a compound heterozygous variant, p.P350T along with p.V364M were segregating with PCG in two families. All the patients had the variable onset and severity of the disease. The success rate of early clinical interventions was observed dependent on mutation types and position. Two different haplotypes were associated with frequently found mutation, p.R390H. CONCLUSION: Identification of novel CYP1B1 variants reassert the genetic heterogeneity of Pakistani PCG patients. The patients with missense mutations show severe phenotypic presentations and poor vision after surgical interventions as compare to patients with null variants. This may help to better understand the role of CYP1B1 mutations in the development of PCG and its course of pathogenicity.     

原发性先天性青光眼的分子遗传学研究新进展

原发性先天性青光眼(primary congenitalglauco—ma，PCG)是一种遗传性致盲眼病。其防治关键在于揭示PCG致病基因，实现基因诊断和治疗。近年来的分子遗传学研究确定CYPlBl基因为PCG致病基因之一。本文对CYPlBl基因突变及其遗传特点作一综述，旨在为进一步研究提供参考。     

Overview of Cytochrome P450 1B1 gene mutations in patients with primary congenital glaucoma

The objective of this study was to investigate the distribution of mutations in the Cytochrome P450 1B1 gene (CYP1B1) in patients with primary congenital glaucoma (PCG) among different populations. All identifiable original studies on CYP1B1 gene mutations of patients with PCG were reviewed. Finally, DNA mutations within the CYP1B1 gene were identified in 542 patients with PCG according to 52 scientific articles and 147 distinct mutations were found. The 3987G>A (G61E) missense mutation is a founder mutation in Middle Eastern population, responsible for 45.52% of CYP1B1 mutations. In Gypsies, missense mutation 7996G>A (E387K) seems to be a founder mutation, accounting for 79.63% of CYP1B1 mutations. It seems that there is no founder mutation in Asian or Caucasian population, but also accumulates in some spots. Mutations 7927G>A (V364M), 7990C>T (L385F) and 8006G>A (R390H) are common in Asian population. In Caucasians, 7940G>A (R368H), 8037dup10, 8006G>A (R390H), 7901del13, 4340delG, 3987G>A (G61E), 7996G>A (E387K), 4490G>A (E229K) and 8005C>T/A (R390C/S) are common mutations. The findings suggest that ethnic differences and the geographical distribution of PCG may be associated with different CYP1B1 mutation patterns. Such information may be useful in developing strategies for reliable clinical genetic testing of patients with PCG and their families.     

A Novel CYP1B1 Mutation with Congenital Glaucoma and Total Aniridia

Purpose: Primary congenital glaucoma is a common disorder in the Middle East mainly caused by mutations in the the CYP1Bl gene. We report a family with three siblings that presented with recalcitrant childhood glaucoma, aniridia in two siblings with a novel CYP1B1 gene mutation.

Materials and methods: Review of pedigree, clinical history and clinical course of the family. Genetic testing in the affected family members.

Results: Three sisters presented with clinical findings of severe congenital glaucoma and a positive family history. Clinical examination of two of sisters revealed corneal scarring, bilateral aniridia with severe glaucoma that required multiple surgical procedures to control intraocular pressure. The third sibling presented with garden-variety primary congenital glaucoma. Genetic analysis revealed a novel CYP1B1 gene mutation (g.8291 C?>?T; p.S485F).

Conclusion: CYP1B1 mutation related congenital glaucoma can present with an extreme form of anterior segment dysgenesis that includes recalcitrant glaucoma, corneal opacification and aniridia.     

Novel CYP1B1 mutations and a possible prognostic use for surgical management of congenital glaucoma

AIM: To identify CYP1B1 gene mutations and evaluate their possible role as a prognostic factor for success rates in the surgical management of Egyptian congenital glaucoma patients. METHODS: Totally 42 eyes of 29 primary congenital glaucoma patients were operated on with combined trabeculotomy/trabeculectomy with mitomycin-C and followed up at 1d, 1wk, 1, 6 and 12mo postoperatively. Genomic DNA was extracted from peripheral blood leukocytes. Coding regions of CYP1B1 gene were amplified using 13 pairs of primers, screened for mutations using single-strand conformation polymorphism followed by sequencing of both strands. Efficacy of the operation was graded as either a success [maintaining intraocular pressure (IOP) less than 21 mm Hg with or without anti-glaucoma medication], or a failure (IOP more than 21 mm Hg with topical antiglaucoma medications). RESULTS: Seven novel mutations out of a total of 15 different mutations were found in the CYP1B1 genes of 14 patients (48.2%). The presence of CYP1B1 gene mutations did not correlate with the failure of the surgery (P=0.156, odds ratio=3.611, 95%CI, 0.56 to 22.89); while the positive consanguinity strongly correlated with failure of the initial procedure (P=0.016, odds ratio=11.25, 95%CI, 1.57 to 80.30). However, the Kaplan-Meier survival analysis revealed a significantly lower time of IOP control in the subgroup with mutations in CYP1B1 versus the congenital primary glaucoma group without mutations (log rank test, P=0.015). CONCLUSION: Seven new CYP1B1 mutations are identified in Egyptian patients. Patients harboring confirmed mutations suffered from early failure of the initial surgery. CYP1B1 mutations could be considered as a prognostic factor for surgery in primary congenital glaucoma.