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。     

湖北地区汉族原发性先天性青光眼患儿CYP1B1基因突变分析

目的研究湖北地区汉族原发性先天性青光眼(primary congenital glaucoma,PCG)患儿CYP1B1基因的突变情况。方法用苯酚-氯仿法从38例原发性先天性青光眼患儿的全血细胞中提取基因组DNA。然后通过聚合酶链反应-单链构象多态性(single-strand conformation polymorphism,PCR-SSCP)银染色法检测CYP1B1基因第2、3外显子的突变情况。结果5例PCG患儿检出CYP1B1基因第3外显子异常DNA片段条带,经测序分析证实为7990C→T,未发现第2外显子存在基因突变。结论CYP1B1基因具有明显的遗传异质性。应用PCR-SSCP技术可初步筛查原发性先天性青光眼患儿CYP1B1基因突变。     

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.     

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。     

CYP1B1基因突变与原发性开角型青光眼发病关系的研究进展

原发性青光眼包括原发性开角型青光眼（POAG）、原发性闭角型青光眼（PACG）及原发性婴幼儿青光眼（PCG）.目前认为原发性青光眼的发病是遗传因素、环境因素、生活习惯等多种因素综合作用的结果,其中遗传因素,尤其是基因突变,在青光眼的发病过程中起着重要作用.自1997年发现CYP1B1基因为PCG的致病基因以来,关于CYP1B1基因突变与青光眼发病关系的研究成为青光眼遗传和基因研究的热点.随着研究的逐渐深入,许多学者认为CYP1B1基因也是POAG致病基因的候选基因.本研究对近十余年来对CYP1 B1基因的结构和功能以及CYP1B1基因突变与POAG发病及进展关系的研究进展进行总结.     

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。     

CYP1B1基因与眼部发育

细胞色素P4501B1(cytochrome P450,family 1,subfamily b,polypeptide 1,CYP1B1)是细胞色素氧化酶P450家族1亚家族B的惟一成员,编码该蛋白的基因是首个被鉴定出来的婴幼儿型青光眼致病基因,其突变导致了部分先天性青光眼的发病.本文对该基因的结构、表达产物、影响眼部发育的可能机制作一综述.     

东北地区原发性闭角型青光眼家系PITX2基因和FOXC1基因突变筛查

目的通过分子遗传学研究筛查原发性闭角型青光眼家系PITX2基因和FOXC1基因突变情况。设计实验研究。研究对象东北地区原发性闭角型青光眼4个家系13例患者和24例健康成员。方法应用聚合酶链反应(PCR)扩增PITX2基因和FOXC1基因所有编码外显子,直接测序法筛查致病突变。主要指标PITX2基因、FOXC1基因序列。结果所分析的4个家系13例患者基因组DNA中均未检测到PITX2基因、FOXC1基因突变。结论 PITX2基因和FOXC1基因不是中国东北地区该原发性闭角型青光眼家系的致病病因。     

原发性开角型青光眼的相关致病基因

原发性开角型青光眼是一种主要与病理性高眼压有关,威胁和损害视神经视觉功能的临床眼病.其发病机制至今尚未完全阐明.自人类基因组计划实施以来,许多学者对原发性开角型青光眼的致病基因进行了大量的深入研究.此文从分子结构,基因表达以及突变和突变在发病过程中可能所起的作用等方面,对原发性开角型青光眼的相关致病基因MYOC、OPIN、WDR36、CYP1B1进行综述.     

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.     

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.     

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.     

Molecular genetics of primary congenital glaucoma in Brazil

PURPOSE: To determine the distribution of CYP1B1 gene mutations in Brazilian patients with primary congenital glaucoma (PCG). METHODS: PCG diagnosis was established by presence of buphthalmos in at least one affected eye and associated high intraocular pressures before the age of 3 years. CYP1B1 mutation screening of 52 patients with PCG was performed by SSCP and direct sequencing of PCR fragments. RESULTS: Eleven mutations, four of which are novel, were observed in 26 (50%) individuals. A new frameshift mutation (4340delG) was observed in 20.2% of all individuals screened. These individuals had early-onset, bilateral glaucoma that necessitated multiple surgical interventions. CYP1B1 mutations were twice as frequent in affected individuals of European descent as in individuals of African descent. Analysis of six intragenic single nucleotide polymorphisms (SNPs) established 5'-C-C-G-G-T-A-3' as the most common haplotype among the affected Brazilian individuals. A nonsense mutation (W57X) previously reported in an individual with Peters anomaly (compound heterozygote) was also observed in two individuals with PCG but combined with different mutations. A newly developed SSCP assay enabled us to detect all DNA mutations and polymorphisms previously detected by direct sequencing. CONCLUSIONS: Our results indicate that CYP1B1 mutations may be responsible for half of cases of PCG in the Brazilian population. The SNP haplotype 5'-C-C-G-G-T-A-3' was associated with the majority of CYP1B1 mutations. This haplotype harbors the high-activity V432 allele, which is emerging as a putative susceptibility factor in several cancers.     

A clinical and molecular genetic study of Egyptian and Saudi Arabian patients with primary congenital glaucoma (PCG)

PURPOSE: To undertake mutation screening of cytochrome P4501B1 (CYP1B1, OMIM 601771) and myocilin (MYOC, OMIM 601652) genes in Egyptian and Saudi Arabian patients with primary congenital glaucoma (PCG). PATIENTS AND METHODS: A clinical and molecular genetic study was performed on 11 Egyptian and Saudi Arabian patients with PCG. Clinical diagnosis was confirmed by slit lamp biomicroscopy, gonioscopy, measurement of intraocular pressure, and corneal diameter. The coding regions of CYP1B1 and MYOC genes were amplified by polymerase chain reaction for all affected subjects. Direct sequence analysis was performed to search for sequence alterations. Haplotype analysis and genotype/phenotype correlation were carried out. RESULTS: Three CYP1B1 mutations were identified in 5 PCG patients (45.4%) of which 2 were novel (homozygous E173K and heterozygous N498D) and the third (G61E) had previously been reported. In addition 10 single nucleotide polymorphisms were identified in CYP1B1 and MYOC genes of which 2 were novel. However, no pathologic changes in either of the genes were detected in the remaining 6 patients. CONCLUSIONS: This is the first report of molecular genetic analysis of PCG in the Egyptian population in which 2 novel mutations have been identified. It is possible that these mutations are specific to this population and may lead to alterations in the protein structure encoded by the gene. Patients with no mutations in the screened genes may have mutations in genes yet to be identified.     

Phenotype of cytochrome P4501B1 gene (CYP1B1) mutations in Japanese patients with primary congenital glaucoma

AIM: To investigate the phenotypes associated with cytochrome P4501B1 gene (CYP1B1) mutations in Japanese patients with primary congenital glaucoma (PCG). METHODS: 66 Japanese patients with PCG were screened for sequence mutations in the CYP1B1 gene using single strand conformation polymorphism analysis followed by automated DNA sequencing. 11 cases had a CYP1B1 mutation in both alleles (the mutation group) and 21 cases did not have a CYP1B1 mutation (the "no mutation" group). The clinical features, such as age of onset, sex, intraocular pressure, and Descemet's membrane rupture, of the two groups were compared. RESULTS: The clinical symptoms and signs did not differ for the two groups. The mean age at onset was 1.7 months in the mutation group and 3.1 months in the no mutation group, and the male:female ratio was 6:5 in the mutation group and 19:2 in the no mutation group. Both of these differences were statistically significant. CONCLUSIONS: In clinically diagnosed cases of PCG, a subgroup shows a CYP1B1 gene mutation. Age at onset was earlier in PCG patients with CYP1B1 mutations than in patients without mutations. Women were more prevalent among patients with mutations than those without mutations.