MYOC and FOXC1 gene analysis in primary congenital glaucoma.
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ABSTRACT:
SUBMITTER: Tanwar M
PROVIDER: S-EPMC2956699 | biostudies-literature | 2010
REPOSITORIES: biostudies-literature
Publications
MYOC and FOXC1 gene analysis in primary congenital glaucoma.
Tanwar Mukesh M Kumar Manoj M Dada Tanuj T Sihota Ramanjit R Dada Rima R
Molecular vision 20101008
<h4>Purpose</h4>To screen the myocilin (MYOC) and forkhead box protein C1 (FOXC1) genes for sequence variations in primary congenital glaucoma (PCG).<h4>Methods</h4>Seventy five PCG patients were screened for MYOC variations and 54 cases (negative or heterozygous for cytochrome P4501B1 mutations) for FOXC1 mutations by polymerase chain reaction (PCR) and DNA sequencing.<h4>Results</h4>Five single nucleotide polymorphisms (SNPs; -126T>C, -83G>A, p.R76K, IVS2+35G>A, and p.Y347Y) were identified in ...[more]
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Project description:PurposeTo screen primary congenital glaucoma patients in the United States for sequence variants within the CYP1B1, LTBP2, and MYOC genes using Sanger and whole exome sequencing.DesignRetrospective case-control study.MethodsFifty-seven primary congenital glaucoma patients (47 families), 71 unaffected family members of the primary congenital glaucoma probands, and 101 healthy unrelated individuals were recruited from a single institution. Sanger sequencing of the primary congenital glaucoma gene, CYP1B1, was performed on 47 proband deoxyribonucleic acid samples. Simultaneously, whole exome sequencing was conducted on 3 families, each including more than 1 affected individual. Concurrently, 33 of 47 primary congenital glaucoma probands with extended family deoxyribonucleic acid samples were screened for LTBP2 and MYOC gene mutations. Exome-sequenced variations were validated by additional Sanger sequencing to confirm segregation of filtered disease-causing single nucleotide variations.ResultsSeven primary congenital glaucoma families (14.9%) manifested disease phenotypes attributable to CYP1B1 mutations. One primary congenital glaucoma family possessed homozygous mutant alleles, whereas 6 families carried compound heterozygous mutations. Five novel combinations of compound heterozygous mutations were identified, of which 2 combinations were found with whole exome sequencing. No disease-causing mutations within the LTBP2 and MYOC genes were discovered.ConclusionsThis study analyzed CYP1B1, LTBP2, and MYOC mutations in a cohort of primary congenital glaucoma patients from the United States, applying whole exome sequencing as a complementary tool to Sanger sequencing. Whole exome sequencing, coupled with Sanger sequencing, may identify novel genes in primary congenital glaucoma patients who have no mutations in known primary congenital glaucoma genes.
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Project description:PurposeTo elucidate the incidence of cytochrome P450 1B1 (CYP1B1) and myocillin (MYOC) mutations in Korean patients with primary congenital glaucoma (PCG).MethodsGenomic DNA was collected from peripheral blood of 85 unrelated Korean patients who were diagnosed as having PCG by standard ophthalmological examinations and screened for mutations in the CYP1B1 and MYOC genes by using bi-directional sequencing.ResultsAmong 85 patients with PCG, 22 patients (22/85; 25.9%) had either one (n=11) or two (n=11) mutant alleles of the CYP1B1 gene. Among 11 different CYP1B1 mutations identified, a frameshift mutation (c.970_971dupAT; p.T325SfsX104) was the most frequent mutant allele (6/33; 18.2%) while p.G329S and p.V419Gfs11X were novel. In the MYOC gene, two variants of unknown significance (p.L228S and p.E240G) were identified in two PCG patients (2/85; 2.4%), respectively. No patient had mutations in both genes.ConclusionsAlthough CYP1B1 mutations are major causes of PCG in Korea, ~70% of PCG patients have neither CYP1B1 nor MYOC mutations suggesting a high degree of genetic heterogeneity. Furthermore, the fact that 11 out of 22 patients had only one mutant allele in the CYP1B1 gene necessitates further investigation for other genetic backgrounds underlying PCG.
| S-EPMC3156779 | biostudies-literature
Project description:ImportanceBoth primary and secondary forms of childhood glaucoma have many distinct causative mechanisms, and in many cases a cause is not immediately clear. The broad phenotypic spectrum of secondary glaucoma, particularly in individuals with variants in FOXC1 or PITX2 genes associated with Axenfeld-Rieger syndrome, makes it more difficult to diagnose patients with milder phenotypes. These cases are occasionally classified and managed as primary congenital glaucoma.ObjectiveTo investigate the prevalence of FOXC1 variants in participants with a suspected diagnosis of primary congenital glaucoma.Design, setting, and participantsAustralian and Italian cohorts were recruited from January 1, 2007, through March 1, 2016. Australian individuals were recruited through the Australian and New Zealand Registry of Advanced Glaucoma and Italian individuals through the Genetic and Ophthalmology Unit of l'Azienda Socio-Sanitaria Territoriale Grande Ospedale Metropolitano Niguarda in Milan, Italy. We performed exome sequencing, in combination with Sanger sequencing and multiplex ligation-dependent probe amplification, to detect variants of FOXC1 in individuals with a suspected diagnosis of primary congenital glaucoma established by their treating specialist. Data analysis was completed from June 2015 to November 2017.Main outcome and measuresIdentification of single-nucleotide and copy number variants in FOXC1, along with phenotypic characterization of the individuals who carried them.ResultsA total of 131 individuals with a suspected diagnosis of primary congenital glaucoma were included. The mean (SD) age at recruitment in the Australian cohort was 24.3 (18.1) years; 37 of 84 Australian participants (44.0%) were female, and 71 of 84 (84.5%) were of European ancestry. The mean (SD) age at recruitment was 22.5 (18.4) years in the Italian cohort; 21 of 47 Italian participants (44.7%) were female, and 45 of 47 (95.7%) were of European ancestry. We observed rare, predicted deleterious FOXC1 variants in 8 of 131 participants (6.1%), or 8 of 166 participants (4.8%) when including those explained by variants in CYP1B1. On reexamination or reinvestigation, all of these individuals had at least 1 detectable ocular and/or systemic feature associated with Axenfeld-Rieger syndrome.Conclusions and relevanceThese data highlight the genetic and phenotypic heterogeneity of childhood glaucoma and support the use of gene panels incorporating FOXC1 as a diagnostic aid, especially because clinical features of Axenfeld-Rieger syndrome can be subtle. Further replication of these results will be needed to support the future use of such panels.
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Project description:Glaucoma is known to induce visual impairment and blindness. The aim of the present study was to determine the clinical and genetic findings of a family with primary open-angle glaucoma (POAG). A family diagnosed with glaucoma was examined clinically and followed up for five years. Genomic DNA was extracted from the venous blood of 12 family members, and of 100 healthy individuals. The mode of inheritance was determined by the pedigree analysis. The third exon and its flanking introns of myocilin (MYOC) were amplified, and quantitative polymerase chain reaction (qPCR) products were sequenced. The restriction fragment length polymorphism analysis was performed on samples from the 12 family members and 100 normal controls. The predicted effects of the detected variants on the secondary structure of the MYOC protein were analyzed by the Garnier-Osguthorpe-Robson method. In this family, three members were diagnosed with POAG, and one member with ocular hypertension. The mode of inheritance of the family was autosomal dominant with six members being genetically affected. The heterozygous mutation was identified in the third exon of MYOC that revealed a T → C transition at position 1021 (p.S341P), which switched serine (Ser) to proline (Pro). This is a missense mutation eliminating a CviKI-1 restriction site that segregated the affected members. Secondary structure prediction of p.S341P suggested that the MYOC protein was misfolded. Ser341Pro MYOC mutation was detected in the family with POAG. The clinical and genetic characteristics of this mutation require further investigation. The mutation spectrum of MYOC may be expanded for a better diagnosis and treatment for POAG patients.
| S-EPMC4380197 | biostudies-literature
Project description:PurposeTo investigate the contribution of cytochrome P4501B1 (CYP1B1) and myocillin (MYOC) mutations to primary congenital glaucoma (PCG) in Moroccan families.MethodsThis study included 90 unrelated families with PCG and 100 normal control individuals. Two previously reported CYP1B1 mutations (g.4339delG and p.G61E) were first screened by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The coding exons of CYP1B1 were sequenced in g.4339delG- and p.G61E-negative or heterozygous probands. Then the coding exons of MYOC were sequenced in patients who had no mutation in CYP1B1 or carried heterozygous CYP1B1 mutation.ResultsTwelve CYP1B1 mutations were identified in 43 PCG pedigrees. Three of them were novel (p.R163C, p.C470Y, and g.4330-4331delTG) and associated with moderate to severe phenotypes. Two novel intronic polymorphisms in CYP1B1 were identified in addition to those previously described. The g.4339delG was the most frequent mutation detected in 31 families (34.44%), followed by the p.G61E in seven families (7.77%). The remaining mutations (p.R163C, p.E173K, g.4330-4331delTG, p.E229K, p.R390S, p.R368H, p.R469W, p.C470Y, and g.7901-7913del13bp) were infrequent. One family with the p.R390S mutation showed both PCG and primary open angle glaucoma (POAG) phenotypes. One proband was heterozygous for p.T193K mutation in MYOC. This mutation has been initially associated with POAG, but never with PCG.ConclusionsOur results support that mutations in CYP1B1 are a major cause for PCG in the Moroccan population with a predominance of the g.4339delG mutation. Furthermore, these results demonstrate the diversity of CYP1B1 mutations, while suggesting a modest role of MYOC in Moroccan PCG.
| S-EPMC2901188 | biostudies-literature
Project description:Primary congenital glaucoma (PCG) is the most common type of infantile glaucoma, yet it remains a relatively rare disease, because the disease is often transmitted in an autosomal recessive pattern. However, PCG occurs up to 10 times more frequently in certain ethnic and geographical groups where consanguineous relationships are common. The aim of this study was to investigate the distribution of mutations in the cytochrome P450 1B1 gene ( CYP1B1 ) in patients with PCG among different populations around the world from 2011 until May 2016. We referred to the electronic databases, such as Medline, Clinicalkey, Scopus, and ScienceDirect, to search for articles that were published in this area. Nineteen records were included in this qualitative synthesis. CYP1B1 mutations were assessed in 1,220 patients with PCG and identified in 41.6% of them. According to these studies, 99 mutations including 60 novel mutations were found. Nonsignificant difference in the sex ratio has been reported. This current review shows that consanguinity plays an important role in the PCG pathogenesis and transmission; however, sporadic mutations have been found in some cases. A difference in penetrance was highlighted by some mutations. The CYP1B1 mutations were mostly found in the Middle East and the Maghreb with a rate of 64.8 and 54.4%, respectively, followed by Europe (34.7%), Asia (21.3%), and finally the United States (14.9%). Founder mutations in different geographical areas have been discovered. For instance, the p.Gly61Glu, p.Arg390His, p.Gly61Glu, c.4,339delG, p.E387Lys, and p.Val320Leu were considered founder mutations for Iran/Saudi Arabia, Pakistan, Lebanon, Morocco, Europe, and Vietnam/South Korea, respectively. Many common mutations in different countries were found, such as in Morocco, where its mutations were similar to seven other countries. These findings suggest that the ethnic differences and the geographical distribution of PCG give us a large CYP1B1 mutation pattern. Genetic tests looking for founder and common mutations should be the first step in genetic screening for patients with PCG.
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Project description:The aim of this study is to examine whether or not myocilin (MYOC) genetic variations are associated with susceptibility to primary angle-closure glaucoma (PACG) in the Han Chinese population.Four single-nucleotide polymorphisms (SNPs)-rs235913, rs183532, rs12076134, and rs235875-in the MYOC gene were genotyped in 212 adult patients with PACG and 255 age-, sex-, and ethnic-matched healthy controls by using a polymerase chain reaction-restriction fragment length polymorphism assay. Data were analyzed by chi-square analysis.The four SNPs in the MYOC gene were in the Hardy-Weinberg equilibrium in all the subjects. The frequencies of A allele rs183532 were significantly different between the PACG patients and the controls (0.238 vs. 0.169, p=0.008; OR=1.541; 95% CI: 1.117-2.127). The frequencies of the AA genotype and A allele of rs235913 were increased in PACG patients compared with controls, but the difference was not significant (p=0.037, p=0.017, respectively). A comparison of the distributions of the genotypes and alleles of rs12076134 and rs235875 showed no statistically significant differences between the PACG patients and the controls (p>0.05). Haplotype analysis indicated that the frequency of the AATG and AATA haplotypes was significantly higher for PACG patients than for control subjects (both p<0.001). However, the frequency of CGGA and CGTG haplotypes was lower for PACG patients than for control subjects (p<0.001).Our study suggests that rs183532 is associated with an increased risk of PACG in the Chinese Han population.
| S-EPMC4278174 | biostudies-literature
Project description:Primary congenital glaucoma (PCG) is the cause of a significant proportion of inherited visual loss in children, but the underlying mechanism is poorly understood. In this study, we assessed the relationship between PCG and FOXC1 variants by Sanger sequencing the proximal promoter and transcribed sequence of FOXC1 from a cohort of 133 PCG families with no known CYP1B1 or MYOC mutations. The pathogenicity of the identified variants was evaluated by functional analyses. Ten patients (7.5%) with no family history of glaucoma carried five different rare heterozygous FOXC1 variants with both increased (rs77888940:C>G, c.-429C>G, rs730882054:c.1134_144del(CGGCGGCGCGG), p.(G380Rfs*144) and rs35717904:A>T, c.*734A>T) and decreased (rs185790394: C>T, c.-244C>T and rs79691946:C>T, p.(P297S)) transactivation, ranging from 50 to 180% of the wild-type activity. The five variants did not show monogenic segregation, and four of them were absent in a control group (n=233). To the best of our knowledge, one of these variants (p.(G380Rfs*144)) has not previously been described. One of the FOXC1 variant carriers (p.(P297S)) also coinherited a functionally altered rare PITX2 heterozygous variant (rs6533526:C>T, c.*454C>T). Bioinformatics and functional analyses provided novel information on three of these variants. c.-429C>G potentially disrupts a consensus sequence for a terminal oligopyrimidine tract, whereas c.-244C>T may alter the RNA secondary structure in the 5'-untranslated region (UTR) that affects mRNA translation. In addition, p.(G380Rfs*144) led to increased protein stability. In summary, these data reveal the presence of translation regulatory sequences in the UTRs of FOXC1 and provide evidence for a possible role of rare FOXC1 variants as modifying factors of goniodysgenesis in PCG.
| S-EPMC4930079 | biostudies-literature
Project description:PurposeTo screen mitochondrial DNA (mtDNA) for nucleotide variations in primary congenital glaucoma (PCG).MethodsThe entire coding region of the mitochondrial genome was amplified by polymerase chain reaction from 35 PCG patients and 40 controls. The full mtDNA genome except the D-loop was sequenced. All sequences were analyzed against mitochondrial reference sequence NC_012920.ResultsMtDNA sequencing revealed a total of 132 and 58 nucleotide variations in PCG and controls, respectively. Of 132 nucleotide variations, 42 (31.81%) were non-synonymous and 82 (62.12%) were synonymous changes, and 8 were in RNA genes. The highest number of nucleotide variations were recorded in complex I followed by complex IV, then complex V. Eight patients (22.85%) had potentially pathogenic mtDNA nucleotide changes and twenty (57.14%) had mtDNA sequence changes associated with elevated reactive oxygen species (ROS) production. Mitochondria not only constitute the energy-generating system in the cell, but are also critically involved in calcium signaling and apoptosis. Mitochondrial function can be affected by mutations in mitochondrial and nuclear DNA, chemical insults to components of the electron transport chain, and a lack of substrates such as oxygen. Mitochondrial dysfunction results in an excessive generation of free radicals and reduced mitochondrial respiration. Developing trabecular meshwork (TM) is deficient in antioxidant enzymes, and thus is more susceptible to oxidative stress (OS) induced damage. Previous studies have documented certain mtDNA sequence variations associated with elevated ROS levels and OS. Three such changes (G10398A, A12308G, and G13708A) were present in our patients. Elevated ROS may cause OS. This OS may further damage mtDNA and may cause decreased mitochondrial respiration. This may lead to impaired growth, development and differentiation of TM and consequently trabecular-dysgenesis, which is a characteristic feature of PCG. OS affects both TM and retinal ganglion cells (RGCs) and may be involved in the neuronal death affecting the optic nerve in glaucoma. There are several studies which point to mitochondrial dysfunction in different types of glaucoma and critically participate in RGC death. Recent studies also implicate mitochondrial dysfunction-associated OS as a risk factor for glaucoma patients. It has been reported that elevated hydrostatic pressure causes breakdown of the mitochondrial network by mitochondrial fission and induce cristae depletion and cellular ATP reduction in differentiated RGC-5 cells in vitro as well as in vivo.ConclusionsA total of 44 novel mtDNA variations were identified in this study. Non-synonymous mtDNA variations may adversely affect respiratory chain, impair OXPHOS pathway result in low ATP production, high ROS production and impair growth, development and differentiation of TM lead to trabecular-dysgenesis and consequently RGC's death. Such cases with mtDNA variations and consequent OS may benefit by early diagnosis and prompt management by antioxidant therapy. This may delay OS induced injury to TM and RGCs and hence improve visual prognosis.
| S-EPMC2846849 | biostudies-literature
Project description:PurposeTo analyze two candidate genes, trabecular meshwork inducible glucocorticoid response (MYOC/TIGR) and human dioxin-inducible cytochrome P450 (CYP1B1), in a Chinese pedigree of primary open-angle glaucoma.MethodsIn a three-generation family containing 14 members, four of them were patients with primary open-angle glaucoma, one was a glaucoma suspect, and the rest were asymptomatic. All members of the family underwent complete ophthalmologic examinations. Exons of MYOC and CYP1B1 were amplified by polymerase chain reaction, sequenced, and compared with a reference database.ResultsElevated intraocular pressure and impaired visual field were found in all patients. One MYOC heterozygous mutation G367R, in exon 3 was identified in four patients and the suspect, but not in the rest of the family members. Meanwhile, four single nucleotide polymorphisms in MYOC and CYP1B1 genes were found.ConclusionsAlthough the G367R mutation of MYOC, which causes primary open-angle glaucoma in the form of autosomal dominant inheritance, has been reported in some other ethnicities, it was found in Chinese pedigree for the first time.
| S-EPMC3108900 | biostudies-literature