Analysis of myocilin gene mutations in Japanese patients with normal tension glaucoma and primary open-angle glaucoma

The myocilin gene was identified as a gene (MYOC) that caused primary open-angle glaucoma (POAG). Although a normal tension glaucoma (NTG) patient with the myocilin gene mutation was previously reported, no study using large numbers of patients with NTG has been reported. Single-strand conformation polymorphism analysis and subsequent sequence analysis were performed for genotyping the myocilin gene in 114 unrelated Japanese patients with NTG. One hundred and nineteen patients with POAG and 100 control subjects without glaucoma were studied as reference subjects. Five amino acid sequence changes of the myocilin were identified: Arg46Stop (one NTG), Arg76Lys (four NTG, 10 POAG, seven control), Arg158Gln (one NTG, one POAG, one control) found in only Japanese, Asp208Glu (four NTG, three POAG, one control), Pro481Ser (one control). Pro481Ser was novel. Arg76Lys always occurred with 1-83 from G to A in the promoter as it was reported in Chinese. Although some Japanese patients with NTG had sequence changes of the myocilin gene, there were no apparent specific mutations in patients with NTG.     

原发性开角型青光眼患者Myocilin基因的单核苷酸多态性

目的　探讨 Myocilin(MYOC)基因的单核苷酸多态性 (single nucleotide polymorphisms,SNPs)及其与原发性开角型青光眼 (primary open- angle glaucoma,POAG)发病的关系。方法　应用高通量构象敏感性凝胶电泳和荧光标记自动测序法筛选和鉴定香港 15 7例 POAG散发患者和 15 5名对照 MYOC基因的 SNPs。结果　在 MYOC基因所有 3个外显子及邻近的非编码区共检出 17种 SNPs:1- 83G→ A、G12 R、P16 L、A17S、R4 6 X、R76 K、R91X、T12 3T、D2 0 8E、L 2 15 P、730 35 A→ G、A2 6 0 A、I2 88I、E30 0 K、T35 3I、Y4 71C和 15 15 73G→ C。其中 ,R91X、E30 0 K和 Y4 71C仅在 POAG患者中检测到。此外 ,15 15 73G→ C各基因型在 POAG患者与对照人群中的分布差异具有显著意义 ,POAG患者中 CG型频率为 0 .6 % ,低于对照组的 4 .5 % (P=0 .0 36 )。其余 16种 SNPs各基因型在两组人群中的分布差异均无显著意义。结论　 MYOC基因多态性可能与中国人 POAG发病有关 ,提示 MYOC基因是 POAG的相关基因。     

是否合并有糖尿病的开角型青光眼小梁切除术后脉络膜厚度的改变

目的：观察开角型青光眼(primary open angle glaucoma,POAG)与开角型青光眼合并糖尿病患者小梁切除术后脉络膜厚度的变化。方法：选择在我院眼科住院治疗的开角型青光眼患者120例(130只眼)为研究对象,根据是否合并有糖尿病分为青光眼组69例(76只眼)和合并糖尿病组51例(54只眼),应用光学相干断层扫描技术(optical coherence tomography,OCT)于小梁切除术前后对视网膜色素上皮层到内巩膜层的垂直距离(即脉络膜厚度)进行测量。通过软件计算自动获得脉络膜平均厚度,观察并与术前比较是否有改变。结果：术前,两组视力、眼压和脉络膜厚度均无统计学差异(P>0.05)。小梁切除术后2周,合并糖尿病组脉络膜厚度比青光眼组厚,两组比较,差异具有统计学意义(P<0.05);但两组视力与眼压均无统计学差异(P>0.05)。组内治疗前后情况,两组视力与脉络膜厚度无统计学差异(P>0.05),但眼压在术后明显降低,差异具有统计学意义(t=10.76,P=0.00)。结论：开角型青光眼是否合并有糖尿病于小梁切除术后对脉络膜厚度无影响。     

Association of the myocilin mt.1 promoter variant with the worsening of glaucomatous disease over time

A major variant of myocilin (MYOC) [TIGR/MYOC mt.1 (-1000 C/G)], present in the gene's promoter, is found to be associated with more rapid progression of the glaucoma disease state. Time-to-event analyses using the Cox proportional hazards model produced substantial statistical evidence that this TIGR/MYOC mt.1(+) variant accelerates worsening for both optic disc and visual field measures of disease progression. These analyses were based on evaluations of 147 patients with primary open-angle glaucoma (POAG) over 35 years of age with an average follow-up of approximately 15 years. Our analyses showed that there are independent effects of the variant on disease progression, taking into account other relevant disease-related baseline risk factors, including age, family history, initial drug treatment, initial surgical treatment, diabetes, gender, myopia, and initial disease severity. The finding that a TIGR/MYOC mt.1(+) determination provided a strong marker for glaucoma progression, above and beyond the other baseline risk factors, suggests a clinical utility in testing for this promoter genotype.     

Novel mutations in the MYOC/GLC1A gene in a large group of glaucoma patients

Mutations at the myocilin (MYOC) gene within the GLC1A locus have been revealed in 2-4% of patients suffering primary open angle glaucoma (POAG) worldwide. In our ongoing glaucoma study six hundred eighty two persons have been screened for MYOC mutations. The first group consisted of 453 patients from a long-term clinical study diagnosed either with juvenile OAG (JOAG), POAG, ocular hypertension (OHT) or normal tension glaucoma (NTG) plus 22 cases of secondary glaucoma. This group, and additional 83 healthy controls, is part of a long term study with repeated clinical examinations at the University of Erlangen-Nurnberg. An additional sample of 124 glaucoma patients or at risk persons referred from other sources were included in the mutation screening. Five novel mutations, namely Gly434Ser, Asn450Asp, Val251Ala, Ile345Met and Ser393Asn, could be identified as cause of preperimetric POAG, JOAG, normal tension POAG and POAG. Myocilin mutations were identified similar with previous reports with other ethnic populations at the rate of 11/341 (3.2%) probands.     

Ultrastructure of connective tissue of eye drainage system in ophthalmic hypertension associated with primary juvenile glaucoma

In primary juvenile glaucoma, the connective tissue of the juxtacanalicular zone and sclera undergo constant reorganization because of incessant synthesis and degradation of extracellular matrix components with pronounced fluctuations of electron density of collagen fibrils. Destructive changes in the perivascular nerve trunks were detected at all stages of the glaucoma process, including the initial stages: numerous large foci of cytoplasmic organelle destruction with the formation of autophagosomes and residual bodies predominated in the cytoplasm of myelinated axons of nerve cells. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 145, No. 3, pp. 348–351, March, 2008     

Prevalence of CYP1B1 mutations in Australian patients with primary congenital glaucoma

Analysis of CYP1B1 in primary congenital glaucoma (PCG) patients from various ethnic populations indicates that allelic heterogeneity is high, and some mutations are population specific. No study has previously reported the rate or spectrum of CYP1B1 mutations in Australian PCG patients. The aim of this study is to determine the frequency of CYP1B1 mutations in our predominately Caucasian, Australian cohort of PCG cases. Thirty-seven probands were recruited from South-Eastern Australia, along with 100 normal control subjects. Genomic DNA was extracted and the coding regions of CYP1B1 analysed by direct sequencing. Sequence analysis identified 10 different CYP1B1 disease-causing variants in eight probands (21.6%). Five subjects were compound heterozygotes, two subjects heterozygous and one homozygous for CYP1B1 mutations. Three missense mutations are novel (D192Y, G329D, and P400S). None of the novel mutations identified were found in normal controls. One normal control subject was heterozygous for the previously reported CYP1B1 R368H mutation. Six previously described probable polymorphisms were also identified. Mutations in CYP1B1 account for approximately one in five PCG cases from Australia. Our data also supported the high degree of allelic heterogeneity seen in similar studies from other ethnic populations, thereby underscoring the fact that other PCG-related genes remain to be identified.     

Glycosaminoglycans of the trabecular meshwork of the eye in primary juvenile glaucoma

Significant changes in the qualitative and quantitative composition of glycosaminoglycans (decreased content of sulfated glycosaminoglycans and increased content of collagen-bound proteoglycanes) in the trabecular meshwork of the eye in primary juvenile glaucoma indicate fibrosis of the juxtacanalicular tissue, which was detected in pathomorphological examination of the operation material. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 143, No. 3, pp. 354–357, March, 2007     

中国闭角型青光眼病一家系MYOC和CYP1B1基因两突变分析

目的 对一个中国闭角型青光眼病家系进行分子遗传学研究.方法 对家系进行连锁分析,通过测序和单链构象多态性方法鉴定致病基因突变.结果 在家系患者中均发现MYOC基因的一个无义突变(Arg46Stop)以及CYP1B1基因的一个氨基酸改变(Leu432Val).而在无亲缘关系的健康中国汉族人群中没有检测到同时存在上述突变.结论 在一个闭角型青光眼病家系内鉴定了MYOC基因突变以及CYP1B1基因多态.该研究结果提示闭角型青光眼病的发病机制可能是二者协同作用的结果,并支持开角和闭角型青光眼病可能存在相同的发病机理的假说.     

Use of macular thickness parameters for the diagnosis of primary open-angle glaucoma

Introduction

Retinal thickness in primary open-angle glaucoma patients was determined to establish its correlation with advancement of glaucoma neuropathy.

Material and methods

One hundred ninety-four patients (371 eyes, age 30–65 years) were divided in 3 groups including 50 patients with confirmed primary open-angle glaucoma, 67 primary open-angle glaucoma-suspected patients and 77 healthy persons (control group). The retinal foveola, foveal, peri-foveal and posterior pole average thickness values were determined with an RTA analyzer. For comparison, linear cup-to-disc diameter ratio (C/D), nerve fiber index (NFI) and mean defect of the retina sensitivity (MD) were also determined.

Results

Statistically highly significant differences in the retinal thickness and glaucoma parameters between the individual groups were observed. In the peri-foveal region, the retinal thickness in glaucoma patients was only 173.0 ±11.4 µm while in the healthy patients 201.1 ±13.1 µm. In the posterior pole region, the thickness values were only 168.1 ±11.3 µm and 195.7 ±12.3 µm, respectively. A moderate correlation between retinal thickness in peri-foveal and posterior pole regions and the C/D, NFI and MD parameters was also established (Pearson coefficients below –0.351 or above 0.284).

Conclusions

The retinal thickness in the peri-foveal and posterior pole regions depends on the degree of glaucoma advancement. This original observation may be a basis for acceptance of this method as a quite new tool in glaucoma diagnosis.     

Evaluation of oxidative stress markers in pathogenesis of primary open-angle glaucoma

Primary open-angle glaucoma (POAG) is the leading cause of blindness in the industrial countries. It is reported that oxidative stress might be an important risk factor in the pathogenesis of POAG. Forty subjects including 20 patients with open-angle glaucoma (9 men and 12 women, mean age 61.8 ± 12.1 yr) and 20 controls without glaucoma symptoms (9 men and 12 women, mean age 58.1 ± 17.7 yr) were enrolled in our study. The main aim of the work was to evaluate oxidative stress markers in the pathogenesis of open-angle glaucoma. In our work the activity of antioxidant enzymes: catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPX) as well as the total antioxidant status (TAS) was estimated. An alkaline comet assay was used to measure DNA damage of strand breaks (SB), oxidized purines as glicosylo-formamido-glicosylase (Fpg) sites, and oxidized pirmidines as endonuclease III (Nth) sites. We measured endogenous as well as exogenous DNA damage after 10 μM hydrogen peroxide treatment (H₂O₂). We did not observe any statistical changes of DNA strand break lesion in examined POAG patients according to healthy subjects (P > 0.05). However, either endogenous (P < 0.01) or exogenous (P < 0.001) levels of oxidative DNA damage in POAG patients were found to be statistically higher than controls. A significant decrease of antioxidant enzymes: CAT (P < 0.001), SOD (P < 0.05), and GPX (P < 0.001) and a non-statistical decrease of TAS status (P > 0.05) in glaucoma patients according to controls were also indicated. In conclusion our data revealed that oxidative stress had a pathogenic role in primary open-angle glaucoma. Therefore, we suggested that the modulation of a pro-oxidant/antioxidant status might be a relevant target for glaucoma prevention and therapy.     

Genetic analysis of primary microcephaly in Indian families: novel ASPM mutations

Patients with primary microcephaly, an autosomal recessive trait, have mild to severe mental retardation without any other neurological deficits. It is a genetically heterogeneous disorder with six known loci: MCPH1 to MCPH6. Only the genes for MCPH1 and MCPH5 have been identified so far. We have ascertained nine consanguineous families with primary microcephaly from India. To establish linkage of these nine families to known MCPH loci, microsatellite markers were selected from the candidate regions of each of the six known MCPH loci and used to genotype the families. The results were suggestive of linkage of three families to the MCPH5 locus and one family to the MCPH2 locus. The remaining five families were not linked to any of the known loci. DNA-sequence analysis identified one known (Arg117X) and two novel (Trp1326X and Gln3060X) mutations in the three MCPH5-linked families in a homozygous state. Three novel normal population variants (i.e., c.7605G > A, c.4449G > A, and c.5961 A > G) were also detected in the ASPM gene.     

Risk factors for primary congenital glaucoma in the National Birth Defects Prevention Study

Primary congenital glaucoma (PCG) is a rare but serious birth defect. Genetic mutations have been implicated in the development of PCG, but little is known about nongenetic risk factors. This study investigates potential risk factors for PCG in the National Birth Defects Prevention Study (NBDPS), a large population‐based case–control study of major birth defects in the United States. The analysis includes case infants with PCG (N = 107) and control infants without birth defects (N = 10,084) enrolled in NBDPS from birth years 2000–2011. Pregnancy/infant clinical characteristics, demographics, and parental health history were collected through maternal interview. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were computed to examine associations with all PCG cases and isolated PCG cases without other major malformations. Associations with all the cases included term low birth weight (<2,500 g; aOR = 2.80, CI 1.59–4.94), non‐Hispanic black maternal race/ethnicity (aOR = 2.42, CI 1.42–4.13), maternal history of seizure (aOR = 2.73, CI 1.25–5.97), maternal antihypertensive use (aOR = 3.60, CI 1.52–8.53), and maternal sexually transmitted infection (aOR = 2.75, CI 1.17–6.44). These factors were also associated with isolated PCG, as was maternal use of nonsteroidal anti‐inflammatory drugs (aOR = 2.70, CI 1.15–6.34). This study is among the first to examine a wide array of potential risk factors for PCG in a population‐based sample.     

Absence/rarity of commonly reported LRRK2 mutations in Indian Parkinson's disease patients

Recent discovery of pathogenic mutations in the leucine-rich repeat kinase 2 (LRRK2) gene in Parkinson's disease (PD) patients in different ethnic groups have raised a hope of diagnostic screening and genetic counseling. We investigated the six most commonly reported mutations in LRRK2 gene among Indian PD patients, using PCR-RFLP method. Mutations G2019S, R1441C, R1441G, and R1441H were screened in 1012 individuals (PD, 800; controls, 212) while mutations I2012T and I2020T were screened in 748 PD patients. We did not observe any of these six mutations in this study sample except in a single female young onset PD patient who showed a heterozygous G2019S mutation. The absence of mutations was reconfirmed by sequencing of probands from several autosomal dominant PD families. Our observations suggest that these mutations may be a rare cause of PD among Indians and therefore of little help for diagnostic screening and genetic counseling for Indian PD patients.     

Stress reactivity of intraocular pressure after relaxation training in open-angle glaucoma patients

The present study was based on the hypothesis that stress may contribute to increased intraocular pressure (IOP) in open-angle glaucoma patients. It is investigated whether IOP reactivity to a mental stressor test (MST) can be influenced by relaxation training. Twenty three patients with open-angle glaucoma were randomly assigned either to a training group (TG) or to a waiting-list control group (CG). Prior to as well as after the completion of the training all patients were exposed to the MST. IOP and heart rate as well as self-ratings of psychological strain were assessed three times: (1) at baseline, (2) after exposition to the stressor, and (3) after a 10-min relaxation phase. Results provide evidence that the MST is a valid procedure to induce psychophysiological activation and that elevated IOP levels in open-angle glaucoma patients might be provoked by stressing situations. However, participation in the relaxation training did not influence IOP stress reactivity.     

Association of a single nucleotide polymorphism in the TIGR/MYOCILIN gene promoter with the severity of primary open-angle glaucoma

Primary open-angle glaucoma (POAG) is a highly prevalent optic neuropathy and a major cause of irreversible blindness, with elevation of intraocular pressure (IOP) being a primary risk factor. The trabecular meshwork-inducible glucocorticoid response (TIGR)/MYOCILIN (MYOC) gene coding region is mutated in 3-4% of POAG patients. Here, in a retrospective study of 142 POAG patients, we evaluated the influence on glaucoma phenotype of a novel biallelic polymorphism (-1000C/G) located in the upstream region of the MYOC gene. Allele frequencies were similar among patients and controls. However, the G allele (frequency 17.6%), also designated as MYOC.mt1, was associated with an increased IOP (+4.9 mmHg, p=0.0004) and a more damaged visual field (p=0.02). Both effects were predominant in females. Moreover, whereas IOP in MYOC.mt1 noncarriers decreased very markedly to the normal range between diagnosis and inclusion in the study (p=3 x 10(-5) in both males and females), reflecting successful therapy, it decreased less noticeably in MYOC.mt1+ male patients (p=0.005) and not at all in MYOC.mt1+ female patients. MYOC.mt1 appears therefore to be an indicator of poor IOP control and greater visual field damage in diagnosed POAG patients, potentially due to a lack of response to therapeutic intervention. Its typing might help in the selection of treatment paradigms for the management of POAG patients.     

BDNF and HSP gene polymorphisms and their influence on the progression of primary open-angle glaucoma in a Polish population

Introduction

Glaucoma is a neurodegenerative disease that is often associated with high intraocular pressure (IOP). One of the effects of elevated IOP is disorder of neurotrophic molecules transport, including brain-derived neurotrophic factor (BDNF) and recruit specific cellular proteins called “heat shock proteins” (HSPs). The aim of this study was to evaluate a relationship between the BDNF and HSP70-1 gene polymorphisms with risk occurrence of primary open-angle glaucoma (POAG).

Material and methods

The study consisted of 167 patients with POAG (mean age: 73 ±9) and 193 healthy subjects (mean age: 64 ±13). Genomic DNA was extracted from peripheral blood. Analysis of the gene polymorphisms was performed using PCR-RFLP, using the following restriction enzymes: NlaIII (rs6265) and BsrBI (rs1043618). The Heidelberg retinal tomography (HRT) clinical parameters were also analyzed. The odds ratios (ORs) and 95% confidence intervals (CIs) for each genotype and allele were calculated.

Results

Comparison of the distributions of genotypes and alleles of the 196G/A polymorphism of the BDNF gene as well as 190G/C polymorphism of the HSP70-1 gene and analysis of the odds ratio (OR) showed no statistically significant differences between POAG patients and controls (p > 0.05). However, there was a statistically significant association of the 196G/A of BDNF and 190G/C of HSP70-1 gene polymorphisms with progression of POAG depending on values of clinical parameters. 196G/A of BDNF correlated with the parameters GDx and RA (p = 0.03; p = 0.002, respectively), while 190G/C of HSP70-1 correlated with c/d and RA (p = 0.014, p = 0.024, respectively).

Conclusions

The BDNF 196G/A and HSP70-1 190G/C gene polymorphisms may be related to progression of POAG.     

Low frequency of common LRRK2 mutations in Mexican patients with Parkinson's disease

Mutations in leucine-rich repeat kinase 2 gene (LRRK2) account for as much as 5–6% of familial Parkinson's disease (PD) and 1–2% of sporadic PD. These mutations represent the most frequent cause of autosomal dominant PD, particularly in certain ethnic groups. In this first report concerning LRRK2 mutations in Mexican-mestizos, we screened 319 consecutive PD patients (186 males; 133 females; mean age at onset: 52.4 years) for LRRK2 mutations in exons 31 and 41 and for the mutation in exon 35, which produces the Y1699C substitution. Three (0.94%) patients, two with sporadic PD and one with familial PD (disease mean age at onset, 53.3 years), were heterozygous for LRRK2 mutations. Of these three, two patients had one of two different mutations in exon 31 (R1441G and R1441H, respectively); the other patient carried the G2019S mutation in exon 41. The Y1699C mutation was absent from this PD sample. Four additional subjects, unaffected relatives of one PD patient with a mutation in LRRK2, were subsequently genetically tested. None of the three LRRK2 mutations identified was present in 200 neurologically healthy Mexican control individuals. These findings have important implications for molecular testing of LRRK2 mutations in Mexican PD patients.     

Low frequency of AXIN2 mutations and high frequency of MUTYH mutations in patients with multiple polyposis

Familial adenomatous polyposis has been linked to germline mutations in the APC tumor suppressor gene. However, a number of patients with familial adenomatous polyposis (with either classical or attenuated phenotype) have no APC mutation. Recently, germline mutations in the Wnt pathway component gene AXIN2 have been associated with tooth agenesis-colorectal cancer syndrome. Moreover, biallelic mutations in the base excision repair gene MUTYH have been associated with polyposis and early-onset colorectal cancer. The aim of this study was to further assess the contribution of AXIN2 and MUTYH to hereditary colorectal cancer susceptibility. AXIN2 and MUTYH genes were screened for germline mutations by PCR and direct sequencing in 39 unrelated patients with multiple adenomas or colorectal cancer without evidence of APC mutation nor mismatch repair defect. Two novel AXIN2 variants were detected in one patient with multiple adenomas, but no clearly pathogenic mutation. In contrast, nine different MUTYH mutations were detected in eight patients, including four novel mutations. Biallelic MUTYH mutations were only found in patients with multiple adenomatous polyposis (7 out of 22 (32%)). Interestingly, five MUTYH mutation carriers had a family history consistent with dominant inheritance. Moreover, one patient with biallelic MUTYH mutations presented with multiple adenomas and severe tooth agenesis. Therefore, germline mutations are rare in AXIN2 but frequent in MUTYH in patients with multiple adenomas. Our data suggest that genetic testing of MUTYH may be of interest in patients with pedigrees apparently compatible with autosomal recessive as well as dominant inheritance.