The Genetic and Endoplasmic Reticulum-Mediated Molecular Mechanisms of Primary Open-Angle Glaucoma.

Glaucoma is a heterogenous, chronic, progressive group of eye diseases, which results in irreversible loss of vision. There are several types of glaucoma, whereas the primary open-angle glaucoma (POAG) constitutes the most common type of glaucoma, accounting for three-quarters of all glaucoma cases. The pathological mechanisms leading to POAG pathogenesis are multifactorial and still poorly understood, but it is commonly known that significantly elevated intraocular pressure (IOP) plays a crucial role in POAG pathogenesis. Besides, genetic predisposition and aggregation of abrogated proteins within the endoplasmic reticulum (ER) lumen and subsequent activation of the protein kinase RNA-like endoplasmic reticulum kinase (PERK)-dependent unfolded protein response (UPR) signaling pathway may also constitute important factors for POAG pathogenesis at the molecular level. Glaucoma is commonly known as a 'silent thief of sight', as it remains asymptomatic until later stages, and thus its diagnosis is frequently delayed. Thereby, detailed knowledge about the glaucoma pathophysiology is necessary to develop both biochemical and genetic tests to improve its early diagnosis as well as develop a novel, ground-breaking treatment strategy, as currently used medical therapies against glaucoma are limited and may evoke numerous adverse side-effects in patients.

MicroRNAs in glaucoma and neurodegenerative diseases.

MicroRNAs (miRNAs) constitute a class of short, non-coding RNAs, which have important role in post-transcriptional regulation of genes expression by base-pairing with their target messenger RNA (mRNA). In recent years, miRNAs biogenesis, gene silencing mechanism and implication in various diseases have been thoroughly investigated. Many scientific findings indicate the altered expression of specific miRNA in the brains of patients affected by neurodegenerative diseases (NDs) such as Alzheimer's disease, Parkinson's disease and Huntington disease. The progressive optic nerve neuropathy associated with changed miRNA profile was also observed during glaucoma development. This suggests that the miRNAs may have a crucial role in these disorders, contributing to the neuronal cell death. A better understanding of molecular mechanism of these disorders will open a new potential way of ND treatment. In this review, the miRNAs role in particular neurodegenerative disorders and their possible application in medicine was discussed.

Next-generation sequencing of ABCA4: High frequency of complex alleles and novel mutations in patients with retinal dystrophies from Central Europe.

Variation in the ABCA4 locus has emerged as the most prevalent cause of monogenic retinal diseases. The study aimed to discover causative ABCA4 mutations in a large but not previously investigated cohort with ABCA4-related diseases originating from Central Europe and to refine the genetic relevance of all identified variants based on population evidence. Comprehensive clinical studies were performed to identify patients with Stargardt disease (STGD, n = 76) and cone-rod dystrophy (CRD, n = 16). Next-generation sequencing targeting ABCA4 was applied for a widespread screening of the gene. The results were analyzed in the context of exome data from a corresponding population (n = 594) and other large genomic databases. Our data disprove the pathogenic status of p.V552I and provide more evidence against a causal role of four further ABCA4 variants as drivers of the phenotype under a recessive paradigm. The study identifies 12 novel potentially pathogenic mutations (four of them recurrent) and a novel complex allele p.[(R152*; V2050L)]. In one third (31/92) of our cohort we detected the p.[(L541P; A1038V)] complex allele, which represents an unusually high level of genetic homogeneity for ABCA4-related diseases. Causative ABCA4 mutations account for 79% of STGD and 31% of CRD cases. A combination of p.[(L541P; A1038V)] and/or a truncating ABCA4 mutation always resulted in an early disease onset. Identification of ABCA4 retinopathies provides a specific molecular diagnosis and justifies a prompt introduction of simple precautions that may slow disease progression. The comprehensive, population-specific study expands our knowledge on the genetic landscape of retinal diseases.

Systemic immunosuppression with mycophenolate mofetil to prevent corneal graft rejection after high-risk penetrating keratoplasty: a 2-year follow-up study.

PURPOSE: In this study, we aimed to evaluate the efficacy and safety of systemic immunosuppression with mycophenolate mofetil (MMF) to prevent corneal graft rejection after high-risk penetrating keratoplasty. METHODS: One hundred and ninety-six consecutive patients who underwent high-risk penetrating keratoplasty defined as the presence of deep vascularization in more than two quadrants, keratouveitis, emergency keratoplasties, and retransplantations were enrolled in the study. Ninety-eight prospectively followed up patients were treated with MMF [with dose adjustment based on mycophenolic acid (MPA) serum concentration], and 98 patients were in the non-MMF-treated retrospectively assessed control group. RESULTS: During a mean of 24 months of observation, immune reactions occurred in eight cases (8 %) and graft rejection with subsequent graft failure occurred in three cases (3 %) in the MMF group. In the control group, graft rejection occurred in 76 cases (78 %) and failure due to graft rejection occurred in 30 cases (31 %). Kaplan-Meier analysis demonstrated that 93 % of the grafts in the MMF-treated group and 47 % in the control group showed no immune rejection (p < 0.01, log-rank test) after a year. Cox regression analysis proved that MMF treatment decreased the risk of graft rejection 11 times (RR = 11, 95.0 % CI 4.8-25, p < 0.0001). Among 98 MMF-treated patients, 13 had gastric discomfort, three developed leucopenia, and two had anemia that resolved after MMF dose reduction. CONCLUSIONS: MMF treatment after high risk penetrating keratoplasty is safe and reduces the incidence of immune graft rejection and graft failure. Side effects were rare and reversible in all but one case.

The role of Cat -262C/T, GPX1 Pro198Leu and Sod1+35A/C gene polymorphisms in a development of primary open-angle glaucoma in a Polish population.

The development of glaucoma may be connected with a long-term exposure to oxidative stress caused by free radical (ROS). The main aim of this work was an analysis of associations of Cat-262C/T, GPX1 Pro198Leu and SOD1 35 A/C gene polymorphisms of antioxidant enzymes with a risk of open-angle glaucoma (POAG) in a Polish population. DNA samples collected from 209 patients with POAG and 191 healthy controls were used in this study. Polymorphisms were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). We found that the +35A/C polymorphisms of SOD1 were not associated with a risk of POAG. We found that C/T genotype (1-GPX1Pro198Leu, 2-Cat C262T) is associated with increased risk of open angle glaucoma (1-OR = 2.24; 95% CI: 1.46-3.44; p = 0.0001, 2-OR = 2.16; 95% CI: 1.35-3.34; p = 0.001). We also found that T/T genotype is a risk factor for progression of POAG (1-OR = 3.86; 95% Cl: 1.36-10.96; p = 0.007, 2-OR = 6.37; 95% CI: 1.39-29.28; p = 0.007). Finally our data suggest that gene polymorphisms of GPX1 Pro198Leu and CAT C262T may have a protective role in the development of primary open-angle glaucoma in a Polish population.

Immunomodulation on the ocular surface: a review.

The increasing understanding of immune mechanisms changed our perception of the ocular surface, which is now considered a compartment of the common mucosal immune system. It offered the possibility to alter the physiological immune response on the ocular surface and effectively combat inflammation, which impairs stability of the tear film and causes tear hyperosmolarity, causing symptoms of dry eye disease. The paper provides an overview of ocular surface anatomy and physiology, explains the underlying mechanisms of dry eye disease and discusses novel and promising treatment modalities, such as cyclosporine A, biological therapies using autologous serum and various growth factors as well as experimental treatment methods which are currently being investigated.

Effect of 0.1% diclofenac ophthalmic solution on inflammatory response and macular thickness following phacoemulsification cataract surgery. / [Wplyw 0,1% kropli diklofenaku na odczyn zapalny w komorze przedniej oka i stan plamki po operacji fakoemulsyfikacji zacmy].

Purpose: To evaluate 0.1% diclofenac sodium as an adjunctive therapy with loteprednol etabonate on postoperative inflammation in the anterior chamber and on foveal and parafoveal retinal thickness. Material and methods: Eighty eyes eligible for phacoemulsification were enrolled in a randomized clinical trial. Patients in group I (N = 40) received anti-inflammatory treatment consisting of 0.1% diclofenac with 0.5% loteprednol; group II (N = 40) patients received 0.5% loteprednol alone. Best corrected visual acuity and intraocular pressure were measured, and laser flarephotometry was done. Foveal and parafoveal thickness were assessed by optical coherence tomography. Results: Median flare values decreased more rapidly in group I at 7 and 14 days (7.9 and 7.4 ph/ms, respectively) than in group II (13.7 and 11.8 ph/ms, respectively; p < 0.0001). Group II had significantly increased parafoveal thickness at 14 and 42 days (median 285.59 µm, p = 0.001 and 288.38 µm, p < 0.001, respectively). Parafoveal thickness differed significantly between groups at 14 and 42 days (p = 0.0085, p = 0.0004, respectively). Conclusions: Eyes treated with both diclofenac sodium and loteprednol etabonate showed less inflammatory response and were less likely to develop foveal and parafoveal thickening than those treated with steroid only.

Evaluation pro/antioxidant balance in patients with wet form of age-related macular degeneration. / [Ocena równowagi proantyoksydacyjnej u chorych na wysiekowa postac zwyrodnienia plamki zwiazanego z wiekiem].

Objective: The aim of study was to evaluate the ability of the enzymatic antioxidant barrier to protect against peroxidation in patients with wet age-related macular degeneration, as compared to healthy subjects. Material and methods: Hemolysate blood samples collected from 25 patients with wet form age-related macular degeneration and 25 healthy controls were analysed to determine the activity of superoxide dismutase (using Misra and Fridovich method), catalase (using Beers and Sizer method), glutathione peroxidase (using Sedlak and Lindsay method modified by Little and O'Brien), and malondialdehyde concentration (using Placer method). Results: We observed a statistically significant decrease in the activity of following enzymes in patients with wet age-related macular degeneration, as compared to controls: superoxide dismutase (2086.3 vs. 2348.5 U/gHb/100 ml; p ≤ .05), catalase (6.9 vs. 7.6 BU/gHb, p ≤ .05) and glutathione peroxidase (36.3 vs. 45.8 U/gHb; p ≤ .05). At the same time, an increase in age-related macular degeneration thiobarbituric acid reactive substance concentration was demonstrated in patients with wet age-related macular degeneration, as compared to healthy subjects (.119 vs. .286 µmol/gHb; p ≤ .001). Conclusion: The obtained results indicate inefficient enzymatic antioxidant system which manifests as intense peroxidation in patients with age-related macular degeneration.

The analysis of single nucleotide polymorphisms of the DGCR8 and XPO5 genes, and their association with the incidence of primary open angle glaucoma. / Analiza polimorfizmów pojedynczych nukleotydów genów DGCR8 i XPO5 oraz ich zwiazek z wystepowaniem jaskry pierwotnej otwartego kata.

Purpose: To analyse the single nucleotide polymorphisms of DGCR8 and XPO5 genes, involved in miRNA processing pathway, in relation to the incidence of primary open-angle glaucoma. Material and methods: Blood samples as the biological material used for the experiment were voluntarily donated by patients with known primary open-angle glaucoma and age-matched healthy controls. The two control groups ­ rs3757 DGCR8 and rs11077 XPO5 ­ consisted of 135 and 140 volunteers, respectively. The two study groups ­ rs3757 DGCR8 and rs11077 XPO5 ­ consisted of 137 and 138 subjects, respectively. The polymorphic variant frequencies of rs3757 and rs1107 were determined using DNA isolated from the peripheral blood lymphocytes in TaqMan® SNP Genotyping Assays. Results: The statistical analysis revealed that the genotype AG of DGCR8 rs3757 occurred more frequently in healthy individuals (P = 0.001), while homozygote GG was present mostly in people affected by primary open-angle glaucoma (P = 0.003). No association between the risk of primary open angle glaucoma and AC/CC genotypes of XPO5 was found. Conclusions: Many reports suggest the association between the miRNA alteration and the pathogenesis of glaucoma. The single nucleotide polymorphisms in DGCR8 and XPO5 genes, involved in microRNA biogenesis, may be the key factor in this process. Our experiment showed that genotype AG in rs3757 DGCR8 exhibits protective effect, decreasing the risk of primary open angle glaucoma, while the homozygote GG is probably associated with increased risk of glaucoma. The analysis of polymorphic variants of the genes involved in miRNA biogenesis could enable identification of glaucoma high-risk groups.

The opinion of the Expert Group of the Polish Society of Ophthalmology on using nepafenac in the prevention of postoperative macular edema after cataract surgery in diabetic patients.

Nepafenac is an innovative non-steroidal anti-inflammatory drug used in ophthalmology for the prevention of macular edema after cataract surgery. Along with its anti-inflammatory effect, nepafenac has some unique properties which distinguish it from other non-steroidal anti-inflammatory drugs. It is a prodrug activated to amfenac after it penetrates through the corneal layers to the aqueous humour and the ciliary body. Having electrically neutral molecules of lipophilic properties, nepafenac does not accumulate in the cornea and does not cause its degeneration. Additionally, it quickly achieves higher concentrations in the aqueous humour as compared to other non-steroidal anti-inflammatory drugs. Nepafenac shows high selectivity and activity against COX-2 isoform, the key enzyme implicated in inducing inflammation, which is the main cause of macular edema. Furthermore, nepafenac has the unique scleral and suprachoroidal distribution pathways. Finally, its effect on the intraocular pressure is none to negligible. Nepafenac treatment should be initiated prior to cataract surgery and continued long enough to reduce the risk of late-onset macular edema. The Expert Group of the Polish Society of Ophthalmology consider using nepafenac in the prevention of post­operative macular edema in diabetic patients undergoing cataract surgery as expedient and reasonable. The proposed optimum pre- and postoperative treatment regimen can be modified for individualised therapy.

Electrophysiological testing as a method of cone-rod and cone dystrophy diagnoses and prediction of disease progression.

PURPOSE: To determine the characteristics of patients with cone (CD) and cone-rod dystrophies (CRD) and to evaluate the changes in flash electroretinograms in both groups. METHODS: The retrospective study involved 48 patients-34 with CRD and 14 with CD. The patients underwent full ophthalmological examination, including Goldmann perimetry and full-field flash electroretinogram (FERG) within the initial examination. These examinations were then repeated seven, or more, years later. The longest follow-up period was 10 years, with the mean at 8.2 years. During both examinations, we assessed the amplitudes of the b wave in the scotopic ERG test 0.01 (which reflects rod response), the maximal scotopic ERG test 3.0 (which reflects cone and rod response) and the photopic 3.0 ERG test (which reflects cone response). The results were then compared against normal values. RESULTS: The progression over time of ERG b wave amplitudes in the scotopic ERG 0.01, maximal scotopic ERG 3.0 and photopic ERG tests was assessed. There were significant differences in rod, maximal and cone responses, between CD and CRD patients. While rod responses were markedly decreased in CRD patients during their initial examination, the decrease in the rod function in both CD and CRD patients was similar in their follow-up examination (p = 0.2398). Moreover, during initial examination, maximal responses were less common amongst CRD patients, over those with CD. Following the observation period, patients suffering from CRD exhibited a significant decrease in both maximal (p = 0.0125) and cone (p = 0.0046) responses. CONCLUSION: The clinical course of CRD and CD may vary; however, the latter appears to have a more favourable course than former. Although, at initial examination, the cone function was more diminished in CD patients, the final examinations reveal a more significant drop for CRD patients. Consequently, a differential diagnosis is essential for treating patients and forecasting their disease progression.

Polymorphism of the APEX nuclease 1 gene in keratoconus and Fuchs endothelial corneal dystrophy.

Human APEX nuclease 1 (APEX1) plays an important role in the repair of oxidative DNA lesions through base excision repair. It may influence the development of oxidative stress-related diseases. The aim of this study was to determine the relationship between the genotypes of the c.444 T>G (rs1130409) and c.-468 T>G (rs1760944) polymorphisms in the APEX1 gene and the occurrence of two oxidative stress-related eye diseases: keratoconus (KC) and Fuchs endothelial corneal dystrophy (FECD). The study involved 250 patients with KC, 209 patients with FECD, and 350 control subjects. All of the patients and control subjects underwent a detailed ophthalmic examination. The polymorphisms were genotyped by mismatch polymerase chain reaction restriction fragment length polymorphism (mismatch PCR-RFLP). We observed that the G/T and T/T genotypes of the c.-468 T>G polymorphism were respectively associated with a decreased occurrence of KC (OR 0.54, 95% CI 0.37-0.95; p = 0.030) and an increased occurrence of KC (OR 1.87, 95% CI 1.06-3.32; p = 0.032). None of these polymorphisms showed any association with FECD. Furthermore, no other association was observed, including haplotypes of the two polymorphisms. Our findings suggest that the c.-468 T>G polymorphism of the APEX1 gene may play a role in the pathogenesis of KC.

Variation in DNA Base Excision Repair Genes in Fuchs Endothelial Corneal Dystrophy.

BACKGROUND Fuchs endothelial corneal dystrophy (FECD) is a corneal disease characterized by abnormalities in the Descemet membrane and the corneal endothelium. The etiology of this disease is poorly understood. An increased level of oxidative DNA damage reported in FECD corneas suggests a role of DNA base excision repair (BER) genes in its pathogenesis. In this work, we searched for the association between variation of the PARP-1, NEIL1, POLG, and XRCC1 genes and FECD occurrence. MATERIAL AND METHODS This study was conducted on 250 FECD patients and 353 controls using polymerase chain reaction-restriction fragment length polymorphism, high-resolution melting analysis, and the TaqMan® SNP Genotyping Assay. RESULTS We observed that the A/A genotype and the A allele of the c.1196A>G polymorphism of the XRCC1 gene were positively correlated with an increased FECD occurrence, whereas the G allele had the opposite effect. A weak association between the C/G genotype of the g.46438521G>C polymorphism of the NEIL1 gene and an increased incidence of FECD was also detected. Haplotypes of both polymorphisms of the XRCC1 were associated with FECD occurrence. No association of the c.2285T>C, c.-1370T>A and c.580C>T polymorphisms of the PARP-1, POLG and XRCC1 genes, respectively, with FECD occurrence was observed. CONCLUSIONS Our results suggest that the c.1196A>G polymorphism in the XRCC1 gene may be an independent genetic risk factor for FECD.

Association between polymorphism of the DNA repair SMUG1 and UNG genes and age-related macular degeneration.

PURPOSE: To investigate the association between the g.4235T>C (rs2337395) polymorphism of the UNG gene and the c.-31A>G (rs3087404) polymorphism of the SMUG1 gene and the risk of age-related macular degeneration (AMD), as well as modulation of this association by some environmental and lifestyle factors. METHODS: Overall, 272 AMD patients and 105 control subjects were enrolled in this study. Both polymorphisms were genotyped by restriction fragment length polymorphism-polymerase chain reaction (PCR-RFLP). RESULTS: The C/C genotype of the g.4235T>C polymorphism of the UNG gene was associated with an increased risk of dry AMD (odds ratio, 2.54), whereas the T/T genotype of this polymorphism decreased such risk (odds ratio, 0.41). The presence of the T allele of the g.4235T>C polymorphism and the A allele of the c.-31A>G polymorphism of the SMUG1 gene (odds ratio, 2.17 and 2.18, respectively) was associated with an increased risk of AMD severity, expressed by the comparison of the frequencies of genotypes in the group of patients with wet AMD versus those with dry AMD. Conversely, the C/C genotype of the g.4235T>C polymorphism, the G/G genotype of the c.-31A>G polymorphism, and the C/C-G/G combined genotype of both polymorphisms had a protective effect (odds ratio, 0.48, 0.46, and 0.18; respectively). CONCLUSION: The results obtained suggest the potential role of the g.4235T>C and the c.-31A>G polymorphisms in AMD pathogenesis.

Monitoring of in vitro dynamics of Acanthamoeba strains isolated from infected eyes as a useful tool in keratitis management.

Free-living amoebae of Acanthamoeba genus are ubiquitous in various parts of the world. Some species of these amoebozoans present a serious risk to human health as the causative agents of vision-threatening diseases, Acanthamoeba keratitis. Correct diagnosis requires both a clinical examination of the cornea and amoebic form identification in affected eyes. Despite advances in pharmacotherapy, the infection is difficult to diagnose and to threat. Population dynamics of five different Acanthamoeba strains cultured in vitro under bacteria-free condition in BSC medium, was monitored in terms of diagnostic and therapeutic management. The range of protozoan number in the exponential growth phase, the morpho-physiological status of amoeba forms and their ability to multiply were evaluated. Results of the studies revealed that early and continued monitoring of the strains maintained in an axenic culture showed correlation between the dynamics of cultivated amoebae and the course of the disease, differences in response to pharmacotherapy and the surgical management efficacy. Concluding, the in vitro monitoring of dynamics of Acanthamoeba strains isolated from infected corneas may be important not only for proper diagnosis but also as a useful tool in keratitis management and therapeutic prognosis.

In vitro effects of selected contact lens care solutions on Acanthamoeba castellanii strains in Poland.

Free-living, cosmopolitan amoebae of the Acanthamoeba genus may be the causative agents of Acanthamoeba keratitis (AK) - a progressive, vision-threatening infection of the human cornea described particularly among contact lens wearers. Use of contact lens care solutions, effective against these organisms, is important in preventing AK infections. 3 different strains of Acanthamoeba castellanii of the T4 genotype (Neff strain and two others, isolated from patients with AK) were exposed to 4 selected multipurpose contact lens care solutions available in Poland: Ciba Vision AoSept Plus, Bausch & Lomb ReNu MultiPlus, Alcon Opti-Free, Ciba Vision Solo Care Aqua. No amoebicidal effect was observed. The strongest amoebostatic effect was visible after 24h of exposition to Opti-Free and ReNu solution and associated with percentage increase of rounded, motionless forms. This is significantly longer than minimum disinfection time recommended by manufacturers of all tested multipurpose solutions. Surprisingly, no clear induction of the encystation process was observed.

Polymorphisms of the apoptosis-related FAS and FAS ligand genes in keratoconus and Fuchs endothelial corneal dystrophy.

Keratoconus (KC) is a non-inflammatory eye disease characterized by progressive corneal thinning and asymmetrical conical protrusion of the cornea. Fuchs endothelial corneal dystrophy (FECD) is a degenerative, slowly progressive disease of the corneal endothelium that is characterized by alteration in corneal endothelial cell morphology and progressive loss of these cells. They are unrelated eye diseases that may ultimately lead to vision loss. Their pathogenesis is largely unknown, although impaired apoptosis has been suggested to be responsible for both diseases. Therefore, we studied the frequency of the c.-671A>G polymorphism of the apoptosis-related FAS gene and the c.-844T>C polymorphism of the FAS ligand (FASLG) gene in patients with FECD (221 individuals) or KC (264) and controls (300). Each polymorphism is located within the putative cis-acting element of the respective promoter. Risk of KC or FECD was estimated with unconditional multiple logistic regression with adjustment for various factors, including age, sex, allergies, and family history. The T/T genotype and the T allele of the c.-844T>C polymorphism were associated with increased occurrence of KC, while the C allele was associated with decreased KC occurrence. The G allele of the c.-671A>G polymorphism was associated with increased occurrence of FECD, while the A allele was associated with decreased FECD occurrence. The C/C-A/A combined genotype was associated with reduced risk of FECD, whereas the T/T-G/A combined genotype increased risk of KC. In conclusion, variability in the expression of the FAS and FASLG genes may be involved in the pathogenesis of KC and FECD.

Polymorphism of the DNA base excision repair genes in keratoconus.

Keratoconus (KC) is a degenerative corneal disorder for which the exact pathogenesis is not yet known. Oxidative stress is reported to be associated with this disease. The stress may damage corneal biomolecules, including DNA, and such damage is primarily removed by base excision repair (BER). Variation in genes encoding BER components may influence the effectiveness of corneal cells to cope with oxidative stress. In the present work we genotyped 5 polymorphisms of 4 BER genes in 284 patients and 353 controls. The A/A genotype of the c.-1370T>A polymorphism of the DNA polymerase γ (POLG) gene was associated with increased occurrence of KC, while the A/T genotype was associated with decreased occurrence of KC. The A/G genotype and the A allele of the c.1196A>G polymorphism of the X-ray repair cross-complementing group 1 (XRCC1) were associated with increased, and the G/G genotype and the G allele, with decreased KC occurrence. Also, the C/T and T as well as C/C genotypes and alleles of the c.580C>T polymorphism of the same gene displayed relationship with KC occurrence. Neither the g.46438521G>C polymorphism of the Nei endonuclease VIII-like 1 (NEIL1) nor the c.2285T>C polymorphism of the poly(ADP-ribose) polymerase-1 (PARP-1) was associated with KC. In conclusion, the variability of the XRCC1 and POLG genes may play a role in KC pathogenesis and determine the risk of this disease.

Polymorphism of the flap endonuclease 1 gene in keratoconus and Fuchs endothelial corneal dystrophy.

Oxidative stress is implicated in the pathogenesis of many diseases, including serious ocular diseases, keratoconus (KC) and Fuchs endothelial corneal dystrophy (FECD). Flap endonuclease 1 (FEN1) plays an important role in the repair of oxidative DNA damage in the base excision repair pathway. We determined the association between two single nucleotide polymorphisms (SNPs), c.-441G>A (rs174538) and g.61564299G>T (rs4246215), in the FEN1 gene and the occurrence of KC and FECD. This study involved 279 patients with KC, 225 patients with FECD and 322 control individuals. Polymerase chain reaction (PCR) and length polymorphism restriction fragment analysis (RFLP) were applied. The T/T genotype of the g.61564299G>T polymorphism was associated with an increased occurrence of KC and FECD. There was no association between the c.-441G>A polymorphism and either disease. However, the GG haplotype of both polymorphisms was observed more frequently and the GT haplotype less frequently in the KC group than the control. The AG haplotype was associated with increased FECD occurrence. Our findings suggest that the g.61564299G>T and c.-441G>A polymorphisms in the FEN1 gene may modulate the risk of keratoconus and Fuchs endothelial corneal dystrophy.

[Not only optic neuropathy: new molecular and clinical aspects of OPA1 gene mutations]. / Nie tylko neuropatia wzrokowa: nowe aspekty molekularne i kliniczne mutacji w genie OPA1.

Autosomal dominant optic nerve atrophy is the most frequent dominantly inherited optic neuropathy. The main causesof the disease are OPA1 gene mutations, which are detected in about 60% of patients. Encoded by the nuclear genome the OPA1 protein plays an important role in a wide variety of processes crucial to the proper functioning of mitochondria, the role of OPAl in many of them has been discovered recently. A detailed study of patients with mutations in the OPA1 gene has shown that about 20% of them present symptoms of a multiple system disease, which may include hearing loss, progressive external ophthalmoplegia, ataxia, myopathy, peripheral neuropathy, spastic paraparesis and multiple sclerosis-like illness. This clinical manifestation is difficult to differentiate from other neurodegenerative diseases, that is why genetic testing is very important in order to determine the molecular basis of the disease in these patients.