Keratoconus is associated with increased copy number of mitochondrial DNA.

PURPOSE: To investigate the possible association of oxidative stress with keratoconus (KC), we estimated the changes in relative mitochondrial DNA (mtDNA) content. METHODS: The study included 119 patients with KC and 208 controls matched for gender, ethnicity, and systemic disease status. We selected controls who were older than the patients since the mtDNA copy number tends to increase with age. The age mean (standard deviation) was 26.4(7.6) and 54.5(14.4) years for the patients and controls, respectively. The relative mtDNA copy number was estimated with the real-time quantitative PCR (qPCR) method using ND1 as the mtDNA gene and human globulin (HGB; also known as the cytoglobin gene, CYGB) as the reference single-copy nuclear gene. RESULTS: The mean relative mtDNA content was significantly higher in patients with KC (1.20±0.45) than in the normal control subjects (1.04±0.36; p = 0.0004). Subjects with high mtDNA content (>1.259, i.e., greater than 75(th) percentile) were at an increased risk of the disease (odds ratio = 2.62, 95% confidence interval = 1.40 to 4.89; p =0.0025). CONCLUSIONS: Increased mtDNA content in patients with KC may indicate mitochondrial respiratory chain defects and thus mitochondrial-abnormality involvement.

Association between Polymorphism rs61876744 in PNPLA2 Gene and Keratoconus in a Saudi Cohort.

The genetic etiology of Keratoconus (KC) in Middle Eastern Arabs of Saudi origin is still unclear. A recent genome-wide study identified two significant loci in the region of PNPLA2 (rs61876744) and CSNK1E (rs138380) for KC that may be associated with KC in the Saudi population. In addition, polymorphisms in the apolipoprotein E (APOE) gene, namely, rs429358 and rs7412, responsible for APOE allelic variants ε2, ε3, and ε4, may influence KC via oxidative stress mechanism(s). Thus, we investigated the possible association of polymorphisms rs61876744, rs138380, rs429358, rs7412, and APOE genotypes in KC patients of the Saudi population. This study included 98 KC cases and 167 controls. Polymorphisms rs6187644 and rs138380 were genotyped using TaqMan assays, and rs429358 and rs7412 were genotyped via Sanger sequencing. Although the allele frequency of rs61876744(T) in PNPLA2 was a protective effect against KC (odds ratio (OR) = 0.64, 95% confidence interval (CI) = 0.44-0.93), the p-value (p = 0.020) was not significant for multiple testing correction (p = 0.05/4 = 0.015). However, rs6187644 genotype showed a modestly significant protective effect in the dominant model (OR = 0.53, 95% CI = 0.32-0.88, p = 0.013). Polymorphisms rs138380, rs429358, and rs7412 showed no significant allelic or genotype association with KC. However, the ε2-carriers (ε2/ε2 and ε2/ε3 genotypes) exhibited a greater than 5-fold increased risk of KC, albeit non-significantly (p = 0.055). Regression analysis showed no significant effect of age, gender, and the four polymorphisms on KC. Our results suggest that polymorphism rs6187644 in PNPLA2 might be associated with KC in the Middle Eastern Arabs of Saudi origin but warrant a large-scale association analysis at this locus.

Analysis of the VSX1 gene in keratoconus patients from Saudi Arabia.

PURPOSE: To screen the visual system homebox 1 (VSX1) gene in Saudi Arabian keratoconus patients. METHODS: We sequenced the entire coding region, exon-intron boundaries in clinically confirmed keratoconus patients (n=55) and 50 ethnically matched healthy controls. All cases and controls were unrelated. RESULTS: Sequencing VSX1 revealed the presence of five nucleotide changes, 3 of which were non-coding (g.8326 G>A, g.10945 G>T, and g.11059 A>C) and 2 were synonymous-coding sequence changes (g.5053 G>T and g.8222 A>G). All five sequence changes were benign polymorphisms with no apparent clinical significance. CONCLUSIONS: In our keratoconus cohort, no pathogenic VSX1 mutation(s) were identified.

High-resolution analysis of DNA copy number alterations in patients with isolated sporadic keratoconus.

PURPOSE: To determine whether patients with sporadic, non-familial keratoconus and no pathogenic mutations in the visual system homeobox 1 (VSX1) gene have evidence of chromosomal copy number alterations. METHODS: Twenty Saudi Arabian patients with isolated keratoconus, no family history of the disease and no mutations in VSX1 were recruited. Additionally, 10 ethnically-matched healthy controls were also recruited for this study. We screened patients for chromosomal copy number aberrations using the Agilent Human Genome CGH 244A Oligo Microarray Chip. RESULTS: None of the keratoconus patients screened had evidence of chromosomal copy number alterations when compared to normal ethnically matched controls. CONCLUSIONS: Chromosomal deletions and/or duplications were not detected in any of the patients tested here. Other chromosomal imbalances such as translocations, inversions, and some ploidies cannot be detected by current array CGH technology and other nuclear genetic or epigenetic factors cannot be excluded as a possible contributing factor to keratoconus pathogenesis.

Vogt-Koyanagi-Harada disease occurring during interferon-alpha and ribavirin therapy for chronic hepatitis C virus infection.

We report a case of Vogt-Koyanagi-Harada (VKH) disease in a 30-year-old patient who was receiving interferon-alpha and ribavirin therapy for chronic hepatitis C virus infection. The intraocular inflammation responded to systemic corticosteroid and mycophenolate mofetil treatment. Physicians should be aware of the association between interferon-alpha and ribavirin therapy for hepatitis C virus infection and the development of VKH disease.

Corneal elevation indices and pachymetry values of Saudi myopes using scheimpflug imaging.

OBJECTIVES: To report the corneal elevation and thickness values for Saudi myopes and to evaluate the differences between these parameters in subgroups of this target population. Methods: Pentacam corneal topographic maps of the right eyes of patients visiting Al-Hokama Eye Clinic, Riyadh, Saudi Arabia, a tertiary eye center between January 2009 and December 2015 were retrospectively analyzed in this cross-sectional study. The patients were grouped into 3 categories based on their spherical readings: mild (-0.25 to -2.75D), moderate (-3.00 to -5.75D), and severe (≥-6.00D). Furthermore, patients with cylindrical readings of ≥-1.00 diopter were categorized as having myopic astigmatism, whereas those with less than -1.00 cylindrical diopter were categorized as having simple myopia. Results: Our sample was comprised of 1,276 patients; 838 (65.7%) had simple myopia and 438 (34.3%) had myopic astigmatism. The values for the whole myopic group were as follows:  anterior corneal elevation (AE) at the apex= 2.60±1.48 (standard deviation), thinnest AE= 2.56±1.68, posterior elevation (PE) at the apex= 3.67±3.58, thinnest PE= 4.92±3.81, central pachymetry= 550.09±34.29, apical pachymetry=550.73±34.64, and thinnest pachymetry= 546.30±34.61. All of the measurements, except the apical PE and thinnest PE, were statistically significant across the simple and myopic astigmatism groups (p less than 0.05). Comparing the mild to moderate myopia groups revealed a significant difference in the apical AE (p=0.037). Moreover, the comparison between the mild and severe myopia groups revealed that the apical PE and the thinnest PE, as well as the central, apical, and thinnest pachymetry values were statistically significantly different (p less than 0.05). Conclusion: The corneal elevation indices and thicknesses specific to the Saudi myopes were found to be comparable to the international databases in terms of the elevation and thickness in some of the parameters.

Efficacy and safety of deep sclerectomy in uveitic glaucoma.

PURPOSE: To evaluate the safety and efficacy of deep sclerectomy with implant and mitomycin C in uveitic glaucoma. Design Prospective, noncomparative case study. PATIENTS AND METHODS: Nine patients (13 eyes) with uncontrolled uveitic glaucoma underwent deep sclerectomy with implant from 2002 to 2006. All patients had their uveitis controlled before and after surgery with anti-inflammatory therapy. Main outcome measures Control of intraocular pressure. A secondary outcome measure was the number of antiglaucoma medications required to achieve the desired intraocular pressure. Visual acuity and complication associated with the surgery were monitored. RESULTS: Mean follow-up was 21 months (range 12-54 months). Intraocular pressure (IOP) was reduced from a mean preoperative value of 28.7 mmHg to a mean postoperative value of 13.85 mmHg (Wilcoxon signed rank test P = 0.005). At the most recent visit, complete success was obtained in 84.6%, qualified success was obtained in 7.7%, and complete failure in 7.7%. Mean number of antiglaucoma medications was reduced from 3.07 to 0.2 (Wilcoxon signed rank test P = 0.001). Neodymium:YAG goniopuncture was performed in two eyes. Postoperative complications included transient hypotony with maculopathy in one eye, shallow choroidal effusions in two eyes, and progression of cataract in four eyes. CONCLUSION: Deep sclerectomy with implant in uveitic glaucoma appeared to be effective in controlling the IOP at short-term follow-up with no serious postoperative side-effects.

Analysis of the SOD1 Gene in Keratoconus Patients from Saudi Arabia.

We investigated Saudi patients with familial and sporadic Keratoconus for mutations in the Superoxide dismutase 1, soluble (SOD1) gene. We sequenced the entire coding region, exon-intron boundaries and intron 2 encompassing a 7-bp deletion in clinically confirmed Keratoconus patients (n = 55) and 100 ethnically matched healthy controls. All cases and controls were unrelated. Sequencing the SOD1 gene revealed the presence of four nucleotide changes and all were non-coding. Those were g.12035 C > A; g.13978 T > A; g.12037 G > A and g.11931 A > C with similar frequencies in patients and controls. All four sequence changes were benign polymorphisms with no apparent clinical significance. Additionally, the 7-bp deletion in intro2 reported previously, were not detected in any of our Keratocnus cohort. In our Keratoconus cohort, no pathogenic SOD1 mutation(s) was identified.

Long-term evaluation of efficacy and safety of deep sclerectomy in uveitic glaucoma.

PURPOSE: To assess long-term efficacy and safety of deep sclerectomy (DS) in uveitic glaucoma. PATIENTS AND METHODS: Thirty-three consecutive eyes (21 patients) with uveitic glaucoma underwent DS with mitomycin C and implant. Goniopuncture (GP) was done for uncontrolled postoperative intraocular pressure (IOP). RESULTS: Mean (± SD) follow-up was 33.2 (± 19.8) months. IOP was reduced from a mean preoperative value of 37.2 to postoperative value of 14.7 mmHg (p < 0.0001). Complete success was achieved in 24/33 eyes (72.7%); qualified success was obtained in 7/33 eyes (21.2%). Neodymium:YAG GP was performed in 12 eyes. Postoperative complications included cataract progression in 9 eyes, transient hypotony in 6 eyes, shallow choroidal effusions in 4 eyes, hypotony with persistent maculopathy in 1 eye, hyphema in 1 eye, and decompression retinopathy in 1 eye. CONCLUSION: DS is safe and effective in patients with uveitic open-angle glaucoma. However, laser goniopuncture is frequently needed to improve the outcome.

Genetics of keratoconus: where do we stand?

Keratoconus is a progressive thinning and anterior protrusion of the cornea that results in steepening and distortion of the cornea, altered refractive powers, and reduced vision. Keratoconus has a complex multifactorial etiology, with environmental, behavioral, and multiple genetic components contributing to the disease pathophysiology. Using genome-wide and candidate gene approaches several genomic loci and genes have been identified that highlight the complex molecular etiology of this disease. The review focuses on current knowledge of these genetic risk factors associated with keratoconus.

Mitochondrial sequence changes in keratoconus patients.

PURPOSE: We investigated whether a group of patients with keratoconus (KTCN) harbor mutations in the mitochondrial genome. METHODS: We sequenced the full mitochondrial genome in a group of Saudi patients with KTCN (n = 26) and 100 ethnically matched controls who had no KTCN by examination. RESULTS: A total of 10 KTCN patients (38.5%) had potentially pathogenic nonsynonymous mtDNA mutations. Of the nonsynonymous sequence changes detected, 4 (40%) were in Complex I, one was in the tRNA(Glutamine), one was in tRNA(Tryptophan), one was in tRNA(Asparagine), one was in tRNA(Histidine), and two were in the tRNA(Leucine2). One nonsynonymous sequence change was heteroplasmic, whereas all the remaining 9 were homoplasmic. These sequence changes were not detected in controls of similar ethnicity. Four sequence changes were novel (were not reported previously) and 5 were reported previously. Additionally, we detected 54 synonymous (does not result in an amino acid change) sequence changes with no pathologic significance. CONCLUSIONS: If our results are confirmed in a larger cohort and multiple ethnicities, then mtDNA mutation may be considered as a genetic risk factor contributing indirectly through the oxidative stress mechanism to the development and/or progression of KTCN.

Association of mitochondrial haplogroups H and R with keratoconus in Saudi Arabian patients.

PURPOSE: Keratoconic corneas exhibit more mitochondrial DNA (mtDNA) damage than do normal corneas and thus mtDNA may represent a potential candidate for genetic susceptibility studies in keratoconus. To test this hypothesis we determined mitochondrial haplogroups in Saudi patients with keratoconus and healthy controls of same ethnicity. METHODS: Mitochondrial haplogrouping was performed by polymerase chain reaction-based automated Sanger sequencing in 114 patients with keratoconus and 552 healthy controls. RESULTS: Mitochondrial haplogroups H and R were significantly overrepresented in patients with keratoconus (28.9% vs. 8.5%, P < 0.0001 and 17.5% vs. 3.1%, P < 0.0001, respectively) as compared to healthy controls. CONCLUSIONS: Our data suggest that individuals with mitochondrial haplogroups H and R are at increased risk to develop keratoconus. In addition, the results provide further evidence for a plausible role of mtDNA in keratoconus etiology.

The outcomes of mycophenolate mofetil therapy combined with systemic corticosteroids in acute uveitis associated with Vogt-Koyanagi-Harada disease.

PURPOSE: To study the effectiveness of mycophenolate mofetil (MMF) as first-line therapy combined with systemic corticosteroids in acute uveitis associated with Vogt-Koyanagi-Harada (VKH) disease. The outcomes in this group were compared with those of another group of patients with VKH disease who were treated with corticosteroid monotherapy or with delayed addition of immunomodulatory therapy. METHODS: This prospective study included 19 patients (38 eyes) diagnosed with acute uveitis associated with VKH disease. RESULTS: The mean follow-up period was 27.0 ± 11.1 months (range 16-54 months). Corticosteroid-sparing effect was achieved in all patients. The mean interval between starting treatment and tapering prednisone to 10 mg or less daily was 5.1 ± 1.2 months (range 3-7 months). Ten (53%) patients discontinued treatment without relapse of inflammation. The mean time observed of treatment was 17.3 ± 11.9 months (range 3-41.5 months). Visual acuity of 20/20 was achieved by 38% of the eyes in the corticosteroid group and by 74% in the corticosteroid + MMF group (p < 0.001). Recurrent inflammation of ≥3 times was reduced significantly (p = 0.0383) in the corticosteroid + MMF group (3%) as compared to corticosteroid group (18%). Development of all complications was significantly higher in the corticosteroid group (43%) compared with the corticosteroid + MMF group (8%) (p < 0.001). None of the eyes in the corticosteroid + MMF group developed 'sunset glow fundus'. CONCLUSIONS: Addition of MMF as first-line therapy to corticosteroids in patients with acute uveitis associated with VKH disease leads to significant reduction in recurrences of uveitis and development of late complications and significantly improves visual outcome.

Comparison of central corneal thickness measurements by Pentacam, noncontact specular microscope, and ultrasound pachymetry in normal and post-LASIK eyes.

PURPOSE: To compare central corneal thickness (CCT) measurements taken with Pentacam, noncontact specular microscope (NCSM), and ultrasound pachymetry (US) in normal and post-laser in situ keratomileusis (LASIK) eyes and to assess the agreement between the three devices. DESIGN: Prospective clinical trial. PATIENTS AND METHODS: Central corneal thickness (CCT) was measured in 94 eyes of normal volunteer and in 72 eyes of post-LASIK patients. Measurements were made with the three devices. RESULTS: In normal eyes, the mean (±SD) CCT taken with Pentacam, NCSM, and US was 552.6 ± 36.8 µm, 511.9 ± 38.6 µm, and 533.3 ± 37.9 µm, respectively. The average values of CCT taken with the three instruments were significantly different. In post-LASIK eyes the mean CCT with Pentacam, NCSM, and US was 483.02 ± 6.03 µm, 450.7 ± 5.3 µm, and 469.5 ± 5.8 µm, respectively. The average values of CCT taken were significantly different for Pentacam vs. NCSM (P = 0.046) and Pentacam vs. US (P = 0.02), but not significant for NCSM vs. US (P = 0.352). The Bland and Altman method for assessing clinical agreement between 3 instruments showed that in normal eyes, the mean values and paired differences of the three CCT devices were found to be statistically independent. In post-LASIK eyes, there was significant association between the difference and the mean of the Pentacam and NCSM, and US and NCSM. CONCLUSION: The three devices cannot be used interchangeably in normal and post-LASIK eyes. Pentacam tends to give significantly thicker reading than ultrasound pachymetry.