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Khaled K Abu-Amero, Tahira Sultan, Saleh A Al-Obeidan, Altaf A Kondkar Glaucoma Research Chair, Department of Ophthalmology, College of Medicine, King Saud University, Riyadh, Saudi Arabia Abstract: Cytochrome P450 Family 1 Subfamily B Member 1 (CYP1B1; OMIM# 601771) gene encodes one of the cytochrome P450 family of enzymes. CYP1B1 mutations have been associated primarily with primary congenital glaucoma (PCG). Similar studies were reported in juvenile open-angle glaucoma, Rieger’s and Peters anomalies. Reports of likely pathogenic sequence alterations in families affected with adult-onset primary open-angle glaucoma (POAG) triggered this investigation. We screened unrelated POAG cases and healthy controls for mutations in CYP1B1 using automated Sanger sequencing to identify five known polymorphisms and one CYP1B1 mutation (p.G61E) in a heterozygous status. The p.G61E mutation is known to cause PCG in a homozygous or compound heterozygous form, and thus, its presence here in a heterozygous form indicates carrier status. These findings suggest that CYP1B1 may have no major role in the pathogenesis of POAG, at least, in the Saudi population. However, further investigations are needed to validate these findings in a larger cohort. Keywords: CYP1B1, genetics, mutation screening, POAG, Saudi Arabia

Altaf A Kondkar, Tahira Sultan, Faisal A Almobarak, Hatem Kalantan, Saleh A Al-Obeidan, Khaled K Abu-Amero Glaucoma Research Chair, Department of Ophthalmology, College of Medicine, King Saud University, Riyadh, Saudi Arabia Purpose: Retinal ganglion cell (RGC) death is a key feature of glaucoma. Elevated levels of tumor necrosis factor alpha (TNF-α), a pro-inflammatory cytokine, can induce RGC apoptosis and play a critical role in glaucomatous neurodegeneration. Based on the possible role of inflammation and oxidative stress in the pathogenesis of primary open-angle glaucoma (POAG), we investigated the association between plasma levels of TNF-α and POAG or its clinical indices in comparison to non-glaucomatous controls. Patients and methods: In a case–control retrospective cohort of 51 POAG cases and 88 controls, plasma TNF-α levels were measured using an enzyme-linked immunosorbent assay (ELISA). The assay was performed in duplicates on an automated ELISA analyzer. Results: Mean TNF-α level was significantly elevated in POAG cases (1.88 ± 2.17 pg/mL) than the controls (0.93 ± 1.49 pg/mL; p = 0.003). The overall dose–response trend was significant (Χ2 = 6.12, df = 2; p = 0.047). No statistical difference was seen in age, gender and systemic disease distribution. A modest negative and significant correlation was seen between TNF-α level and number of antiglaucoma medications, an important clinical index of POAG severity. Moreover, logistic regression analysis showed that the risk of POAG was most significantly affected by TNF-α level and not by age and sex. Conclusion: High systemic level of an inflammatory cytokine, TNF-α, is associated with POAG; however, its possible use as a biomarker for early glaucoma diagnosis and/or disease severity needs further investigation. Keywords: apoptosis, biomarker, cytokines, ELISA, inflammation, neurodegeneration, oxidative stress

Altaf A Kondkar,1 Taif A Azad,1 Faisal A Almobarak,1 Hatem Kalantan,1 Saleh A Al-Obeidan,1 Khaled K Abu-Amero1,2 1Glaucoma Research Chair, Department of Ophthalmology, College of Medicine, King Saud University, Riyadh, Saudi Arabia; 2Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, USA Background: Tumor necrosis factor alpha (TNF-α) is a pro-inflammatory cytokine, which plays a role in glaucomatous neurodegeneration. Based on the plausible role of inflammation in the pathogenesis of pseudoexfoliation glaucoma (PEG), we investigated whether there is any relationship between the levels of plasma TNF-α and PEG or any of its clinical indices in comparison to normal controls.Methods: The study was designed as a retrospective analysis. Plasma samples from 49 PEG patients and 88 non-glaucomatous controls were evaluated for TNF-α levels using an enzyme-linked immunosorbent assay (ELISA). The assay was performed in duplicates on a biochemical/ELISA analyzer.Results: The two study groups were similar in age, sex and systemic disease distribution. The mean TNF-α concentration was significantly higher in the PEG patients (5.54±4.58 pg/mL) than in the control subjects (0.93±1.49 pg/mL; 95% confidence interval [CI] =3.50–5.72; p=0.000). The overall dose–response trend was significant (χ2=57.07, df=2; p=0.000). A moderate positive and significant correlation was seen between TNF-α level and cup/disc ratio, an important clinical index for PEG. Besides, binary logistic regression analysis showed that the risk of PEG was most significantly affected by TNF-α level as compared to no association with age and sex. In receiver operating characteristic analysis, the area under the curve was 0.777 (95% CI =0.682–0.872) and statistically significant (p=0.000).Conclusion: Elevated systemic levels of inflammatory marker, TNF-α, are associated with PEG and may possibly serve as a biomarker for undiagnosed early glaucoma and/or as a marker for disease progression. Keywords: glaucoma, inflammation, oxidative stress, pseudoexfoliation, TNF-α

Ramzi Al Judaibi,1 Khaled K Abu-Amero,2,3 Jose Morales,1 Sami Al Shahwan,1 Deepak P Edward1,4 1King Khaled Eye Specialist Hospital, 2Department of Ophthalmology, College of Medicine, King Saud University, Riyadh, Kingdom of Saudi Arabia; 3Department of Ophthalmology, College of Medicine, University of Florida, Jacksonville, FL, USA; 4Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore MD, USA Purpose: Here, we present two patients with congenital anterior staphyloma, with mutations in the CYP1B1 gene. Methods: We reviewed the medical records, including the genetic analysis. Results: Two unrelated patients presented with congenital anterior staphylomas. Both patients showed mutations in the CYP1B1 gene. The first patient, the product of a consanguineous marriage, showed a homozygous misssense mutation g.3987G>A (p.G61E). The second patient had compound heterozygous misssense mutations [g.4160 G>T (p.A119S) and g.8131 C>G (p.L432V)]. Conclusion: CYP1B1 gene mutation may be associated with congenital anterior staphylomas. Keywords: mutation analysis, congenital glaucoma, consanguinity, congenital aphakia

Context.--Previous studies reported an association of certain polymorphisms in the lipoprotein lipase (LPL) gene with the risk of coronary artery disease (CAD); however, these studies were small and inconsistent. In addition, none of these studies attempted to establish such an association in the Arab population. Objective.--To determine whether 2 LPL polymorphisms (LPL-HindIII and LPL-PvuII located on introns 8 and 6, respectively, of the LPL gene) can be considered as independent risk factors or as predictors for CAD in Arabs. Design.--We used polymerase chain reaction and restriction enzyme digestion to determine the distribution of the LPL-HindIII and LPL-PvuII polymorphisms among healthy blood donors of Arabic origin (BD group) and angiographically confirmed CAD patients (CAD group) with identical ethnic backgrounds. Results.--For the HindIII genotypes, within the BD group (n = 410), the +/+ genotype was found in 206 individuals (50.2%), 173 (42.2%) carried the +/- genotype, and 31 (7.6%) carried the -/- genotype. Within the CAD group (n = 352), the +/+ genotype was found in 189 individuals (53.7%), 138 (39.2%) carried the +/- genotype, and 25 (7.1%) carried the -/- genotype. P values of .38, .45, and .92 were obtained for the +/+, +/-, and -/- genotypes, respectively. For the PvuII genotypes, within the BD group (n = 511), the +/+ genotype was found in 182 individuals (35.6%), 248 (48.5%) carried the +/- genotype, and 81 (15.9%) carried the -/- genotype. Within the CAD group (n = 431), the +/+ genotype was found in 138 individuals (32%), 225 (52.2%) carried the +/- genotype, and 68 (15.8%) carried the -/- genotype. P values of .28, .29, and .98 were obtained for the +/+, +/-, and -/- genotypes, respectively. The distribution and the allele frequency of these 2 LPL variants were similar in CAD and BD study groups and followed the Hardy-Weinberg equilibrium. Conclusion.--There was no difference in the distribution of both LPL polymorphisms between the healt... [ABSTRACT FROM AUTHOR]

Peroxisomes, single-membrane intracellular organelles, play an important role in various metabolic pathways. The translocation of proteins from the cytosol to peroxisomes depends on peroxisome import receptor proteins and defects in peroxisome transport result in a wide spectrum of peroxisomal disorders. Here, we report a large consanguineous family with autosomal recessive congenital cataracts and developmental defects. Genome-wide linkage analysis localized the critical interval to chromosome 12p with a maximum two-point LOD score of 4.2 (θ = 0). Next-generation exome sequencing identified a novel homozygous missense variant (c.653 T > C; p.F218S) in peroxisomal biogenesis factor 5 (PEX5), a peroxisome import receptor protein. This missense mutation was confirmed by bidirectional Sanger sequencing. It segregated with the disease phenotype in the family and was absent in ethnically matched control chromosomes. The lens-specific knockout mice of Pex5 recapitulated the cataractous phenotype. In vitro import assays revealed a normal capacity of the mutant PEX5 to enter the peroxisomal Docking/Translocation Module (DTM) in the presence of peroxisome targeting signal 1 (PTS1) cargo protein, be monoubiquitinated and exported back into the cytosol. Importantly, the mutant PEX5 protein was unable to form a stable trimeric complex with peroxisomal biogenesis factor 7 (PEX7) and a peroxisome targeting signal 2 (PTS2) cargo protein and, therefore, failed to promote the import of PTS2 cargo proteins into peroxisomes. In conclusion, we report a novel missense mutation in PEX5 responsible for the defective import of PTS2 cargo proteins into peroxisomes resulting in congenital cataracts and developmental defects.

Keratoconus (KC) is the most common corneal ectatic disorder affecting >300,000 people in the US. KC normally has its onset in adolescence, progressively worsening through the third to fourth decades of life. KC patients report significant impaired vision-related quality of life. Genetic factors play an important role in KC pathogenesis. To identify novel genes in familial KC patients, we performed whole exome and genome sequencing in a four-generation family. We identified potential variants in the PPIP5K2 and PCSK1 genes. Using in vitro cellular model and in vivo gene-trap mouse model, we found critical evidence to support the role of PPIP5K2 in normal corneal function and KC pathogenesis. The gene-trap mouse showed irregular corneal surfaces and pathological corneal thinning resembling KC. For the first time, we have integrated corneal tomography and pachymetry mapping into characterization of mouse corneal phenotypes which could be widely implemented in basic and translational research for KC diagnosis and therapy in the future.

Retinal dystrophies are one of the leading causes of pediatric congenital blindness. Leber's congenital amaurosis (LCA) encompasses one of the most severe forms of inherited retinal dystrophy responsible for early-onset childhood blindness in infancy. These are clinically characterized by nystagmus, amaurotic pupil response and markedly reduced or in most instances completely absent full-field electroretinogram. LCA exhibits immense genetic heterogeneity. With advances in next-generation genetic technologies, tremendous progress has been achieved over the last two decades in discovering genes and genetic defects leading to retinal dystrophies. Currently, 28 genes have been implicated in the pathogenesis of LCA and with initial reports of success in management with targeted gene therapy the disease has attracted a lot of research attention in the recent time. The review provides an update on genetic basis of LCA, scope for genetic testing and pharmacogenetic medicine in diagnosis and treatment of these diseases., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Importance: Primary open-angle glaucoma presents with increased prevalence and a higher degree of clinical severity in populations of African ancestry compared with European or Asian ancestry. Despite this, individuals of African ancestry remain understudied in genomic research for blinding disorders., Objectives: To perform a genome-wide association study (GWAS) of African ancestry populations and evaluate potential mechanisms of pathogenesis for loci associated with primary open-angle glaucoma., Design, Settings, and Participants: A 2-stage GWAS with a discovery data set of 2320 individuals with primary open-angle glaucoma and 2121 control individuals without primary open-angle glaucoma. The validation stage included an additional 6937 affected individuals and 14 917 unaffected individuals using multicenter clinic- and population-based participant recruitment approaches. Study participants were recruited from Ghana, Nigeria, South Africa, the United States, Tanzania, Britain, Cameroon, Saudi Arabia, Brazil, the Democratic Republic of the Congo, Morocco, Peru, and Mali from 2003 to 2018. Individuals with primary open-angle glaucoma had open iridocorneal angles and displayed glaucomatous optic neuropathy with visual field defects. Elevated intraocular pressure was not included in the case definition. Control individuals had no elevated intraocular pressure and no signs of glaucoma., Exposures: Genetic variants associated with primary open-angle glaucoma., Main Outcomes and Measures: Presence of primary open-angle glaucoma. Genome-wide significance was defined as P < 5 × 10-8 in the discovery stage and in the meta-analysis of combined discovery and validation data., Results: A total of 2320 individuals with primary open-angle glaucoma (mean [interquartile range] age, 64.6 [56-74] years; 1055 [45.5%] women) and 2121 individuals without primary open-angle glaucoma (mean [interquartile range] age, 63.4 [55-71] years; 1025 [48.3%] women) were included in the discovery GWAS. The GWAS discovery meta-analysis demonstrated association of variants at amyloid-β A4 precursor protein-binding family B member 2 (APBB2; chromosome 4, rs59892895T>C) with primary open-angle glaucoma (odds ratio [OR], 1.32 [95% CI, 1.20-1.46]; P = 2 × 10-8). The association was validated in an analysis of an additional 6937 affected individuals and 14 917 unaffected individuals (OR, 1.15 [95% CI, 1.09-1.21]; P < .001). Each copy of the rs59892895*C risk allele was associated with increased risk of primary open-angle glaucoma when all data were included in a meta-analysis (OR, 1.19 [95% CI, 1.14-1.25]; P = 4 × 10-13). The rs59892895*C risk allele was present at appreciable frequency only in African ancestry populations. In contrast, the rs59892895*C risk allele had a frequency of less than 0.1% in individuals of European or Asian ancestry., Conclusions and Relevance: In this genome-wide association study, variants at the APBB2 locus demonstrated differential association with primary open-angle glaucoma by ancestry. If validated in additional populations this finding may have implications for risk assessment and therapeutic strategies.

A case-control genetic association study was performed to investigate whether variant rs7916697 in atonal bHLH transcription factor 7 ( ATOH7 ), which has been previously reported to be associated with optic disc parameters and primary open angle glaucoma (POAG) in different ethnic groups, is a risk factor for POAG or any of its clinical phenotypes in a Saudi cohort. Genotyping of rs7916697 (G>A) variant was performed in 186 unrelated POAG cases and 171 unrelated nonglaucomatous controls of Saudi origin using real-time Taq-Man® assay. Genotypic and allelic association with POAG and its related clinical indices were evaluated. Demographic and systemic disease status did not differ significantly between POAG cases and controls. Association analysis between POAG cases and controls showed no significant genotype effect under additive (p=0.707), dominant (p=0.458), and recessive (p=0.554) models. Besides, the minor 'A' allele frequency was 0.39 in POAG cases and 0.36 in controls with no significant distribution (p=0.406). In addition, there was no significant difference between genotypes and clinical phenotypes such as intraocular pressure and cup/disc ratio within the POAG group, or any age and sex adjusted genotype effect on the disease outcome in regression analysis. Variant rs7916697 in ATOH7 is not associated with POAG or its clinical indices such as IOP and cup/disc ratio in a Saudi cohort.

Objective: Plexin domain containing 2 (PLXDC2), a cell surface transmembrane protein receptor for pigment epithelium derived factor, is expressed in many tissues including the eye. Polymorphism rs7081455 flanking PLXDC2 has been associated with primary open angle glaucoma (POAG) and its clinical phenotypes and may have a role in POAG. Rs7081455 was genotyped in POAG cases (n = 188) and non-glaucomatous controls (n = 164) of Saudi origin using Taq-Man ® to determine any association of this variant with POAG and its endophenotypes., Results: The risk variant, 'G' allele, frequency was 0.56 and 0.52 in controls and POAG cases, respectively (p = 0.197) with was no significant deviation from Hardy-Weinberg equilibrium. Genotype analysis between cases and controls revealed no significant distribution under additive (p = 0.482), dominant (p = 0.590) and recessive models (p = 0.228). In addition, glaucoma specific phenotypic traits such as intraocular pressure (IOP) and cup/disc ratio; and number of anti-glaucoma medications, used to assess severity of the disease, were also statistically non-significant. Furthermore, regression analysis showed no significant effect of age, sex and genotype on disease outcome. Rs7081455 was not associated with POAG or its clinical phenotypes such as IOP and cup/disc ratio and hence may not be a significant risk factor for POAG patients of Saudi origin.

Purpose: To report novel retinal findings in Kearns-Sayre syndrome and correlate degree of retinopathy with other clinical findings., Methods: Observational case series of patients from Saudi Arabia with retinal and neuroophthalmologic examinations, medical chart review, and mitochondrial genetic evaluation., Results: The three unrelated patients had progressive external ophthalmoplegia and pigmentary retinopathy bilaterally. Muscle biopsy in two of the cases revealed mitochondrial myopathy. All three had abnormal findings on neuroimaging and modestly reduced visual acuity in both eyes with a variable pigmentary retinopathy. One of the patients had bilateral subretinal fibrosis with a full-thickness macular hole in the right eye. All three patients had single, large-scale mitochondrial DNA (mtDNA) deletions (5.0-7.6 kb in size) with blood mtDNA heteroplasmy levels ranging from below 20% to 57%. Severity of pigmentary retinopathy did not correlate with severity of progressive external ophthalmoplegia, but did correspond grossly with electroretinographic abnormalities, just as the degree of ocular motility restriction and ptosis in each patient correlated with the size of their extraocular muscles on neuroimaging. In addition, the size of the single, large-scale mtDNA deletion and level of mtDNA heteroplasmy corresponded with degree of ocular motility restriction but not with severity of retinopathy., Conclusion: Subretinal fibrosis and macular hole are novel retinal observations which expand clinical profile in Kearns-Sayre syndrome. Genetic testing for mtDNA deletions and heteroplasmy in blood, muscle biopsy, careful ocular and retinal examination including electroretinography, and imaging are indispensable tests for this condition.

Background: The main unequivocal conclusion after three decades of phylogeographic mtDNA studies is the African origin of all extant modern humans. In addition, a southern coastal route has been argued for to explain the Eurasian colonization of these African pioneers. Based on the age of macrohaplogroup L3, from which all maternal Eurasian and the majority of African lineages originated, the out-of-Africa event has been dated around 60-70 kya. On the opposite side, we have proposed a northern route through Central Asia across the Levant for that expansion and, consistent with the fossil record, we have dated it around 125 kya. To help bridge differences between the molecular and fossil record ages, in this article we assess the possibility that mtDNA macrohaplogroup L3 matured in Eurasia and returned to Africa as basal L3 lineages around 70 kya., Results: The coalescence ages of all Eurasian (M,N) and African (L3 ) lineages, both around 71 kya, are not significantly different. The oldest M and N Eurasian clades are found in southeastern Asia instead near of Africa as expected by the southern route hypothesis. The split of the Y-chromosome composite DE haplogroup is very similar to the age of mtDNA L3. An Eurasian origin and back migration to Africa has been proposed for the African Y-chromosome haplogroup E. Inside Africa, frequency distributions of maternal L3 and paternal E lineages are positively correlated. This correlation is not fully explained by geographic or ethnic affinities. This correlation rather seems to be the result of a joint and global replacement of the old autochthonous male and female African lineages by the new Eurasian incomers., Conclusions: These results are congruent with a model proposing an out-of-Africa migration into Asia, following a northern route, of early anatomically modern humans carrying pre-L3 mtDNA lineages around 125 kya, subsequent diversification of pre-L3 into the basal lineages of L3, a return to Africa of Eurasian fully modern humans around 70 kya carrying the basal L3 lineages and the subsequent diversification of Eurasian-remaining L3 lineages into the M and N lineages in the outside-of-Africa context, and a second Eurasian global expansion by 60 kya, most probably, out of southeast Asia. Climatic conditions and the presence of Neanderthals and other hominins might have played significant roles in these human movements. Moreover, recent studies based on ancient DNA and whole-genome sequencing are also compatible with this hypothesis.

Aims: Variant rs10483727 in the SIX1/SIX6 locus has been significantly associated with primary open angle glaucoma (POAG) in multiple ethnic groups. We conducted a case-control study to investigate the association between this variant and POAG in a Saudi cohort., Materials and Methods: Polymorphism rs10483727 was genotyped by using a TaqMan ® assay in 186 subjects comprising 92 unrelated POAG cases and 94 controls all of Saudi origin., Results: The "C" allele frequency was 0.33 and 0.45 among POAG cases and controls, respectively (odds ratio [OR] = 0.58, 95% confidence interval [CI] = 0.38-0.89; p = 0.013), suggesting a protective effect; and the "T" allele was associated with increased susceptibility to POAG (OR = 1.7, 95% CI = 1.11-2.58; p = 0.013). Genotype distribution was also significantly associated with POAG (χ 2  = 6.41, df = 2, p = 0.041). Endophenotype traits such as intraocular pressure and cup/disk ratio did not show any significant genotype distribution in POAG cases. A binary logistic regression analysis used to evaluate the effects of age, gender, and genotype on the likelihood of having POAG showed that genotype distribution (p = 0.012) significantly affected the disease outcome as compared with age (p = 0.055) and sex (p = 0.432)., Conclusion: The "T" allele of the rs10483727 polymorphism is an independent significant risk factor for POAG in the Saudi population.

Aims: To conduct a case-control study to investigate the association between the polymorphism rs11656696 located in the growth arrest-specific 7 gene (GAS7)on human chromosome 17p13.1 and primary open angle glaucoma (POAG)., Methods: The polymorphism rs11656696 was genotyped using the TaqMan ® assay in 187 subjects comprising 92 unrelated POAG cases and 95 controls of Saudi Arabian origin., Results: Association analysis between cases and controls revealed no significant genotype distribution under additive (p = 0.225), dominant (p = 0.635), or recessive (p = 0.085) models. Moreover, the allele frequency distribution was also nonsignificant (p = 0.70). The minor "A" allele frequency was 0.35 and 0.41 among POAG cases and controls, respectively. In addition, specific clinical indices used to assess severity of glaucoma such as intraocular pressure (IOP), cup/disk ratio, and number of antiglaucoma medications also did not show any significant genotype distribution in POAG cases. Moreover, a binary logistic regression analysis did not show any significant effect of age, sex, or genotype on disease outcome., Conclusion: Polymorphism rs11656696 is not associated with POAG nor any of its endophenotypic traits such as IOP and cup/disk ratio and is thus not a risk factor for POAG in this Saudi cohort.

Objective: Polymorphism rs13334190 in the zinc finger protein 469 gene has been suggested to predispose toward a "thin" cornea, which then becomes keratoconic or is directly pathogenic. Thus, we genotyped polymorphism rs13334190 in 127 unrelated keratoconus cases and 168 control subjects from Saudi Arabia using Taq-Man ® assay., Results: The genotype frequency distribution did not deviate significantly from the Hardy-Weinberg equilibrium (p > 0.05). Overall, both the genotype and allele frequencies were not significantly different between cases and controls. A minor allele frequency of 0.068 was comparable to the aggregate rates ranging from 0.060 to 0.086 observed in other populations. Binary logistic regression analysis was performed to ascertain the effects of age, gender and genotype on the likelihood of having keratoconus. The analysis indicated that increased age was statistically significant (p = 0.000) and that females have a 2.19-fold increased risk (p = 0.018) of developing keratoconus. The genotype frequencies did not differ between the sporadic or familial keratoconus cases. Polymorphism rs13334190 is not an independent risk factor for keratoconus in the Saudi cohort.

Purpose: To evaluate the integrity of macular and temporomacular vasculature in nonproliferative diabetic retinopathy (NPDR) with noninvasive optical coherence tomography angiography (OCTA) and correlate perfusion indices with degree of NPDR., Methods: In this prospective observational cross-sectional study, 102 eyes with newly diagnosed NPDR (mild NPDR, 36; moderate NPDR, 21; severe NPDR, 13; NPDR with diabetic macular edema [DME], 32) underwent OCTA. Sixty eyes of normal subjects served as control. Degree of NPDR (based on Early Treatment Diabetic Retinopathy Study criteria) was confirmed with fluorescein angiography. Automated OCTA/split-spectrum amplitude decorrelation angiography software generated perfusion indices (vessel density and flow index) from images of the retina. The perfusion index of superficial and deep retinal plexuses was obtained in both perifoveal (central 1-3 mm) and parafoveal (3-6 mm) areas., Results: Deep plexus parafoveal vessel density was 25.23% (±6.1) in mild NPDR, 20.16% (±6.16) in moderate NPDR, 11.16% (±4.16) in severe NPDR, and 17.91% (±4.42) in NPDR + DME compared to normal subjects (36.93% [±8.1]; (p<0.01). Spearman correlation coefficient (r s ) between vessel density and level of NPDR severity in the parafoveal region showed inverse correlation for both superficial (r s -0.87; p = 0.083) and deep (r s -0.96; p = 0.017) plexus. Similarly, when vessel density of the perifoveal region was compared with level of NPDR severity, inverse correlation was noted in both superficial (r s -0.85; p = 0.08) and deep (r s -0.98; p = 0.011) plexus., Conclusions: Optical coherence tomography angiography clearly delineated the retinal microcirculation and allowed quantification of vascular perfusion of each layer. As diabetic retinopathy progressed, a decrease in perfusion index is more pronounced in the deep retinal plexus and precedes changes in superficial plexus.

Objective: Congenital fibrosis of the extraocular muscles type 1 (CFEOM1) is known to be caused by mutations in KIF21A or TUBB3 or other known genes (SALL4, CHN1, HOXA1). However, affected children may harbor other genetic defects. Therefore, a candidate gene analysis (KIF21A, TUBB3 SALL4, CHN1, HOXA1) and a high-resolution array comparative genomic hybridization (arrayCGH) was performed in two unrelated children with sporadic CFEOM1., Results: Two unrelated Saudi patients did not have any mutation(s) after sequencing the full coding regions of SALL4, CHN1, HOXA1, and TUBB3 genes; and exons 8, 20, and 21 of the KIF21A gene. However, arrayCGH revealed a 3.17 Kb deletion at chromosome 8p22 with copy number state equal to 1, indicating a heterozygous deletion. This deletion was absent in proband's mother or father or 220 unrelated healthy individuals of similar ethnicity. The deletion encompassed only one functional gene, GRHL2, which encodes a transcription factor. In humans, defects in this gene are a cause of non-syndromic sensorineural deafness, autosomal dominant type 28 (DFNA28). We speculate that GRHL2 gene may have a role in orbital innervations and the defect in this gene (deletion) may be related to the CFEOM1 phenotype in these two children.

Background: To investigate the association between polymorphism rs547984, located in close proximity to the Zona Pellucida Glycoprotein 4 (ZP4) gene on human chromosome 1q43 and primary open angle glaucoma (POAG)., Method: Polymorphism rs547984 was genotyped using Taq-Man® assay in 185 subjects comprising of 90 unrelated POAG cases and 95 controls of Saudi origin., Results: Association analysis between cases and controls revealed no significant genotype distribution under additive (p = 0.356), dominant (p = 0.517) and recessive (p = 0.309) models. Besides, the allele frequency distribution was also found to be non-significant (p = 0.70). The minor "A" allele frequency was found to be 0.49 and 0.50 among POAG cases and controls, respectively. In addition, specific clinical indices used to assess severity of glaucoma such as intraocular pressure (IOP), cup/disc ratio and number of anti-glaucoma medication also did not show any significant genotype distribution in POAG cases., Conclusion: Polymorphism rs547984 is neither associated with any clinical indices important for POAG such as IOP and cup/disc ratio nor is a risk factor for POAG in the Saudi cohort.

Background: The colonization of Eurasia and Australasia by African modern humans has been explained, nearly unanimously, as the result of a quick southern coastal dispersal route through the Arabian Peninsula, the Indian subcontinent, and the Indochinese Peninsula, to reach Australia around 50 kya. The phylogeny and phylogeography of the major mitochondrial DNA Eurasian haplogroups M and N have played the main role in giving molecular genetics support to that scenario. However, using the same molecular tools, a northern route across central Asia has been invoked as an alternative that is more conciliatory with the fossil record of East Asia. Here, we assess as the Eurasian macrohaplogroup R fits in the northern path., Results: Haplogroup U, with a founder age around 50 kya, is one of the oldest clades of macrohaplogroup R in western Asia. The main branches of U expanded in successive waves across West, Central and South Asia before the Last Glacial Maximum. All these dispersions had rather overlapping ranges. Some of them, as those of U6 and U3, reached North Africa. At the other end of Asia, in Wallacea, another branch of macrohaplogroup R, haplogroup P, also independently expanded in the area around 52 kya, in this case as isolated bursts geographically well structured, with autochthonous branches in Australia, New Guinea, and the Philippines., Conclusions: Coeval independently dispersals around 50 kya of the West Asia haplogroup U and the Wallacea haplogroup P, points to a halfway core area in southeast Asia as the most probable centre of expansion of macrohaplogroup R, what fits in the phylogeographic pattern of its ancestor, macrohaplogroup N, for which a northern route and a southeast Asian origin has been already proposed.

Background: To investigate whether SNP rs4986790 in toll-like receptors (TLRs) is a risk factor for primary open angle glaucoma (POAG) in a Saudi population., Materials and Methods: A cohort of 85 unrelated POAG patients and 95 unrelated control subjects from Saudi Arabia were genotyped utilizing Taq-Man® assay. The association between mutant genotypes and various clinical indices important for POAG was investigated., Results: Among cases, the normal pattern (A/A) was detected in 70 (82.4%) of the subjects, A/G in 14 (16.5%) and G/G in one subject only (1.2%). Among controls, prevalence of the genotype (A/A) was detected in 86 (90.5%), the (A/G) genotype in 8 (8.4%) and homozygous mutated genotype (G/G) in 1 (1.1%) subjects. Comparing cases to controls, the odds ratio of having heterozygous mutation (A/G) was 2.15 [95% CI: 0.853-5.417], which was not significant (p = 0.114). The odds ratio of having homozygous mutation (G/G) was 1.22 [95% CI: 0.075-19.99], which was statistically non-significant (p = 0.568). Likewise, the presence of the mutated allele (G) was non-significantly different between cases and controls (p = 0.154). Comparing cases to controls as regards co-morbidity with other systemic diseases, there were no statistically significant differences between groups in all assessed diseases except for a family history of glaucoma (p = 0.014) Conclusions: In conclusion, we could not detect any direct link between genotypes or allele frequencies of SNP rs4986790 in the TLR4 gene and POAG. In contrast, genotype (A/A) may be protective against POAG especially among individuals with no family history of glaucoma.

Background: To investigate whether polymorphism rs540782 on chromsome 1, in close proximity to the Zona Pellucida Glycoprotein 4 (ZP4) gene, is a risk factor for primary open angle glaucoma (POAG)., Method: The study genotyped 92 unrelated POAG cases and 95 control subjects from Saudi Arabia using Taq-Man® assay., Results: The genotype frequency distribution did not deviate significantly from the Hardy-Weinberg equilibrium (p > 0.05). Overall, both the genotype and allele frequencies were not significantly different between cases and controls. The minor 'C' allele frequency was 49.4%, which was comparable to the Japanese population and higher than the Indian and Afro-Caribbean populations. Similarly, no significant association was found between genotypes and systemic diseases and health awareness/behavior domain variables. Importantly, glaucoma specific indices, such as intraocular pressure, cup/disc ratio and number of anti-glaucoma medication, also showed no statistically significant effect of genotypes within POAG cases., Conclusion: Polymorphism rs540782 is not a risk factor for POAG in the Saudi cohort.

Sirtuins have received considerable attention since the discovery that silent information regulator 2 (Sir2) extends the lifespan of yeast. Sir2, a nicotinamide adenine dinucleotide- (NAD-) dependent histone deacetylase, serves as both a transcriptional effector and energy sensor. Oxidative stress and apoptosis are implicated in the pathogenesis of neurodegenerative eye diseases. Sirtuins confer protection against oxidative stress and retinal degeneration. In mammals, the sirtuin (SIRT) family consists of seven proteins (SIRT1-SIRT7). These vary in tissue specificity, subcellular localization, and enzymatic activity and targets. In this review, we present the current knowledge of the sirtuin family and discuss their structure, cellular location, and biological function with a primary focus on their role in different neuroophthalmic diseases including glaucoma, optic neuritis, and age-related macular degeneration. The potential role of certain therapeutic targets is also described., Competing Interests: The authors declare they have no competing interests.

Background: From a mtDNA dominant perspective, the exit from Africa of modern humans to colonize Eurasia occurred once, around 60 kya, following a southern coastal route across Arabia and India to reach Australia short after. These pioneers carried with them the currently dominant Eurasian lineages M and N. Based also on mtDNA phylogenetic and phylogeographic grounds, some authors have proposed the coeval existence of a northern route across the Levant that brought mtDNA macrohaplogroup N to Australia. To contrast both hypothesis, here we reanalyzed the phylogeography and respective ages of mtDNA haplogroups belonging to macrohaplogroup M in different regions of Eurasia and Australasia., Results: The macrohaplogroup M has a historical implantation in West Eurasia, including the Arabian Peninsula. Founder ages of M lineages in India are significantly younger than those in East Asia, Southeast Asia and Near Oceania. Moreover, there is a significant positive correlation between the age of the M haplogroups and its longitudinal geographical distribution. These results point to a colonization of the Indian subcontinent by modern humans carrying M lineages from the east instead the west side., Conclusions: The existence of a northern route, previously proposed for the mtDNA macrohaplogroup N, is confirmed here for the macrohaplogroup M. Both mtDNA macrolineages seem to have differentiated in South East Asia from ancestral L3 lineages. Taking this genetic evidence and those reported by other disciplines we have constructed a new and more conciliatory model to explain the history of modern humans out of Africa.

Aims: To investigate the association between the rs1900004 polymorphism in the atonal bHLH transcription factor 7 (ATOH7) gene and primary open angle glaucoma (POAG) in Saudi patients., Methods: Eighty-seven unrelated POAG cases and 94 unrelated control subjects of Saudi origin were genotyped utilizing a TaqMan ® assay. The association between mutant genotypes and POAG and its related clinical indices was investigated., Results: The genotype and allele frequencies of the polymorphism in ATOH7 did not show any statistically significant association with POAG compared to controls. The minor allele frequency was 0.32 in both cases and controls. None of the demographic, systemic diseases nor glaucoma-specific clinical indices such as intraocular pressure (IOP), cup/disc ratio, and number of antiglaucoma medication, showed any significant association with genotypes. Binary logistic regression analysis (adjusted for age and gender) showed that age was a marginally significant risk factor for the development of glaucoma (adjusted odds ratio = 1.1; 95% confidence interval = 1.079-1.158; p < 0.0001)., Conclusions: The study did not detect any direct link between genotype/allele frequency of rs1900004 in ATOH7 and POAG or its related clinical indices such as IOP and cup/disc ratio indicating that this polymorphism is not a risk factor for POAG in a Saudi cohort.

Aims: To investigate whether the polymorphism rs1063192 (A>G) in the cyclin-dependent kinase Inhibitor-2B (CDKN2B) gene is a risk factor for primary open-angle glaucoma (POAG)., Method: A case-control study was conducted wherein we genotyped 87 unrelated POAG cases and 94 control subjects from Saudi Arabia using the Taq-Man ® assay., Results: The minor allele frequency was 0.20 in POAG cases and 0.21 in controls. Both the genotype and allele frequencies were not significantly different between cases and controls. No significant association was found between genotypes and glaucoma clinical indices, except that the mutant homozygous genotype (G/G) was associated with the family history of glaucoma (p = 0.024)., Conclusion: Polymorphism rs1063192 in CDKN2B is not a risk factor for POAG in Saudi cohort.

Purpose: To assess the importance of monogenic mutations and chromosomal copy number variants (CNVs) in the occurrence of nonsyndromic bilateral Duane retraction syndrome (bilateral nsDRS)., Methods: The medical records of 12 patients with bilateral nsDRS were reviewed. Genes associated with DRS and associated congenital cranial dysinnervation disorders (SALL4, CHN1, HOXA1, TUBB3, and KIF21A) were sequenced in the standard fashion in each patient. Array comparative genomic hybridization (array CGH) was performed using Affymetrix Cytogenetics Whole-Genome 2.7M array, and the results were analyzed using Affymetrix Chromosome Analysis Suite v1.2. CNVs were assessed as unlikely to be pathologic if they were also present in the Database of Genomic Variants (DGV) or our local database of array CGH results in 150 normal individuals of Middle Eastern ethnicity., Results: No patient had a sequence mutation in SALL4, CHN1, HOXA1, TUBB3, or KIF21A. These 12 patients each had 36-42 chromosomal deletions and/or duplications (mean with standard deviation, 26.25 ± 6.77), but all of these CNVs were present either in the DGV or in our local database of normal individuals of similar ethnicity and, therefore, are considered nonpathogenic., Conclusions: The results reported here suggest that bilateral nsDRS is not usually associated with mutations in these genes or with chromosomal CNVs. Current evidence suggests other factors such as epigenetic and/or teratogenic abnormalities may be a potential cause of bilateral nsDRS., (Copyright © 2016 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.)

Background: We investigated whether polymorphism rs7555523 (A > C) in human transmembrane and coiled-coil domain 1 (TMCO1) gene is a risk factor for primary open angle glaucoma (POAG) in a Saudi cohort., Methods: A cohort of 87 unrelated POAG cases and 94 control subjects from Saudi Arabia were genotyped using Taq-Man® assay. The association of genotypes with POAG and other glaucoma specific clinical indices was investigated., Results: The genotype and allele frequency of polymorphism rs7555523 at TMCO1 did not show any statistically significant association with POAG as compared to controls. The minor allele frequency was 0.103 in cases and 0.085 in controls. Except for awareness of glaucoma (p = 0.036), no significant association of genotypes were seen with glaucoma specific clinical indices such as intraocular pressure (IOP), cup/disc ratio and number of anti-glaucoma medications used. Binary logistic regression analysis (adjusted for age and gender) showed that age was a significant indicator for the development of glaucoma in this group (adjusted odds ratio = 1.2; 95 % confidence interval = 1.078-1.157; p < 0.001)., Conclusion: Our study was unable to replicate the findings of previously reported association for polymorphism rs7555523 in TMCO1 with POAG and related clinical indices such as IOP and cup/disc ratio indicating that this variant is not a risk factor for POAG in the Saudi cohort.

Aims: To investigate whether single nucleotide polymorphism (SNP) rs4986791 (C>T) in the toll-like receptor 4 (TLR4) gene is a risk factor for primary open-angle glaucoma (POAG) in the Saudi population., Method: A case-control study was performed to genotype a cohort of 85 POAG patients and 95 matched healthy controls utilizing TaqMan(®). The association between mutant genotypes and various POAG clinical indices were investigated., Results: The wild-type (C/C), heterozygous (C/T), and homozygous (T/T) genotypes were observed in 85.9%, 12.9%, and 1.2% POAG cases, respectively, compared to 91.6%, 8.4%, and none, respectively, among controls. The minor allele frequency was 0.076 in cases and 0.042 in controls. Both the genotype and allele frequency among POAG cases and controls did not vary significantly. With the exception of family history of glaucoma (p = 0.032), no significant association of genotypes was seen with age, intraocular pressure, cup/disc ratio, number of antiglaucoma medications, and other systemic comorbidities among the POAG cases., Conclusion: We did not detect any direct association between genotypes or allele frequencies of SNP rs4986791 in the TLR4 gene and POAG.

Purpose: We describe the clinical features of a boy with bilateral Duane retraction syndrome (DRS), Duchenne muscular dystrophy (DMD), and other medical problems., Methods: The child was followed-up for five years; his chart was reviewed, including the results of a muscle biopsy and genetic testing. Multiplex ligation-dependent probe amplification (MLPA) was used to interrogate deletions/duplications in the dystrophin gene., Results: The proband had bilateral DRS with otherwise normal ocular motility; he also had developmental delay, mild mental retardation, and seizures. Clinical diagnosis of DMD included progressive proximal weakness, highly elevated creatine kinase levels, and a muscle biopsy showing significant dystrophic changes including contracted, degenerative, and regenerative fibers, and negative dystrophin immunostaining. MLPA documented duplication of exons 3 and 4 of the dystrophin gene., Conclusions: This boy is the third patient to be reported with DRS and DMD, the second with bilateral DRS and the only one with other neurologic features. Mutated dystrophin is present in extraocular muscles and in the central nervous system (CNS) in DMD, leaving open the question of whether this co-occurrence is the result of the genetic muscle abnormality, CNS effects caused by dystrophin mutations, or chance.

Resveratrol, a naturally occurring plant polyphenol found in grapes, is the principal biologically active component in red wine. Clinical studies have shown that resveratrol due to its potent anti-oxidant and anti-inflammatory properties are cardio-protective, chemotherapeutic, neuroprotective, and display anti-aging effects. Oxidative stress and inflammation play a critical role in the initiation and progression of age-related ocular diseases (glaucoma, cataract, diabetic retinopathy and macular degeneration) that lead to progressive loss of vision and blindness. In vitro and in vivo (animal model) experimental studies performed so far have provided evidence for the biological effects of resveratrol on numerous pathways including oxidative stress, inflammation, mitochondrial dysfunction, apoptosis, pro-survival or angiogenesis that are implicated in the pathogenesis of these age-related ocular disorders. In this review, we provide a brief overview of current scientific literature on resveratrol, its plausible mechanism(s) of action, its potential use and current limitations as a nutritional therapeutic intervention in the eye and its related disorders.

Aims: To investigate whether the single-nucleotide polymorphism (SNP) rs5743704 in the toll-like receptor 2 gene is associated with primary open-angle glaucoma (POAG) or any of its clinical indices in a Saudi cohort., Method: Ninety-five unrelated POAG cases and 95 controls of Saudi origin were genotyped utilizing a TaqMan(®) assay. The association between genotypes and various clinical indices important for POAG were investigated., Results: The genotypic and allelic frequencies among cases were not significantly different when compared to controls. The minor allele frequency was 0.021 in cases and 0.011 in controls. No significant association was seen with intraocular pressure and cup/disc ratio. However, carriers of the C/A genotype had higher number of anti-glaucoma medications compared to controls (p = 0.04)., Conclusion: SNP rs5773704 is not associated with POAG in a Saudi population. Despite sample size limitation, the association of the minor allele A with higher number of anti-glaucoma medications suggests a possible indirect role for this SNP in predicting disease severity.

Purpose: To report the results of molecular karyotyping for a dysmorphic girl with CYP1B1-negative primary congenital glaucoma from Saudi Arabia, where CYPB1 mutations account for over 90% of cases of primary congenital glaucoma and the remaining cases are idiopathic., Methods: CYP1B1 sequencing in the affected child; high-resolution array comparative genomic hybridization (array CGH) of the affected child and both unaffected parents (Affymetrix Cytogenetics Whole-Genome 2.7M array; Affymetrix Inc., Santa Clara, CA, USA)., Results: The girl did not harbor CYP1B1 mutation by Sanger sequencing. Array CGH revealed 2 de novo 7p heterozygous duplications (7p21 - 7p14, encompassing 223 genes, and 7p14-7p11.2, encompassing 225 genes) and a 4p homozygous microdeletion (4p14) encompassing one gene only, DTHD1., Conclusions: The fact that this dysmorphic girl is Saudi Arabian and has CYP1B1-negative primary congenital glaucoma suggests that her glaucoma phenotype is related to her de novo copy number variation. Loss or gain of one or more of the genes encompassed in the identified chromosomal areas may be associated with primary congenital glaucoma and/or other observed phenotypic features.

Background: Data on the pattern of epilepsy caused by metabolic disorders in the first 2 years of life are limited in developing countries. We aimed to identify the metabolic causes of epilepsy presented in the first 2 years of life and to describe their clinical, radiological, molecular, and electroencephalographic characteristics., Methods: This retrospective study was conducted between January 2010 and December 2011 at Saad Specialist Hospital (Al Khobar, Saudi Arabia). All patients younger than 2 years at the onset of epilepsy caused by metabolic disorders were reviewed. The International League Against Epilepsy definition was used, and febrile convulsion was excluded., Results: Of 221 children diagnosed with epilepsy in the first 2 years of life at our hospital, 24 had metabolic diseases. The characteristics of these 24 children included the following: consanguinity in 18 patients (75%), developmental delay in 13 (54%), generalized tonic-clonic seizures in 10 (42%), infantile spasms in four (17%), myoclonic in seven (29%), and focal seizures in three. The diagnosis was confirmed by DNA studies in 17 patients (71%) and enzyme assay in seven (29%). The main diagnoses were peroxisomal disorders (n = 3), nonketotic hyperglycinemia (n = 3), Menkes disease (n = 2), neuronal ceroid lipofuscinosis (n = 2), biotinidase deficiency (n = 2), and mitochondrial disorder (n = 2). The remaining patients had lysosomal storage disease, aminoacidopathy, fatty acid oxidation defects, and organic aciduria. Seizure freedom was achieved in one third of patients in this cohort., Conclusion: Different metabolic disorders were identified in this cohort, which caused different types of epilepsy, especially myoclonic seizures and infantile spasms., (Copyright © 2015. Published by Elsevier B.V.)

We report a 3-year-old Saudi boy with recurrent episodes of vomiting, poor feeding, and altered mental status accompanied by an intermittent mild hyperammonemia, and a large elevation of urinary orotic acid. Sanger sequencing of the ornithine transcarbamylase (OTC) gene revealed a novel hemizygous deletion at the fourth nucleotide of intron 4 (c.386+4delT) in the proband and his asymptomatic mother. This novel mutation in the OTC gene is responsible for the late-onset phenotype of OTC deficiency.

The aim of this report is to analyze the clinical features, and mutations of the methylmalonyl CoA mutase (MUT) gene in 2 patients with methylmalonic aciduria (MMA) attending King Saud University Medical City, Riyadh, Saudi Arabia in January 2014. The infants  aged 6 days (patient 1) and 3 months (patient 2) with sepsis-like picture, metabolic acidosis, and hyperammonemia were presented. Investigations revealed high propionylcarnitine (C3), elevated urinary methylmalonic acids, 3-hydroxypropionic acids and methylcitrate, consistent with MMA. Sanger-sequencing detected a homozygous novel mutation (c.329A&gt;G; p.Y110C) in the MUT gene in patient 1 and a heterozygous in parents. This mutation is predicted to have a damaging effect on the protein structure and function. In patient 2, we detected a novel homozygous nonsense mutation (c.2200C&gt;T; p.Q734X) and a heterozygous in parents. This mutation leads to a premature stop-codon at codon 734 of the MUT gene. We identified 2 novel mutations in the MUT gene causing isolated MMA.

Primary open angle glaucoma (POAG), a major cause of blindness worldwide, is a complex disease with a significant genetic contribution. We performed Exome Array (Illumina) analysis on 3504 POAG cases and 9746 controls with replication of the most significant findings in 9173 POAG cases and 26 780 controls across 18 collections of Asian, African and European descent. Apart from confirming strong evidence of association at CDKN2B-AS1 (rs2157719 [G], odds ratio [OR] = 0.71, P = 2.81 × 10(-33)), we observed one SNP showing significant association to POAG (CDC7-TGFBR3 rs1192415, ORG-allele = 1.13, Pmeta = 1.60 × 10(-8)). This particular SNP has previously been shown to be strongly associated with optic disc area and vertical cup-to-disc ratio, which are regarded as glaucoma-related quantitative traits. Our study now extends this by directly implicating it in POAG disease pathogenesis., (© The Author 2015. Published by Oxford University Press.)

Background: The modern human colonization of Eurasia and Australia is mostly explained by a single-out-of-Africa exit following a southern coastal route throughout Arabia and India. However, dispersal across the Levant would better explain the introgression with Neanderthals, and more than one exit would fit better with the different ancient genomic components discovered in indigenous Australians and in ancient Europeans. The existence of an additional Northern route used by modern humans to reach Australia was previously deduced from the phylogeography of mtDNA macrohaplogroup N. Here, we present new mtDNA data and new multidisciplinary information that add more support to this northern route., Methods: MtDNA hypervariable segments and haplogroup diagnostic coding positions were analyzed in 2,278 Saudi Arabs, from which 1,725 are new samples. Besides, we used 623 published mtDNA genomes belonging to macrohaplogroup N, but not R, to build updated phylogenetic trees to calculate their coalescence ages, and more than 70,000 partial mtDNA sequences were screened to establish their respective geographic ranges., Results: The Saudi mtDNA profile confirms the absence of autochthonous mtDNA lineages in Arabia with coalescence ages deep enough to support population continuity in the region since the out-of-Africa episode. In contrast to Australia, where N(xR) haplogroups are found in high frequency and with deep coalescence ages, there are not autochthonous N(xR) lineages in India nor N(xR) branches with coalescence ages as deep as those found in Australia. These patterns are at odds with the supposition that Australian colonizers harboring N(xR) lineages used a route involving India as a stage. The most ancient N(xR) lineages in Eurasia are found in China, and inconsistently with the coastal route, N(xR) haplogroups with the southernmost geographical range have all more recent radiations than the Australians., Conclusions: Apart from a single migration event via a southern route, phylogeny and phylogeography of N(xR) lineages support that people carrying mtDNA N lineages could have reach Australia following a northern route through Asia. Data from other disciplines also support this scenario.

Background: Keratoconus (KC) is the most common primary ectatic disease of the cornea and a major indication for corneal transplant. To date, limited KC-associated-risk loci have been identified. Association has recently been suggested between KC and 8 single nucleotide polymorphisms (SNPs) in the genomic regions of FNDC3B, COL4A3, MPDZ-NF1B, RXRA-COL5A1, LCN12-PTGDS, FOXO1, and BANP-ZNF469. These SNPs are associated with central corneal thickness (CCT), a known risk factor to KC. We are questioning whether these SNPs are significantly associated with KC in a Saudi Arabian population. The study included 108 unrelated KC cases and 300 controls. Patients were diagnosed with KC according to the Schimpff-flow based elevation map of the cornea. DNA genotyping was done using probe-based allelic discrimination TaqMan assays. Allele frequencies were compared between the cases and controls., Results: All SNPs were successfully genotyped with high efficiency (>95 %). The SNPs had no significant deviation in cases or controls from Hardy-Weinberg Equilibrium (HWE, p value > 0.05). None of the selected SNPs were significantly associated with KC in the Saudi Arabian population. However, we replicated the same trend of minor allele frequency (MAF) between cases and controls reported by a recent GWAS regarding the 5 SNPs rs4894535 (FNDC3B, chr3: 171995605), rs1536482 (RXRA-COL5A1, chr9: 137440528), rs7044529 (COL5A1, chr9: 137568051), rs11145951 (LCN12-PTGDS, chr9: 139860264), and rs2721051 (FOXO1, chr13: 41110884)., Conclusions: This is the first study investigating the association of these SNPs with KC in a population from Saudi Arabia. We replicated the same trend of MAF alteration of the association between the SNPs rs4894535 (FNDC3B, chr3: 171995605), rs7044529 (COL5A1, chr9: 137568051), rs11145951 (LCN12-PTGDS, chr9: 139860264) and rs2721051 (FOXO1, chr13: 41110884) and KC-risk as reported by a recently published GWAS. Consistently replicated population-based studies are necessary to identify and/or confirm genetic susceptibility for certain diseases. We acknowledge that the lack of significance in our study is due to our small sample size and insufficient statistical power; however our data still add to the body of evidence of potential KC-candidate SNPs. This report aims at supporting the possible association between CCT-associated SNPs and KC susceptibility.