A multi-cohort genome-wide association study in African ancestry individuals reveals risk loci for primary open-angle glaucoma.

Primary open-angle glaucoma (POAG), the leading cause of irreversible blindness worldwide, disproportionately affects individuals of African ancestry. We conducted a genome-wide association study (GWAS) for POAG in 11,275 individuals of African ancestry (6,003 cases; 5,272 controls). We detected 46 risk loci associated with POAG at genome-wide significance. Replication and post-GWAS analyses, including functionally informed fine-mapping, multiple trait co-localization, and in silico validation, implicated two previously undescribed variants (rs1666698 mapping to DBF4P2; rs34957764 mapping to ROCK1P1) and one previously associated variant (rs11824032 mapping to ARHGEF12) as likely causal. For individuals of African ancestry, a polygenic risk score (PRS) for POAG from our mega-analysis (African ancestry individuals) outperformed a PRS from summary statistics of a much larger GWAS derived from European ancestry individuals. This study quantifies the genetic architecture similarities and differences between African and non-African ancestry populations for this blinding disease.

Elevated IOP following a bladder filling protocol: A case report.

Purpose: We describe a patient with elevated intraocular pressure (IOP) secondary to an oral water bolus and examine the utility of the water-drinking test. Observations: A 66-year-old male with a history of hypertension presented with headache, bilateral retro-orbital ache, and blurry vision. Symptoms began shortly after his radiation treatment for prostate cancer, for which he consumed a water bolus to fill his bladder 30 minutes prior to treatment initiation. On exam, he had bilateral elevated IOP that responded to topical IOP-lowering medications. Gonioscopy demonstrated open angles and fundus exam showed non-glaucomatous optic nerves with pronounced retinal venous tortuosity. The water-drinking test showed a peak intraocular pressure of 20 mmHg in the right eye (5 mmHg increase from baseline) and 23 mmHg in the left eye (8 mmHg increase from baseline), suggesting impairment of the outflow system in the left compared to the right eye. He was started on topical IOP-lowering therapy and followed in our clinic as a glaucoma suspect. Conclusions: Consumption of a water bolus can be associated with IOP elevation and may be a risk factor in patients with otherwise normal IOPs at risk for glaucoma. The water-drinking test was historically used as provocative testing for open-angle glaucoma and may have an updated role in evaluating at-risk patients without ocular hypertension.

Two Year Randomized Prospective Comparison of Ahmed Valve Versus Baerveldt Implant in Vitrectomized Eyes.

PRCIS: Ahmed Valve and Baerveldt shunt are efficacious options in vitrectomized eyes. Baerveldt implant achieves a lower mean intraocular pressure (IOP) at 2 years, with fewer medications and a higher percentage of medication-free patients. PURPOSE: To investigate and compare the efficacy and complications between Ahmed FP7 Glaucoma Valve (AGV) and Baerveldt 101-350 Glaucoma Implant (BGI) in vitrectomized eyes. MATERIALS AND METHODS: In this single-center randomized clinical trial, 43 vitrectomized eyes (39 patients) underwent glaucoma drainage device implantation. Eyes were randomized to receive either an AGV (FP7) or a BGI (101-350) and were followed for 2 years. Surgical success was defined as an IOP measurement≤18 mm Hg and≥5 mm Hg with or without glaucoma medication at 2 or more sequential visits after 3 months. The primary outcome was the comparison of the success rate at 2 years, while mean IOP, mean number of medications, and number of complications were considered secondary outcomes. RESULTS: Kaplan-Meier estimates of the 2-year success rates in IOP control after GDD implantation were similar between the 2 groups; AGV group 81.8% (95% CI: 67.2%-99.6%) and BGI group 85.7% (95% CI: 72.0%-100.0%), (log-rank test P value = 0.74). Patients in the BGI group had a statistically significant lower mean IOP compared with the AGV group in all follow-up visits at 2, 6, 12, and 24 months (11.62 vs. 17.45 mm Hg at the latter P value <0.001). The BGI group required a significantly lower number of medications for IOP control at the 2-year visit compared with the AGV group (0.76±0.99 vs. 1.5±1.06 P value = 0.02) but had a higher number of complications (62% vs. 41%, respectively). CONCLUSIONS: GDDs provide a viable solution for IOP control in vitrectomized eyes. Based on our prospective comparison, both Ahmed FP7 Glaucoma Valve and Baerveldt 101-350 Glaucoma Implant are efficacious options.

Resolution of COVID-19 induced anosmia following treatment with ST266.

Background: Persistent anosmia following COVID-19 disease affects a significant subset of patients. Symptoms of this olfactory dysfunction negatively impact patient quality of life, and effective treatments are lacking; therefore, novel therapies that restore the ability to smell have tremendous clinical potential. Case report: A 46-year-old female enrolled in a phase I clinical trial to assess the safety of targeted intranasal administration of a novel acellular secretome therapy (ST266) in patients diagnosed as glaucoma suspects. The patient reported greater than one year history of loss of smell that started following a presumed positive case of COVID-19. Following a 28-day treatment course of bilateral intranasal administration of ST266, the patient had resolution of her long-standing anosmia. Conclusion: This case demonstrates resolution of COVID-19-induced persistent anosmia after intranasal treatment with a novel acellular secretome therapy. Further studies are warranted to determine the potential of ST266 and its components to treat anosmia.

Self-identified Black Race as a Risk Factor for Intraocular Pressure Elevation and Iritis Following Prophylactic Laser Peripheral Iridotomy.

PRCIS: In primary angle closure suspects (PACS), self-identified Black race was a risk factor for intraocular pressure (IOP) elevation and iritis following laser peripheral iridotomy (LPI). Laser type was not associated with either immediate post-LPI IOP elevation or iritis in multivariate analysis. PURPOSE: The aim was to determine the impact of laser type and patient characteristics on the incidence of IOP elevation and iritis after LPI in PACS. MATERIALS AND METHODS: The electronic medical records of 1485 PACS (2407 eyes) who underwent either neodymium-doped yttrium-aluminum-garnet or sequential argon and neodymium-doped yttrium-aluminum-garnet LPI at the University of Pennsylvania between 2010 and 2018 were retrospectively reviewed. Average IOP within 30 days before LPI (baseline IOP), post-LPI IOP within 1 hour, laser type, laser energy, and the incidence of new iritis within 30 days following the procedure were collected. Multivariate logistic regression accounting for intereye correlation was used to assess factors associated with incidence of post-LPI IOP elevation and iritis, adjusted by age, sex, surgeon, and histories of autoimmune disease, diabetes, and hypertension. RESULTS: The incidence of post-LPI IOP elevation and iritis were 9.3% (95% confidence interval: 8.1%-10.5%) and 2.6% (95% CI: 1.9%-3.2%), respectively. In multivariate analysis, self-identified Black race was a risk factor for both IOP elevation [odds ratio (OR): 2.08 compared with White; P=0.002] and iritis (OR: 5.07; P<0.001). Higher baseline IOP was associated with increased risk for post-LPI IOP elevation (OR: 1.19; P<0.001). Laser type and energy were not associated with either post-LPI IOP elevation or iritis (P>0.11 for all). CONCLUSIONS: The incidence of immediate IOP elevation and iritis following prophylactic LPI was higher in Black patients independent of laser type and energy. Heightened vigilance and increased medication management before and after the procedure are suggested to help mitigate these risks.

Outcomes of Resident Performed Hydrus, iStent, and Kahook Glaucoma Procedures in a Predominantly African American Population.

PRCIS: This retrospective study characterized the efficacy and safety of 3 different microinvasive glaucoma surgery (MIGS) procedures in a predominantly African American population at the Philadelphia Veterans Affairs Hospital (Hydrus, Kahook, iStent), demonstrating no significant difference in intraocular pressure (IOP) and medication reduction between the 3 at long-term follow-up. PURPOSE: To compare the efficacy and safety of 3 different MIGS procedures in a predominantly African American population. METHODS: Retrospective cohort study of patients undergoing cataract extraction combined with 1 of 3 MIGS procedures (Hydrus, iStent, Kahook) at the Philadelphia Veterans Affairs Medical Center between January 1, 2015 and November 1, 2020. Analysis of variance and regression models were used to compare reduction in IOP and medication use among 3 MIGS types. RESULTS: A total of 123 eyes of 112 patients were included, including 56 (45.5%) eyes for Hydrus, 40 (32.5%) eyes for iStent, and 27 (22.0%) eyes for Kahook. Adjusted mean IOP reduction was greater for Hydrus at postoperative day 1 (-4.49 vs. -1.76 for iStent and -1.69 for Kahook, P=0.05 and greater for Kahook at postoperative week 1 (-2.53 vs. +0.70 for iStent vs. -1.41 for Hydrus, P=0.02), but did not differ significantly between MIGS types at subsequent postoperative visits (all P>0.05). In multivariable analysis, MIGS type was not significantly associated with reduction in IOP or medication use at 9 to 12 months postoperatively. There were no significant differences in complication rates across MIGS types. CONCLUSION: In this study, the difference in IOP lowering and medication reduction postoperatively between the Hydrus, iStent, and Kahook was not statistically significant after postoperative day 1. More studies are needed to evaluate outcomes of MIGS surgeries in glaucoma populations of different disease severity.

Netarsudil-associated epithelial keratopathy.

PURPOSE: To report 2 cases with a novel finding of bullous epithelial keratopathy associated with netarsudil use. OBSERVATIONS: A 72-year-old man with history of primary open angle glaucoma was started on netarsudil daily in both eyes for uncontrolled intraocular pressures despite treatment with latanoprost, brimonidine, and dorzolamide-timolol. One month later he presented with bilateral conjunctival hyperemia, predominantly inferior corneal epithelial bullae, and keratic precipitates without hypopyon. Netarsudil was discontinued, and the patient was started on topical steroids. One week later, the hyperemia and corneal edema had resolved while many small keratic precipitates persisted.A 29-year-old man with history of rubella-associated glaucoma and chronic postoperative inflammation on prednisolone was started on netarsudil in his left eye only for elevated intraocular pressures despite latanoprost, brimonidine, and dorzolamide-timolol. Two months later, he complained of eye pain and decreased vision since starting netarsudil. Examination revealed mild hyperemia and inferior corneal epithelial bullae without keratic precipitates. Netarsudil was discontinued, and two weeks later, conjunctival injection resolved and cornea cleared. CONCLUSIONS AND IMPORTANCE: Netarsudil ophthalmic solution 0.02% (Rhopressa) is a rho-kinase inhibitor recently approved for lowering intraocular pressure in open-angle glaucoma or ocular hypertension. As netarsudil continues to be increasingly used, physicians and patients need to be aware of this new possible adverse effect.

Primary Open-Angle African American Glaucoma Genetics (POAAGG) Study: gender and risk of POAG in African Americans.

The purpose of this study was to investigate the association between gender and primary open-angle glaucoma (POAG) among African Americans and to assess demographic, systemic, and behavioral factors that may contribute to differences between genders. The Primary Open-Angle African American Glaucoma Genetics (POAAGG) study had a case-control design and included African Americans 35 years and older, recruited from the greater Philadelphia, Pennsylvania. Diagnosis of POAG was based on evidence of both glaucomatous optic nerve damage and characteristic visual field loss. Demographic and behavioral information, history of systemic diseases and anthropometric measurements were obtained at study enrollment. Gender differences in risk of POAG were examined using multivariate logistic regression. A total of 2,290 POAG cases and 2,538 controls were included in the study. The percentage of men among cases was higher than among controls (38.6% vs 30.3%, P<0.001). The subjects' mean age at enrollment was significantly higher for cases compared to controls (70.2±11.3 vs. 61.6±11.8 years, P<0.003). Cases had lower rates of diabetes (40% vs. 46%, P<0.001), higher rates of systemic hypertension (80% vs. 72%, P<0.001), and lower body mass index (BMI) (29.7±6.7 vs. 31.9±7.4, P<0.001) than controls. In the final multivariable model, male gender was significantly associated with POAG risk (OR, 1.64; 95% CI, 1.44-1.87; P<0.001), after adjusting for age, systemic hypertension, diabetes, and BMI. Within the POAAGG study, men were at higher risk of having POAG than women. Pending genetic results from this study will be used to better understand the underlying genetic variations that may account for these differences.

Mitochondrial haplogroup L1c2 is associated with increased disease severity in African American patients with primary open-angle glaucoma.

OBJECTIVE: The purpose of this study is to evaluate the role mitochondrial inheritance plays in primary open-angle glaucoma (POAG) characteristics in African Americans. METHODS: POAG cases from the L1c2 and L1b mitochondrial haplogroups were compared in a retrospective case-case study. Twenty-six pairs of self-identified African American POAG cases from L1c2 and L1b mitochondrial haplogroups matched on age (mean [SD] = 71.2 [9.6] and 71.3 [9.6] years, respectively; p = 0.97), sex (21 female and 5 male pairs), and family history of glaucoma (positive in 15/26 [58%] pairs) were included. RESULTS: L1c2 subjects displayed higher vertical cup-to-disc ratio (0.75 [0.12] and 0.67 [0.16], respectively; p = 0.01, Bonferroni-corrected p = 0.08), worse pattern standard deviation on visual field (VF) testing (5.5 [3.5] and 3.5 [2.7]; p = 0.005, Bonferroni-corrected p = 0.02), and more severe glaucoma based on American Glaucoma Society staging criteria (p = 0.04, Bonferroni-corrected p = 0.32) compared to L1b subjects. L1c2 also trended towards worse mean deviation on VF compared to L1b (-8.2 [7.6] and -5.8 [6.8], respectively, p = 0.17). Best corrected visual acuity, central corneal thickness, maximum intraocular pressure (IOP), and cataract severity were comparable between L1c2 and L1b haplogroups (p ≥ 0.49), as was retinal nerve fiber layer thickness on optical coherence tomography (75.1 [14.1] and 75.1 [13.0]; p = 0.99). CONCLUSION: Results demonstrated worse glaucomatous cupping and more severe VF loss in the L1c2 compared to the L1b haplogroup despite comparable IOP. Findings implicate mitochondrial inheritance as a factor affecting POAG severity and may ultimately contribute to stratifying POAG patients into phenotypically and genotypically distinct subgroups.

Factors associated with participation by African Americans in a study of the genetics of glaucoma.

Objective: African Americans have been historically underrepresented in research studies. Our aim was to evaluate factors influencing enrollment in the Primary Open-Angle African American Glaucoma Genetics (POAAGG) study. Design: Patients approached to enroll in the POAAGG study were asked to complete a 15-item survey addressing demographic characteristics, knowledge of genetics and glaucoma, and opinions on human research. Survey responses were compared between subjects who enrolled (Enrollers) and did not enroll (Decliners) in the POAAGG study. Results: Enrollers (N = 190) were 3.7 years younger (P = 0.007) and had similar gender, education, and income level to Decliners (N = 117). Knowledge about genetics and glaucoma was similar between groups. Enrollers were more comfortable providing DNA for research studies (93.1% vs 54.1%; P < 0.001) and more likely to have participated in prior studies (P = 0.003) and consider participating in future studies (P < 0.001). Among Decliners, lack of time was the primary reason given for not enrolling. Conclusion: To increase participation of African Americans in genetic research studies, efforts should be made to raise comfort with DNA donation.

The MT-CO1 V83I Polymorphism is a Risk Factor for Primary Open-Angle Glaucoma in African American Men.

Purpose: We investigate the function of the V83I polymorphism (m.6150G>A, rs879053914) in the mitochondrial cytochrome c oxidase subunit 1 (MT-CO1) gene and its role in African American (AA) primary open-angle glaucoma (POAG). Methods: This study used Sanger sequencing (1339 cases, 850 controls), phenotypic characterization of Primary Open-Angle African American Glaucoma Genetics study (POAAGG) cases, a masked chart review of CO1 missense cases (V83I plus M117T, n = 29) versus wild type cases (n = 29), a yeast 2-hybrid (Y2H) cDNA library screen, and quantification of protein-protein interactions by Y2H and ELISA. Results: The association of V83I with POAG in AA was highly significant for men (odds ratio [OR] 6.5; 95% confidence interval [CI] 2.0-21.3, P = 0.0001), but not for women (OR 1.1; 95% CI, 0.62-2.00, P = 0.78). POAG cases having CO1 double missense mutation (V83I + M117T, L1c2 haplogroup) had a higher cup-to-disc ratio (0.77 vs. 0.71, P = 0.04) and significantly worse visual function (average pattern standard deviation, 6.5 vs. 4.3, P = 0.009; average mean deviation -10.4 vs. -4.5, P = 0.006) when compared to matched wild type cases (L1b haplogroup). Interaction of the V83I region of CO1 with amyloid beta peptide (Aß) was confirmed by ELISA assay, and this interaction was abrogated by V83I. A Y2H screen of an adult human brain cDNA library with the V83 region of CO1 as bait retrieved the UBQLN1 gene. Conclusions: The V83I polymorphism was associated strongly with POAG in AA men and disrupts Aß-binding to CO1. This region also interacts with a neuroprotective protein, UBQLN1.

Family History in the Primary Open-Angle African American Glaucoma Genetics Study Cohort.

PURPOSE: To determine the relationship between positive family history (FH) and primary open-angle glaucoma (POAG) diagnosis and clinical presentation in the Primary Open-Angle African American Glaucoma Genetics (POAAGG) cohort. METHODS: FH of POAG in first-degree relatives was assessed in 2365 subjects in the POAAGG cohort. A standardized interview was used to assess FH of glaucoma, demographic characteristics, lifestyle choices, and medical and ocular comorbidities. RESULTS: Positive FH was associated with increased risk of POAG (age-adjusted odds ratio and 95% confidence interval 3.4 [2.8, 4.1]). In age-adjusted analysis among POAG cases, positive FH was associated with younger age (P < .001), female sex (P < .001), hypertension (P = .006), use of hypertension medication (P = .03), and prior glaucoma surgery (P = .02). Cases with positive FH also had thicker retinal nerve fiber layers (P = .03). CONCLUSIONS: The risk conferred by positive FH suggests strong genetic underpinnings for some patients with this disease, which will be investigated by genome-wide association studies and whole exome sequencing. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

The SCHEIE Visual Field Grading System.

OBJECTIVE: No method of grading visual field (VF) defects has been widely accepted throughout the glaucoma community. The SCHEIE (Systematic Classification of Humphrey visual fields-Easy Interpretation and Evaluation) grading system for glaucomatous visual fields was created to convey qualitative and quantitative information regarding visual field defects in an objective, reproducible, and easily applicable manner for research purposes. METHODS: The SCHEIE grading system is composed of a qualitative and quantitative score. The qualitative score consists of designation in one or more of the following categories: normal, central scotoma, paracentral scotoma, paracentral crescent, temporal quadrant, nasal quadrant, peripheral arcuate defect, expansive arcuate, or altitudinal defect. The quantitative component incorporates the Humphrey visual field index (VFI), location of visual defects for superior and inferior hemifields, and blind spot involvement. Accuracy and speed at grading using the qualitative and quantitative components was calculated for non-physician graders. RESULTS: Graders had a median accuracy of 96.67% for their qualitative scores and a median accuracy of 98.75% for their quantitative scores. Graders took a mean of 56 seconds per visual field to assign a qualitative score and 20 seconds per visual field to assign a quantitative score. CONCLUSION: The SCHEIE grading system is a reproducible tool that combines qualitative and quantitative measurements to grade glaucomatous visual field defects. The system aims to standardize clinical staging and to make specific visual field defects more easily identifiable. Specific patterns of visual field loss may also be associated with genetic variants in future genetic analysis.

Cost and yield considerations when expanding recruitment for genetic studies: the primary open-angle African American glaucoma genetics study.

BACKGROUND: African Americans have been historically under-represented in genetic studies. More research is needed on effective recruitment strategies for this population, especially on approaches that supplement traditional clinic enrollment. This study evaluates the cost and efficacy of four supplemental recruitment methods employed by the Primary Open-Angle African American Glaucoma Genetics (POAAGG) study. METHODS: After enrolling 2304 patients from University of Pennsylvania ophthalmology clinics, the POAAGG study implemented four new recruitment methods to supplement clinic enrollment. These methods included: 1) outreach in the local community, 2) in-house screening of community members ("in-reach"), 3) expansion to two external sites, and 4) sampling of the Penn Medicine Biobank. The cost per subject was calculated for each method and enrollment among cases, controls, and suspects was reported. RESULTS: The biobank offered the lowest cost ($5/subject) and highest enrollment yield (n = 2073) of the four methods, but provided very few glaucoma cases (n = 31). External sites provided 88% of cases recruited from the four methods (n = 388; $85/subject), but case enrollment at these sites declined over the next 9 months as the pool of eligible subjects was depleted. Outreach and in-reach screenings of community members were very high cost for low return on enrollment ($569/subject for 102 subjects and $606/subject for 45 subjects, respectively). CONCLUSIONS: The biobank offered the most cost-effective method for control enrollment, while expansion to external sites was necessary to recruit richly phenotyped cases. These recruitment methods helped the POAAGG study to exceed enrollment of the discovery cohort (n = 5500) 6 months in advance of the predicated deadline and could be adopted by other large genetic studies seeking to supplement clinic enrollment.

Risk Factors Associated with Progression to Blindness from Primary Open-Angle Glaucoma in an African-American Population.

PURPOSE: To determine the risk factors associated with progression to blindness from primary open-angle glaucoma (POAG) in an African-American population. METHODS: This study examined 2119 patients enrolled in the Primary Open-Angle African-American Glaucoma Genetics (POAAGG) study. A total of 59 eyes were identified as legally blind as a result of POAG (cases) and were age-and sex-matched to 59 non-blind eyes with glaucoma (controls). Chart reviews were performed to record known and suspected risk factors. RESULTS: Cases were diagnosed with POAG at an earlier age than controls (p = 0.005). Of the 59 eyes of cases, 16 eyes (27.1%) presented with blindness at diagnosis. Cases had worse visual acuity (VA) at diagnosis (p < 0.0001), with VA worse than 20/40 conferring a 27 times higher risk of progression to blindness (p = 0.0005). Blind eyes also demonstrated more visual field defects (p = 0.01), higher pre-treatment intraocular pressure (IOP; p < 0.0001), and higher cup-to-disc ratio (p = 0.006) at diagnosis. IOP was less controlled in cases, and those with IOP ≥21 mmHg at more than 20% of follow-up visits were 73 times more likely to become blind (p < 0.0001). Cases missed a greater number of appointments per year (p = 0.003) and had non-adherence issues noted in their charts more often than controls (p = 0.03). However, other compliance data did not significantly differ between groups. CONCLUSION: Access to care, initial VA worse than 20/40, and poor control of IOP were the major risk factors associated with blindness from POAG. Future studies should examine earlier, more effective approaches to glaucoma screening as well as the role of genetics in these significantly younger patients who progress to blindness.

Association of primary open-angle glaucoma with mitochondrial variants and haplogroups common in African Americans.

PURPOSE: To estimate the population frequencies of all common mitochondrial variants and ancestral haplogroups among 1,999 subjects recruited for the Primary Open-Angle African American Glaucoma Genetics (POAAGG) Study, including 1,217 primary open-angle glaucoma (POAG) cases and 782 controls, and to identify ancestral subpopulations and mitochondrial mutations as potential risk factors for POAG susceptibility. METHODS: Subject classification by characteristic glaucomatous optic nerve findings and corresponding visual field defects, as defined by enrolling glaucoma specialists, stereo disc photography, phlebotomy, extraction of total DNA from peripheral blood or saliva, DNA quantification and normalization, PCR amplification of whole mitochondrial genomes, Ion Torrent deep semiconductor DNA sequencing on DNA pools ("Pool-seq"), Sanger sequencing of 3,479 individual mitochondrial DNAs, and bioinformatic analysis. RESULTS: The distribution of common African haplogroups within the POAAGG study population was broadly similar to prior surveys of African Americans. However, the POAG case population was found to be enriched in L1c2 haplogroups, which are defined in part by missense mutations m.6150G>A (Val83Ile, odds ratio [OR] 1.8, p=0.01), m.6253C>T (Met117Thr, rs200165736, OR 1.6, p=0.04), and m.6480G>A (Val193Ile, rs199476128, OR 4.6, p=0.04) in the cytochrome c oxidase subunit 1 (MT-CO1) gene and by a variant, m.2220A>G (OR 2.0, p=0.01), in MT-RNR2, which encodes the mitochondrial ribosomal 16s RNA gene. L2 haplogroups were predicted to be overrepresented in the POAG case population by Pool-seq, and the difference was confirmed to be significant with Sanger sequencing, that targeted the L2-associated variants m.2416T>C (rs28358580, OR 1.2, p=0.02) and m.2332C>T (OR 1.2, p=.02) in MT-RNR2. Another variant within MT-RNR2, m.3010G>A (rs3928306), previously implicated in sensitivity to the optic neuropathy-associated antibiotic linezolid, and arising on D4 and J1 lineages, associated with Leber hereditary optic neuropathy (LHON) severity, was confirmed to be common (>5%) but was not significantly enriched in the POAG cases. Two variants linked to the composition of the gut microbiome, m.15784T>C (rs527236194, haplogroup L2a1) and m.16390G>A (rs41378955, L2 haplogroups), were also enriched in the case DNA pools. CONCLUSIONS: These results implicate African mtDNA haplogroups L1c2, L1c2b, and L2 as risk factors for POAG. Approximately one in four African Americans have these mitochondrial ancestries, which may contribute to their elevated glaucoma risk. These haplogroups are defined in part by ancestral variants in the MT-RNR2 and/or MT-CO1 genes, several of which have prior disease associations, such as MT-CO1 missense variants that have been implicated in prostate cancer.

Saliva DNA quality and genotyping efficiency in a predominantly elderly population.

BACKGROUND: The question of whether DNA obtained from saliva is an acceptable alternative to DNA from blood is a topic of considerable interest for large genetics studies. We compared the yields, quality and performance of DNAs from saliva and blood from a mostly elderly study population. METHODS: Two thousand nine hundred ten DNAs from primarily elderly subjects (mean age ± standard deviation (SD): 65 ± 12 years), collected for the Primary Open-Angle African-American Glaucoma Genetics (POAAGG) study, were evaluated by fluorometry and/or spectroscopy. These included 566 DNAs from blood and 2344 from saliva. Subsets of these were evaluated by Sanger sequencing (n = 1555), and by microarray SNP genotyping (n = 94) on an Illumina OmniExpress bead chip platform. RESULTS: The mean age of subjects was 65, and 68 % were female in both the blood and saliva groups. The mean ± SD of DNA yield per ml of requested specimen was significantly higher for saliva (17.6 ± 17.8 µg/ml) than blood (13.2 ± 8.5 µg/ml), but the mean ± SD of total DNA yield obtained per saliva specimen (35 ± 36 µg from 2 ml maximum specimen volume) was approximately three-fold lower than from blood (106 ± 68 µg from 8 ml maximum specimen volume). The average genotyping call rates were >99 % for 43 of 44 saliva DNAs and >99 % for 50 of 50 for blood DNAs. For 22 of 23 paired blood and saliva samples from the same individuals, the average genotyping concordance rate was 99.996 %. High quality PCR Sanger sequencing was obtained from ≥ 98 % of blood (n = 297) and saliva (n = 1258) DNAs. DNA concentrations ≥10 ng/µl, corresponding to total yields ≥ 2 µg, were obtained for 94 % of the saliva specimens (n = 2344). CONCLUSIONS: In spite of inferior purity, the performance of saliva DNAs for microarray genotyping was excellent. Our results agree with other studies concluding that saliva collection is a viable alternative to blood. The potential to boost study enrollments and reduce subject discomfort is not necessarily offset by a reduction in genotyping efficiency. Saliva DNAs performed comparably to blood DNAs for PCR Sanger sequencing.

Primary Open-Angle Glaucoma in Individuals of African Descent: A Review of Risk Factors.

OBJECTIVE: To identify the major risk factors for primary open-angle glaucoma (POAG) in individuals of African descent. METHODS: We searched PubMed for relevant articles, with results spanning April 1947 to present. All abstracts were reviewed and, where relevant to POAG and race, articles were catalogued and analyzed. Additional sources were identified through citations in articles returned by our search. RESULTS: Numerous potential POAG risk factors were identified and organized into categories by demographics (age, sex, and skin color), lifestyle choices (smoking, alcohol), comorbidities (hypertension, diabetes, and obesity), ophthalmic findings (eye structure, central corneal thickness, corneal hysteresis, elevated intraocular pressure, myopia, cataract, and vascular abnormalities), family history, socioeconomic status, and adherence. Older age, male sex, lower central corneal thickness, decreased corneal hysteresis, elevated intraocular pressure, myopia, vascular abnormalities, and positive family history were definitively associated with increased risk of POAG. CONCLUSIONS: Individuals at greatest risk for POAG should be screened by an ophthalmologist to allow earlier detection and to slow disease progression. Further studies on the genetics of the disease will provide more insight into underlying pathologic mechanisms and could lead to improved therapeutic interventions. Continued research in urban areas with large populations of blacks is especially needed.