GJA3 Genetic Variation and Autosomal Dominant Congenital Cataracts and Glaucoma Following Cataract Surgery.

Importance: The p.Asp67Tyr genetic variant in the GJA3 gene is responsible for congenital cataracts in a family with a high incidence of glaucoma following cataract surgery. Objective: To describe the clinical features of a family with a strong association between congenital cataracts and glaucoma following cataract surgery secondary to a genetic variant in the GJA3 gene (NM_021954.4:c.199G>T, p.Asp67Tyr). Design, Setting, and Participants: This was a retrospective, observational, case series, genetic association study from the University of Iowa spanning 61 years. Examined were the ophthalmic records from 1961 through 2022 of the family members of a 4-generation pedigree with autosomal dominant congenital cataracts. Main Outcomes and Measures: Frequency of glaucoma following cataract surgery and postoperative complications among family members with congenital cataract due to the p.Asp67Tyr GJA3 genetic variant. Results: Medical records were available from 11 of 12 family members (7 male [63.6%]) with congenital cataract with a mean (SD) follow-up of 30 (21.7) years (range, 0.2-61 years). Eight of 9 patients with congenital cataracts developed glaucoma, and 8 of 8 patients who had cataract surgery at age 2 years or younger developed glaucoma following cataract surgery. The only family member with congenital cataracts who did not develop glaucoma had delayed cataract surgery until 12 and 21 years of age. Five of 11 family members (45.5%) had retinal detachments after cataract extraction and vitrectomy. No patients developed retinal detachments after prophylactic 360-degree endolaser. Conclusions and Relevance: The GJA3 genetic variant, p.Asp67Tyr, was identified in a 4-generation congenital cataract pedigree from Iowa. This report suggests that patients with congenital cataract due to some GJA3 genetic variants may be at especially high risk for glaucoma following cataract surgery. Retinal detachments after cataract extraction in the first 2 years of life were also common in this family, and prophylactic retinal endolaser may be indicated at the time of surgery.

Thrombospondin Mutations and Patients With Primary Congenital Glaucoma in a United States Population.

Mutations in the thrombospondin 1 ( THBS1 ) gene have been previously reported in primary congenital glaucoma (PCG) pedigrees that exhibit autosomal dominant inheritance with low penetrance. We sought to determine the role of THBS1 mutations in a cohort of 20 patients with PCG and 362 normal controls from Iowa using a combination of Sanger sequencing and whole exome sequencing. We detected 16 different THBS1 variants, including 4 rare, nonsynonymous variants (p.Thr611Met, p.Asn708Lys, p.Gln1089His, and p.Glu1166Lys). However, none of these variants were judged to be disease-causing mutations based on: 1) prevalence in cases and controls from Iowa, 2) prevalence in the public database gnomAD, 3) mutation analysis algorithms, and 4) THBS1 DNA sequence conservation. These results indicate THBS1 mutations are not a common cause of PCG in patients from Iowa and may be a rare cause of PCG overall.

Posterior Embryotoxon Revisited: An Immunohistologic Study.

PURPOSE: This series describes the immunopathologic features of posterior embryotoxon (PE) and demonstrates that it is not an anterior displaced Schwalbe's line as commonly described, but a peripheral corneal stromal nub variable in location with abnormal extracellular matrix. DESIGN: Case series. PARTICIPANTS: Archived specimens from patients with PE. METHODS: Sections from archived formalin-fixed, paraffin-embedded specimens (n = 9; 7 autopsy and 2 trabeculectomy specimens) were examined by light microscopy. Immunohistochemistry was performed on 5 specimens to characterize the extracellular matrix composition of PE. RESULTS: Posterior embryotoxon appeared as nubs of whorled collagen extending from the corneal stroma, lined in some instances, by Descemet membrane. These nubs were located anterior to Schwalbe's line (n = 4), posteriorly (n = 1), partially embedded in the trabecular meshwork (n = 1), or at Schwalbe's line (n = 2). Qualitatively, collagen I labeling of the PE stroma was similar or weaker than the corneal stroma, whereas collagen III staining was focal and slightly more intense compared with the corneal stroma. Lumican and keratan sulfate staining was similar or less intense in PE compared with the corneal stroma. MAIN OUTCOME MEASURES: Identify location of PE and its immunohistochemical features. CONCLUSIONS: In contrast to the widely accepted definition of PE as a prominent, anteriorly displaced Schwalbe line, histologic evidence suggests that it is a direct extension of the corneal stroma with variable locations that may displace the attenuated Descemet membrane when located anterior to or at Schwalbe's line. Immunohistochemical examination revealed that the composition of PE's extracellular matrix was similar to corneal stroma but with some variability in staining intensity.

Accurate Identification of the Trabecular Meshwork under Gonioscopic View in Real Time Using Deep Learning.

PURPOSE: Accurate identification of iridocorneal structures on gonioscopy is difficult to master, and errors can lead to grave surgical complications. This study aimed to develop and train convolutional neural networks (CNNs) to accurately identify the trabecular meshwork (TM) in gonioscopic videos in real time for eventual clinical integrations. DESIGN: Cross-sectional study. PARTICIPANTS: Adult patients with open angle were identified in academic glaucoma clinics in both Taipei, Taiwan, and Irvine, California. METHODS: Neural Encoder-Decoder CNNs (U-nets) were trained to predict a curve marking the TM using an expert-annotated data set of 378 gonioscopy images. The model was trained and evaluated with stratified cross-validation grouped by patients to ensure uncorrelated training and testing sets, as well as on a separate test set and 3 intraoperative gonioscopic videos of ab interno trabeculotomy with Trabectome (totaling 90 seconds long, 30 frames per second). We also evaluated our model's performance by comparing its accuracy against ophthalmologists. MAIN OUTCOME MEASURES: Successful development of real-time-capable CNNs that are accurate in predicting and marking the TM's position in video frames of gonioscopic views. Models were evaluated in comparison with human expert annotations of static images and video data. RESULTS: The best CNN model produced test set predictions with a median deviation of 0.8% of the video frame's height (15.25 µm) from the human experts' annotations. This error is less than the average vertical height of the TM. The worst test frame prediction of this model had an average deviation of 4% of the frame height (76.28 µm), which is still considered a successful prediction. When challenged with unseen images, the CNN model scored greater than 2 standard deviations above the mean performance of the surveyed general ophthalmologists. CONCLUSIONS: Our CNN model can identify the TM in gonioscopy videos in real time with remarkable accuracy, allowing it to be used in connection with a video camera intraoperatively. This model can have applications in surgical training, automated screenings, and intraoperative guidance. The dataset developed in this study is one of the first publicly available gonioscopy image banks (https://lin.hs.uci.edu/research), which may encourage future investigations in this topic.

Exome-based investigation of the genetic basis of human pigmentary glaucoma.

BACKGROUND: Glaucoma is a leading cause of visual disability and blindness. Release of iris pigment within the eye, pigment dispersion syndrome (PDS), can lead to one type of glaucoma known as pigmentary glaucoma. PDS has a genetic component, however, the genes involved with this condition are largely unknown. We sought to discover genes that cause PDS by testing cohorts of patients and controls for mutations using a tiered analysis of exome data. RESULTS: Our primary analysis evaluated melanosome-related genes that cause dispersion of iris pigment in mice (TYRP1, GPNMB, LYST, DCT, and MITF). We identified rare mutations, but they were not statistically enriched in PDS patients. Our secondary analyses examined PMEL (previously linked with PDS), MRAP, and 19 other genes. Four MRAP mutations were identified in PDS cases but not in controls (p = 0.016). Immunohistochemical analysis of human donor eyes revealed abundant MRAP protein in the iris, the source of pigment in PDS. However, analysis of MRAP in additional cohorts (415 cases and 1645 controls) did not support an association with PDS. We also did not confirm a link between PMEL and PDS in our cohorts due to lack of reported mutations and similar frequency of the variants in PDS patients as in control subjects. CONCLUSIONS: We did not detect a statistical enrichment of mutations in melanosome-related genes in human PDS patients and we found conflicting data about the likely pathogenicity of MRAP mutations. PDS may have a complex genetic basis that is not easily unraveled with exome analyses.

Aqueous Misdirection After Trabeculectomy in a Down Syndrome Patient With Angle-closure Glaucoma.

Down syndrome is a genetic disease caused by trisomy of chromosome 21 that is characterized by numerous systemic abnormalities including intellectual disability, stereotypical facies, and congenital heart malformations. Ocular abnormalities are commonly seen with Down syndrome including corneal disease (keratoconus), refractive error, and atypical irides (Brushfield spots). We report the first case of aqueous misdirection in a patient with Down syndrome after trabeculectomy. Patients with Down syndrome often have small, hyperopic eyes with narrow iridocorneal angles and may be at increased risk for aqueous misdirection associated with surgical procedures. Awareness of this risk may aid surgical planning and postoperative management.

Novel Intragenic PAX6 Deletion in a Pedigree with Aniridia, Morbid Obesity, and Diabetes.

Purpose: Aniridia is a rare congenital eye disease, characterized by a constellation of symptoms including hypoplastic irides, foveal hypoplasia, early cataract, corneal stem cell deficiency, and glaucoma. Large chromosomal deletions spanning the PAX6 gene cause WAGR syndrome (Wilms tumor, aniridia, genitourinary anomalies, and intellectual disability [formerly called mental retardation]). We describe clinical and genetic studies of a three-generation pedigree with aniridia along with additional systemic conditions (morbid obesity, diabetes) suggesting the possibility of a contiguous-gene syndrome like WAGR.Methods: Clinical records were obtained and DNA was prepared from blood samples from three of the four patients and tested for mutations in the coding sequences of the PAX6 gene. The index patient also had cardiomyopathy and was tested for known cardiomyopathy genetic mutations using a next-generation DNA sequencing assay.Results: We discovered a novel intragenic PAX6 mutation, a 16 bp heterozygous deletion c.203delCCAGGGCAATCGGTGG, with Sanger sequencing that is the likely cause of autosomal dominant aniridia in this pedigree. This PAX6 deletion causes a frameshift in predicted protein translation and a subsequent premature termination, p.Pro68Leufs*6. The PAX6 deletion was detected in all three available family members with aniridia, the index patient, his mother, and his maternal aunt but was not observed in the Exome Aggregation Consortium (ExAC) database. Targeted sequencing of known cardiomyopathy genes in the index patient identified a second mutation, a 1.7 Mp deletion that spans the MYBPC3 gene.Conclusions: We report a pedigree with aniridia and other systemic abnormalities that were initially suspicious for a contiguous-gene syndrome like WAGR. However, genetic analysis of the pedigree revealed two independent genetic abnormalities on chromosome 11p: 1) a novel PAX6 mutation, and 2) a large chromosome deletion spanning MYBPC3, a known cardiomyopathy gene. It is unclear if morbid obesity and type II diabetes mellitus have a related genetic cause.

Myocilin Mutations in Patients With Normal-Tension Glaucoma.

Importance: Mutations in the myocilin (MYOC) gene are the most common molecularly defined cause of primary open-angle glaucoma that typically occurs in patients with high intraocular pressures (IOP). One MYOC mutation, p.Gln368Ter, has been associated with as many as 1.6% of primary open-angle glaucoma cases that had a mean maximum recorded IOP of 30 mm Hg. However, to our knowledge, the role of the p.Gln368Ter mutation in patients with normal-tension glaucoma (NTG) with an IOP of 21 mm Hg or lower has not been investigated. Objective: To evaluate the role of the p.Gln368Ter MYOC mutation in patients with NTG. Design, Setting, and Participants: In this case-control study of the prevalence of the p.Gln368Ter mutation in patients with NTG, cohort 1 was composed of 772 patients with NTG and 2152 controls from the United States (Iowa, Minnesota, and New York) and England and cohort 2 was composed of 561 patients with NTG and 2606 controls from the Massachusetts Eye and Ear Infirmary and the NEIGHBORHOOD consortium. Genotyping was conducted using real-time polymerase chain reaction that was confirmed with Sanger sequencing, the imputation of genome-wide association study data, or an analysis of whole-exome sequence data. Data analysis occurred between April 2007 and April 2018. Main Outcomes and Measures: Comparison of the frequency of the p.Gln368Ter MYOC mutation between NTG cases and controls with the Fisher exact test. Results: Of 6091 total participants, 3346 (54.9%) were women and 5799 (95.2%) were white. We detected the p.Gln368Ter mutation in 7 of 772 patients with NTG (0.91%) and 7 of 2152 controls (0.33%) in cohort 1 (P = .03). In cohort 2, we detected the p.Gln368Ter mutation in 4 of 561 patients with NTG (0.71%) and 10 of 2606 controls (0.38%; P = .15). When the cohorts were analyzed as a group, the p.Gln368Ter mutation was associated with NTG (odds ratio, 2.3; 95% CI, 0.98-5.3; P = .04). Conclusions and Relevance: In cohorts 1 and 2, the p.Gln368Ter mutation in MYOC was found in patients with IOPs that were 21 mm Hg or lower (NTG), although at a frequency that is lower than previously detected in patients with higher IOP. These data suggest that the p.Gln368Ter mutation may be associated with glaucoma in patients with normal IOPs as well as in patients with IOPs that are greater than 21 mm Hg.

The Heritability of Pigment Dispersion Syndrome and Pigmentary Glaucoma.

PURPOSE: Pigment dispersion syndrome (PDS) and pigmentary glaucoma (PG) are presumed to be inherited in an autosomal dominant manner. We examine relatives of patients with PDS and PG in order to determine the heritability of these diseases. DESIGN: This was a prospective, cross-sectional study. METHODS: One hundred and one patients with PDS were prospectively recruited over 11 months. Four of the patients had PDS without ocular hypertension or glaucoma, 6 had PDS and ocular hypertension, and 91 had PG. Criteria for PDS were 2 of 3 signs: Krukenberg spindle, midperipheral iris transillumination defects, and/or heavy trabecular meshwork pigmentation. Criteria for PG were PDS and 2 of 3 signs: intraocular pressure >21 mm Hg, glaucomatous optic nerve damage, and/or glaucomatous visual field loss. Ninety-nine first-degree relatives living within a 100-mile radius of Iowa City, Iowa were examined in the clinic to determine the probability of familial transmission. RESULTS: A total of 10 of 99 (10.10%) first-degree relatives were diagnosed with PDS (1 with PDS alone, 2 with PDS and ocular hypertension, and 7 with PG). Seven families with ≥2 affected members were identified. The majority of affected family members (8/10) showed moderate to heavy trabecular meshwork pigmentation and either Krukenberg spindle or transillumination defects. CONCLUSIONS: Most of the cases of PDS in our study were sporadic, and the risk to first-degree relatives is lower than previously reported. However, there are families with apparent autosomal dominant inheritance of PDS in which the risk to relatives may be high.

Histochemical Analysis of Glaucoma Caused by a Myocilin Mutation in a Human Donor Eye.

Objective: Mutations in myocilin (MYOC) may cause either juvenile open angle glaucoma (JOAG) or adult-onset primary open angle glaucoma (POAG). MYOC encodes a glycoprotein that is normally secreted from trabecular meshwork cells that regulate intraocular pressure. Prior in vitro, transgenic rodent, and organ culture experiments have suggested that abnormal accumulation of MYOC protein within trabecular meshwork cells is a key step in glaucoma pathophysiology. We investigated the pathogenesis of MYOC glaucoma by examining a donor eye from a patient with JOAG caused by a Tyr437His MYOC mutation. Design: Case-control, immunohistochemical study of a donor eye from a patient with JOAG caused by a Tyr437His MYOC mutation and age-matched control donor eyes. Subjects: An eye from a 59-year-old male with JOAG caused by a Tyr437His MYOC mutation and eyes from five donors (ages 51-66) with no known ocular disease were examined. Methods: Frozen fixed sections of the iridocorneal angle were prepared from the donor eyes of the MYOC glaucoma patient and control eyes. We used antibodies directed against MYOC, collagen IV, and BiP/GRP78 as well as wheat germ agglutinin and concanavalin A lectins to localize MYOC protein in the trabecular meshwork. Main Outcome Measure: Qualitative comparison of MYOC protein labeling and localization in the trabecular meshwork of donor eyes from a glaucoma patient with a MYOC mutation and from control subjects. Results: Using immunohistochemistry, we detected more abundant MYOC protein within the trabecular meshwork of the MYOC glaucoma patient's eye than in control eyes. We further localized MYOC protein within the trabecular meshwork cells of the MYOC glaucoma patient's eye by co-labeling with the endoplasmic reticulum (ER) marker GRP78 (BiP). Little to no MYOC was identified within the trabecular meshwork cells of control eyes. Minimal extracellular MYOC was detected in both MYOC glaucoma eyes and control eyes. Conclusions: This is the first histopathological analysis of an eye from a glaucoma patient with a MYOC mutation. Furthermore, this analysis supports our model of MYOC-associated glaucoma, in which MYOC mutations cause abnormal intracellular retention of MYOC within the ER of trabecular meshwork cells as a key step towards development of glaucoma.