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PubMed2026

A Comprehensive Assessment of the Shared Genetic Architecture between Myopia and Open-Angle Glaucoma.

OBJECTIVE: Individuals with high myopia have an increased prevalence of open-angle glaucoma (OAG). We aim to clarify the possibly shared genetic architecture of myopia and OAG, in particular in high myopes with myopic macular degeneration (MMD), where OAG screening is highly challenging. DESIGN: Individual participant data meta-analysis of one-sample Mendelian randomization analyses and pleiotropic analysis under a composite null hypothesis. PARTICIPANTS: A total of 34 825 participants from 6 population-based cohort studies and 1 high myopia case-control study, including 708 OAG and 1953 high-myopia cases. METHODS: First, we calculated and validated genetic risk scores (GRSs) for OAG and myopia in each cohort. We subsequently meta-analyzed linear and logistic regression models for the association of a myopia GRS with OAG, intraocular pressure (IOP), and vertical cup-to-disc ratio (VCDR), and the association of an OAG-GRS with high myopia, axial length, and spherical equivalent. We stratified the analysis of OAG in different stages of axial elongation, and in high myopes with or without MMD. Pleiotropic analysis under a composite null hypothesis was applied to genome-wide association study summary statistics. MAIN OUTCOME MEASURES: Odds ratio (OR) of OAG and high myopia, and mean difference in IOP, VCDR, axial length, and spherical equivalent. RESULTS: One standard deviation (SD) increase in myopia GRS was associated with an OR (95% CI) of 1.18 (1.09, 1.28) for OAG, a beta (95% CI) of 0.04 (0.00, 0.08) mmHg in IOP, and of 0.005 (0.003, 0.007) in VCDR. The OAG-GRS was not significantly associated with high myopia compared to emmetropes, but a 1 SD increase was associated with a beta (95% CI) of 0.05 (0.01, 0.08) mm in axial length and of -0.05 (-0.10, -0.00) diopters in spherical equivalent. One SD increase in OAG-GRS had a substantially larger effect on OAG in high myopes with MMD, with an OR (95% CI) of 3.83 (1.89, 7.78) compared to 1.55 (1.24, 1.94) in emmetropes. Finally, we identified 95 independent pleiotropic single-nucleotide polymorphisms (SNPs). CONCLUSIONS: There is strong evidence for pleiotropy between myopia and OAG. Further research into the biological mechanisms of the identified pleiotropic SNPs is needed. An OAG-GRS might help to clinically estimate OAG risk, in particular in individuals with MMD. FINANCIAL DISCLOSURES: Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Axial length↗

PubMed2026

Deciphering the Microbiome-Gut-Eye Axis: A Mendelian Randomization Analysis of the Causal Influence of Gut Microbiota on Myopia.

INTRODUCTION: The intricate relationship between the gut microbiome and myopia is increasingly recognized, underscoring the need to explore its causal dynamics. Despite emerging evidence, the influence of Gut Microbiota (GM) on ocular development remains underexplored. METHODS: This study utilized Mendelian Randomization (MR) to investigate the causal impact of GM on the development of myopia. Instrumental variables (IVs) were identified from Genome-Wide Association Studies (GWAS), focusing on genetic variants significantly associated with microbiome composition. A comprehensive array of MR techniques was applied to ensure a robust estimation of causal effects and to adjust for potential confounders and pleiotropy. RESULTS: The Inverse-Variance Weighted (IVW) method was used to identify significant associations between GM and myopia. Increased risk of myopia was linked to the class Betaproteobacteria (OR=1.01, 95% CI 1.004-1.017, P=0.003), the order Burkholderiales (OR=1.009, 95% CI 1.001-1.016, P=0.02), the family Oxalobacteraceae (OR=1.005, 95% CI 1.001-1.01, P=0.023), and several genera including Eubacterium xylanophilum group (OR=1.007, 95% CI 1.001-1.013, P=0.033), and Bifidobacterium (OR=1.005, 95% CI 1-1.01, P=0.038). Protective effects were noted for the order Mollicutes RF9 (OR=0.994, 95% CI 0.99-0.999, P=0.014), the genus Allisonella (OR=0.996, 95% CI 0.993-0.999, P=0.019), the genus Lachnospiraceae UCG001 (OR=0.994, 95% CI 0.989-1, P=0.045), and the family Enterobacteraceae (OR=0.991, 95% CI 0.982-1, P=0.047) and order Enterobacteriales (OR=0.991, 95% CI 0.982-1, P=0.047). Sensitivity analyses further confirmed the robustness of these findings. DISCUSSION: This study provides causal evidence for the "Microbiome-Gut-Eye Axis" in myopia development, identifying specific gut microbiota that influence myopia risk. These findings suggest potential for microbiota-targeted interventions, warranting further research in diverse populations. CONCLUSIONS: The findings support the "Microbiome-Gut-Eye Axis" as a potential factor in myopia pathogenesis and highlight microbiota-targeted interventions as novel therapeutic strategies for managing myopia. This study lays the groundwork for further research on how modifying GM can influence eye health and offers new perspectives on preventive health strategies.

Humans↗

PubMed2026

Identifying potential therapeutic targets for high myopia via a case-control study and Mendelian randomisation analyses of the human blood metabolome.

BACKGROUND: High myopia increases the risk of pathological ocular changes that may lead to irreversible vision loss. Therefore, the identification of potential biomarkers and therapeutic targets for high myopia is essential for early intervention and prevention. METHODS: Summary statistics for 122 blood metabolites were obtained from three genome-wide association studies (GWASs), whereas data on high myopia were derived from a large GWAS conducted with 50,372 participants from the UK Biobank. Mendelian randomisation (MR) analyses were conducted to assess the causal relationships between blood metabolites and high myopia. A real-world case-control study was conducted to validate the causal associations identified in the MR analyses. RESULTS: The systematic MR analysis identified 5 blood metabolites as both biomarkers and potential drug targets for high myopia, including glutamine (odds ratio [OR]: 0.98, 95% confidence interval [CI]: 0.97-1.00), tyrosine (OR: 0.98; 95% CI: 0.97-0.99), degree of unsaturation (OR: 0.98, 95% CI: 0.98-0.99), docosahexaenoic acid (DHA) (OR: 0.99; 95% CI: 0.98-1.00) and isobutyrylcarnitine (OR: 1.09, 95% CI: 1.05-1.13). The case-control study indicated that the levels of glutamine (OR = 0.76, 95% CI: 0.58-0.98) and tyrosine (OR = 0.72, 95% CI: 0.55-0.94) were significantly associated with a decreased risk of high myopia. CONCLUSIONS: Systematic MR analysis suggested that glutamine, tyrosine, the degree of unsaturation, DHA, and isobutyrylcarnitine may represent promising drug targets for high myopia prevention. Further investigations are needed to validate the therapeutic efficacy and elucidate the underlying mechanisms involved.

Humans↗

PubMed2026

Risk Factors and Predictive Model for Postoperative High Myopia in Children Undergoing Congenital Cataract Surgery With Intraocular Lens Implantation.

PURPOSE: To identify risk factors associated with the development of high myopia following congenital cataract surgery and to establish a robust predictive model. DESIGN: Retrospective clinical cohort study. SUBJECTS: This retrospective study included 106 pediatric patients who underwent congenital cataract surgery with primary IOL implantation (mean follow-up 8.19 years). The model was externally validated in an independent cohort of 72 patients with a mean follow-up of 7.83 years. METHODS: Preoperative and postoperative ocular biometric parameters were collected. Risk factors for postoperative high myopia were analyzed using Cox proportional hazards regression, which served as the basis for model construction. The predictive performance of the model was rigorously evaluated for discrimination and calibration. Discriminative ability was quantified using Harrell's C-index and the area under the receiver operating characteristic curve (AUC). Model calibration was assessed via calibration plots by comparing predicted probabilities with actual observed outcomes. Internal validation was performed using a bootstrapping method (500 iterations) to ensure model stability and adjust for potential overfitting. RESULTS: An initial postoperative refraction of <+0.75D, and a higher IOL Power to Axial length Ratio (IOL/AL ratio) were identified as significant risk factors for the development of postoperative high myopia. Shorter preoperative axial length was associated with a greater magnitude of postoperative myopic shift. The predictive model demonstrated robust performance, achieving a C-index of 0.711 (internal validation C-index: 0.713). The area under the receiver operating characteristic curve (AUC) values for predicting high myopia at 5 and 10 years were 0.858 and 0.745, respectively. Furthermore, calibration curves demonstrated excellent agreement between the predicted and observed outcomes throughout the follow-up period. In external validation, the model achieved a C-index of 0.825, 5-year AUC of 0.833, and 10-year AUC of 0.713. CONCLUSIONS: Our analysis established that initial postoperative refraction <+0.75D, and an elevated IOL/AL ratio are key determinants of high myopia risk following surgery. Shorter preoperative axial length was associated with a greater magnitude of postoperative myopic shift. This predictive framework provides clinicians with a practical tool to optimize preoperative IOL selection and identify high-risk infants who require vigilant myopia prevention and balanced amblyopia management.

Humans↗

PubMed2025

Intraocular pressure is a promising target for myopia control.

BACKGROUND: Myopia presents a noteworthy global health concern, urging exploration of innovative treatments. The role of intraocular pressure (IOP) in regulating the progression of myopia has been controversial. METHODS: To investigate the impact of reducing IOP to varying extents on myopia progression, three groups receiving distinct IOP-lowering medications (Brinzolamide, Latanoprost, and a combination of Brinzolamide and Latanoprost) were designed in a form-deprived myopic guinea pig model. Additionally, proteomics analyses were conducted to identify differentially expressed proteins in the sclera. RESULTS: Based on 24-h and 4-week IOP monitoring, the group receiving both Brinzolamide and Latanoprost exhibited the greatest magnitude of IOP reduction and the most significant inhibition of axial length (AL) growth. Moreover, the administration of IOP-lowering medications increased choroidal thickness and induced alterations in the structure of scleral collagen fibrils. Notably, scleral proteomics revealed remodeling processes associated with key mechanisms, including proteolysis, fibrinolysis, and metal ion binding. CONCLUSIONS: Our findings highlight that pressure-dependent scleral remodeling contributes to the deceleration of AL elongation. These results underscore the efficacy of IOP reduction in mitigating the progression of myopia, providing a promising alternative strategy for myopia management.

Myopia↗

PubMed2026

Biological mechanisms of atropine in myopia control (Review).

Myopia is now recognized as a progressive, potentially sight‑threatening disease rather than just a refractive error, with its prevalence rising rapidly worldwide due to its high occurrence, major vision losses and huge public health cost. The World Health Organization estimates that 2.6 billion individuals in the world were myopic in 2020 this figure is projected to increase to 3.364 billion by 2030. Although myopia may be better controlled in its early stages, it may not be completely reversed at this time. Of all of the methods for controlling myopia, atropine, a muscarinic receptor antagonist, remains an effective pharmacological option for slowing myopia progression in children. However, the mechanisms of action of atropine remain to be fully elucidated. This review provided a systematic review for myopia epidemiology, pathogenesis, the effects and side effects, as well as up‑to‑date possible mechanisms, in the hope of facilitating that researchers in this field elucidate its underlying mechanisms so that clinical ophthalmologists may be able to better control this disease.

Humans↗

PubMed2026

Increased PRSS56 expression is a causal factor and therapeutic target for human axial high myopia.

High myopia (HM), characterized by significant ocular axial length elongation, affects hundreds of millions of people and is often inherited, particularly in cases that develop during childhood or adolescence. Although numerous myopia loci (MYP) have been identified, most causative genes remain undefined. Here, we analyzed two large HM pedigrees and refined the critical region through haplotype linkage analysis to a 3.9-Mb interval on 2q37.1, which was previously reported as MYP12 with an unknown pathogenic gene. Whole-genome sequencing identified the noncoding promoter variants c.-187G>T and c.-187G>C in PRSS56, encoding a trypsin-like serine protease, which exclusively co-segregated with all affected members in both pedigrees. Compared with matched controls, increased PRSS56 expression was observed in both patient-derived iPSCs carrying c.-187G>T and knock-in mice (c.-155G>T, corresponding to human c.-187G>T) that faithfully recapitulate myopia phenotypes. Noncoding PRSS56 variants promote self-expression via enhanced binding to the transcription factor EGR1, as confirmed by dual-luciferase assays. Notably, we demonstrated that higher PRSS56 levels directly increase ocular axial length in a dose- and activity-dependent manner in multiple transgenic mouse models. Guinea pig myopia models consistently exhibited high Prss56 expression, and short-wave light exposure reduced Prss56 mRNA levels and attenuated further axial elongation. Mechanistically, higher PRSS56 expression was associated with reduced abundance of myosin-4 in the sclera and with molecular signatures of scleral remodeling, which were in turn correlated with axial elongation. In conclusion, our findings provide strong genetic and functional evidence for the pathogenic role of noncoding PRSS56 variants in HM and highlight PRSS56 as a promising therapeutic target for juvenile HM.

Humans↗

PubMed2026

Association of long-term exposure to ambient air pollution and myopia in Chinese children.

Ambient air pollution is recognized as a major global health concern, but evidence on its association with childhood myopia remains limited, particularly under multi-pollutant exposure conditions. A school-based study was conducted in Tianjin, China, including 212,566 students in grades 4-6. The 3-yr mean concentrations of particulate matter with aerodynamic diameter ≤ 2.5 μm (PM2.5), its major components (sulfate (SO42-), nitrate (NO3-), ammonium (NH4+), organic matter (OM), and black carbon (BC)), and ozone (O3) were estimated using machine-learning exposure models and linked to school locations. Restricted cubic splines and quartile-based modified Poisson models were used to assess single-pollutant exposure-response relationships, and quantile-based g-computation was applied to estimate joint pollutant associations. In single-pollutant models, the highest quartile of SO42- was associated with higher myopia prevalence compared with the lowest quartile (PR = 1.10; 95% CI, 1.07-1.13). O3 showed weaker and non-monotonic positive patterns (Q4 vs Q1: PR = 1.03; 95% CI, 1.00-1.05). In mixture analyses, a one-quartile increase in joint exposure was associated with higher myopia prevalence (PR = 1.017; 95% CI, 1.007-1.027). Sensitivity analyses generally supported the direction of the main findings. These findings suggest that long-term exposure to specific ambient air pollutants may be associated with myopia in school-aged children.

Chemical components↗

PubMed2026

A validated sensitive LC-MS/MS method and its application in elucidating the unique ocular pharmacokinetic profile of 0.01% atropine underpinning its clinical utility for myopia.

A sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated to quantify atropine in ten rabbit ocular tissues enabling systematic characterization of the ocular pharmacokinetic profile of 0.01% atropine sulfate eye drops after a single topical administration. The method demonstrated excellent linearity (coefficient of determination, R2 ≥ 0.9908) across all matrices, with lower limits of quantification (LLOQ) of 0.05 ng/mL for most tissues and 0.10 ng/mL for retina and lens; intra- and inter-day accuracy, precision, matrix effects, extraction recoveries, and stability all met the acceptance criteria. Following a single bilateral topical dose (50 μL/eye) in New Zealand White rabbits, atropine distributed rapidly into all 12 ocular compartments (the sclera further divided into three anatomical regions) with marked heterogeneity-the highest exposures were found in conjunctiva and cornea, a distinct anterior-to-posterior concentration gradient was observed in the sclera, sustained retention was noted in the retina (mean residence time from zero to the last measurable time point, MRT0-t 3.30 h), while aqueous and vitreous humor eliminated rapidly (elimination half-life, t₁/₂ < 0.7 h), and all tissues except aqueous humor followed a two-compartment model. This validated method and the comprehensive pharmacokinetic data reveal that topically applied 0.01% atropine achieves sustained exposure in key myopia-regulating tissues (retina, choroid, posterior sclera) with low exposure in side-effect target tissues (iris, ciliary body, lens).

Animals↗

PubMed2026

CHST5 gene mutations contribute to high myopia by disrupting collagen fiber organization.

High myopia (HM) is a leading cause of irreversible vision loss in working-age adults. Its pathogenesis is characterized by alterations in the microstructure and composition of collagen fibers, and genetic factors make a substantial contribution. In this study, we identify carbohydrate sulfotransferase 5 (CHST5) as a candidate gene for HM in humans and mice, with its mutations disrupting collagen fiber organization. The c.444C>A (p.S148R) variant in CHST5, a gene critical for sulfating corneal keratan sulfate (KS), completely co-segregates with HM in a Chinese family. Screening of CHST5 variants in 320 HM patients identifies two additional ones. We further find that Chst5 is expressed primarily in the cornea and sclera of mouse ocular tissues, and that the mutant protein CHST5S148R loses its Golgi localization. Homozygous mutant Chst5S126R mice exhibit HM phenotypes, including myopic refractive error (RE), significantly thinner sclera and cornea, notable microstructural changes in scleral and corneal collagen fibers, and shorter corneal KS chains. Our findings suggest that CHST5 NM_024533.5 c.444C>A (p.S148R) causes loss of proper protein localization, likely impairing its sulfotransferase function. This defect disrupts the organization of corneal and scleral collagen fibers and ultimately contributes to the development and progression of HM.

CHST5↗

PubMed2026

Efficacy, tolerability, and threshold effect of atropine eye drops for myopia control: A systematic review and dose-response meta-analysis.

Atropine is an emerging therapy for myopia, yet the optimal concentration for prescription remains uncertain. We searched PubMed, Embase, Web of Science, Cochrane Library, World Health Organization International Clinical Trials, and ClinicalTrials.gov registry platforms. We included the randomized clinical trials (RCTs) that compared any dose of atropine against a placebo in myopic children. Among 3566 studies assessed, we identified 33 eligible RCTs involving 6301 children aged 4-18 years, with 10 different concentrations and a mean follow-up time of 19.5 ± 12.3 months. A nonlinear relationship was observed between atropine dosage and treatment efficacy (P < 0.001). Compared to placebo groups, the mean differences in reducing annual spherical equivalent refraction progression for atropine concentrations of 0.01%, 0.02%, 0.03%, 0.04%, and 0.05% were 0.21 diopters (D) (95% CI, 0.13-0.28), 0.35 D (95% CI, 0.23-0.46), 0.42 D (95% CI, 0.28-0.56), 0.45 D (95% CI, 0.30-0.60), and 0.46 D (95% CI, 0.32-0.61) respectively For higher concentrations, the estimates were 0.49 D (95% CI, 0.34-0.63) for 0.1% and 0.99 D (95% CI, 0.66-1.31) for 1%, although these were based on fewer and smaller trials. Higher doses of atropine were associated with decreased amplitude of accommodation (P = 0.02), increased pupil diameters (P = 0.01) and a higher frequency of photophobia (P = 0.02). Our findings suggest that the increase in treatment efficacy with higher concentrations may plateau beyond a certain range, and that the current practice of increasing atropine concentrations for children who show inadequate responses to lower doses should be confined to a specific concentration range. This analysis is limited by the number, design heterogeneity, and sample sizes of available trials for higher concentrations, and by the frequent lack of pre-intervention refractive history in included studies. Therefore, estimates-particularly for doses exceeding 0.1%-should be interpreted with caution.

Humans↗

PubMed2026

Differences in circadian rhythm changes between myopic and non-myopic college students over 2 years.

This study aimed to characterize and compare the differences in circadian rhythm changes during 2 years between college students with myopia and non-myopia based on a longitudinal cohort study. Wake-up time and bedtime were obtained through a self-administered questionnaire. Chronotype was assessed using the reduced Morningness-Eveningness Questionnaire (rMEQ). Circadian rhythm timing was determined by dim-light melatonin onset (DLMO), measured through hourly saliva collection from 21:00 to 01:00. A total of 450 college students (146 [32.4%] males) with a mean age of 18.65 ± 1.05 years were included, of whom 353 (78.4%) students had myopia. Compared with non-myopic individuals, myopic students slept later, woke up earlier, and exhibited lower rMEQ scores at baseline. Over the 2-year follow-up, both groups showed significantly earlier bedtimes, later wake-up times, and higher rMEQ scores. Only myopic students demonstrated a 45-minute delay in DLMO after the 2-year follow-up. After adjusting for potential confounders, linear mixed-effects models showed that myopic individuals had later bedtimes and earlier wake-up times. These findings indicate significant circadian rhythm changes in individuals with myopia, suggesting the potential of targeted sleep rhythm interventions on preventing myopia.

Myopia↗

PubMed2025

Causal association between different types of ametropia and risk of diabetic retinopathy: a two-sample Mendelian randomization study.

OBJECTIVE: To investigate the causal link between ametropia and diabetic retinopathy, as well as to offer genetic support for the association between these two conditions. METHODS: This study employed a methodology involving the utilisation of genome-wide association studies data that are publicly accessible. Specifically, single nucleotide polymorphisms (SNPs) that exhibit a strong association with ametropia were employed as instrumental variables, and a two-sample Mendelian randomization (MR) approach was employed to examine the causal relationship between different types of ametropia and diabetic retinopathy. The main findings were derived from the utilisation of inverse variance weighted (IVW), while supplementary results were obtained through the utilisation of MR Egger, weighted median, simple mode and weighted mode. Additionally, a sensitivity analysis was conducted using the 'leave-one-out' method. Cochran's Q statistics were also used to quantify the heterogeneity of SNPs. RESULTS: 38 SNPs were finally included. The results of the IVW analysis indicate that myopia may exert an inhibitory effect on the development of diabetic retinopathy (OR=0.596, 95% CI (0.371, 0.957), p<0.05). Conversely, hypermetropia (OR=8.882, 95% CI (0.389×10-3, 2.06×105), p>0.05) and astigmatism (OR=1.004, 95% CI (0.888, 1.135), p>0.05) do not exhibit a causal relationship with the risk of diabetic retinopathy. CONCLUSION: This two-sample Mendelian randomization study provides evidence that myopia may impede diabetic retinopathy occurrence, while hypermetropia and astigmatism show no significant causal effects. However, our analysis treats refractive errors as independent entities, which may not reflect their clinical interdependence. Further investigations are warranted to elucidate myopia's protective mechanisms.

Humans↗

PubMed2026

Variance Polygenic Scores (vPGS) as a Tool for Studying Gene-Environment Interactions Associated With Refractive Error.

PURPOSE: Conventional polygenic scores predict an individual's phenotype based on their genetics. By contrast, variance polygenic scores (vPGS) quantify genetic predisposition to phenotypic variance. We tested the hypothesis that a vPGS for refractive error can identify individuals with increased susceptibility to environmental risk factors for myopia. METHODS: Six vPGS construction strategies were evaluated in UK Biobank participants: three variance heterogeneity genome-wide association study (vGWAS) methods and two reweighting schemes. vPGS performance was assessed using two metrics: (i) "Diff"-difference in phenotypic variance in vPGS decile ten versus one; (ii) Spearman correlation of phenotypic variance versus vPGS decile. The optimal vPGS was used to test for vPGS × time spent reading or vPGS × time spent outdoors interactions in children aged 15 years (ALSPAC cohort; n = 3471). RESULTS: Of the vGWAS methods, conditional quantile regression outperformed SCAMPI and Levene's Test. Of the re-weighting schemes, LDpred2 outperformed pruning and thresholding. In an independent sample of UK Biobank participants (n = 19,470), the top-performing vPGS successfully stratified individuals into groups with increasing variance in refractive error, even after adjusting for a conventional PGS (Diff: 2.55, 95% confidence interval [CI], 1.64-3.47; Spearman correlation = 0.87; 95% CI, 0.43-0.93). However, in ALSPAC participants, there was minimal support for vPGS interactions with time reading (P = 0.80) or time outdoors (P = 0.89). CONCLUSIONS: A novel vPGS successfully stratified individuals into groups with relatively high or low genetic susceptibility to refractive error variance. However, the vPGS could not identify individuals at enhanced risk from lifestyle risk factors for myopia.

Humans↗

PubMed2026

EGFLAM Pathogenic Variants and Congenital Stationary Night Blindness.

IMPORTANCE: Congenital stationary night blindness (CSNB) is a clinically and genetically heterogeneous inherited retinal disorder (IRD), and in many complete CSNB (cCSNB) cases, the underlying genetic cause remains unknown. Uncovering the genetic defects of IRDs helps to refine diagnostic methods and supports the development of specific therapeutic approaches. OBJECTIVE: To describe the phenotype and the underlying gene defect in patients with cCSNB from 2 unrelated families. DESIGN, SETTING AND PARTICIPANTS: This retrospective case series was conducted from January 2023 to July 2025. Data for 3 patients from cohorts of genetically unsolved IRD cases in France (n = 140 for CSNB) and the Netherlands (n = 2730 for IRD) were analyzed clinically and genetically. EXPOSURES: Complete ocular examination, including multimodal retinal imaging and full-field electroretinography (ffERG) incorporating the International Society for Clinical Electrophysiology of Vision standards and multimodal retinal imaging, were performed. Gene defects were identified by genome sequencing (GS) and exome sequencing (ES). MAIN OUTCOMES AND MEASURES: The main outcome was a gene defect, EGFLAM, underlying cCSNB. Measures included phenotyping, GS, ES, Sanger sequencing, and cosegregation analysis. RESULTS: The series included 3 patients from 2 unrelated families of Moroccan ancestry showing high myopia, reduced visual acuity, and night blindness. Retinal imaging depicted myopic changes. ffERG revealed electronegative Schubert-Bornschein configuration in keeping with cCSNB with ON-bipolar cell dysfunction. Patients were lacking pathogenic variants in known genes implicated in IRDs, including CSNB. Two different homozygous pathogenic variants, c.1563_1566del, p.(Val522Glufs*18) and c.1795C>T, p.(Arg599*) in EGFLAM were identified by ES and GS. The corresponding protein is localized in the outer plexiform layer and important for ON-bipolar cell signaling in the retina. CONCLUSION AND RELEVANCE: This case series reports on a gene defect in EGFLAM implicated in human cCSNB. Clinicians should be aware about this association and consider including EGFLAM in diagnostic gene panels for IRDs. This discovery may lead to faster and more accurate diagnosis of cCSNB and genetic counseling, as well as a pathway for developing therapies.

Adolescent↗

PubMed2025

Co-morbid monogenic disorders at chromosome region 1q2: LMNA- and FLG-related disorders in a patient referred for assessment of joint hypermobility.

The phenotypic similarities and genetic heterogeneity occurring in diverse forms of Ehlers Danlos Syndrome (EDS) subtypes and many heritable connective tissue disorders can pose a diagnostic challenge. In the wake of the growing applications of next-generation sequencing technologies including exome and genome sequencing, opportunities for achieving definitive genetic diagnosis are increasingly arising. We present a 46-year-old man with joint laxity, recurrent joint subluxations, pelvic floor dysfunction, and postural orthostatic tachycardia syndrome (POTS), who was referred for EDS assessment. His medical history included morbid obesity requiring gastric bypass surgery, hearing loss, asthma, retinopathy, myopia, atrial septal defect, narcolepsy with cataplexy, polyneuropathy, folliculitis, lichen simplex chronicus, atopic dermatitis, and hypogonadism. His family history was significant for multiple first- and second-degree relatives who died from cardiac diseases including cases of childhood deaths. Physical examination showed joint laxity with Beighton score of 3/9, bilateral pes planus, hearing loss and macrocephaly. Exome sequencing revealed heterozygous variants LMNA c.1262 T > C p.L421P [classified as likely pathogenic], FLG c.2282_2285del p. S761Cfs*36 [classified as pathogenic], and FLG c.1501 C > T p. R501* [classified as pathogenic]. Mitochondria sequencing revealed a variant of uncertain significance (VUS), MT-ND2 m.5047 T > C p.V193A that is present at 9% heteroplasmy in blood. These findings show co-occurrence of pathogenic sequence variants in neighboring genes located in chromosome 1q2 region [LMNA and FLG] in a patient with features of hereditary connective tissue disorders. Our study highlights the capability of exome sequencing in achieving some actionable diagnosis in cases of co-morbid genetic disorders with overlapping and non-specific symptoms.

Humans↗

PubMed2025

Identification of IDH3G, encoding the gamma subunit of mitochondrial isocitrate dehydrogenase, as a novel candidate gene for X-linked retinitis pigmentosa.

PURPOSE: Retinitis pigmentosa (RP) is a genetically heterogeneous group of retinal degenerative disorders characterized by the loss of rod and cone photoreceptors, leading to visual impairment and blindness. To date, to our knowledge, X-linked RP has been associated with variants in 3 genes (RPGR, RP2, and OFD1), whereas genetic defects at 3 loci (RP6, RP24, and RP34) are yet unidentified. The aim of this study was to identify a novel candidate gene underlying X-linked RP. METHODS: Participants were identified from cohorts of genetically unsolved male individuals affected by RP, who underwent genome sequencing, exome sequencing, or candidate gene screening via direct Sanger sequencing at 3 referral centers. Specifically, 2 probands were identified at the National Reference Centre for Rare Retinal Diseases (Paris, France), 2 at the Massachusetts Eye and Ear Hospital (Boston, MA), and 1 at the National Reference Centre for Inherited Sensory Diseases (Montpellier, France). The pathogenicity of the identified variants was assessed using bioinformatic predictions, protein expression analyses, and mitochondrial function assays. RESULTS: We identified 4 rare single-nucleotide variants in IDH3G (HGNC:5386), located at the RP34 locus on the X chromosome, and a complete gene deletion, in 5 unrelated male individuals affected with nonsyndromic RP. The variants segregated with the phenotype in all available family members. In all cases, the disease severity was intermediate. None had high myopia. IDH3G encodes the γ subunit of mitochondrial isocitrate dehydrogenase (IDH3), an enzyme involved in the citric acid cycle, which is expressed in the inner segments of photoreceptors. Variants in IDH3A and IDH3B, encoding the other subunits of IDH3, have already been associated with nonsyndromic autosomal recessive RP. Bioinformatic predictions and functional assays support a pathogenic role for the variants identified in this study, possibly through partial loss of enzymatic activity and mitochondrial function. CONCLUSION: Our findings suggest that variants in IDH3G are a novel cause of X-linked RP.

Humans↗

PubMed2026

Identification of Two Novel Compound Heterozygous ADAMTS17 Variants Associated With Weill-Marchesani Syndrome 4.

PURPOSE: Weill-Marchesani syndrome 4 (WMS4) is frequently underdiagnosed when standard exome sequencing fails to detect noncoding pathogenic variants. We aimed to identify the genetic cause in a patient with suspected WMS4 and to characterize the splicing-altering mechanism of a deep intronic variant in ADAMTS17. MATERIALS AND METHODS: Whole-exome sequencing combined with whole-genome sequencing was conducted in the proband, who presented with ocular and skeletal manifestations of WMS4. A minigene splicing assay was applied to verify the splicing abnormality caused by the deep intronic variant. RESULTS: The patient showed high myopia, brachydactyly, accelerated growth velocity, and advanced bone age. Two novel compound heterozygous variants in ADAMTS17, c.1655G>A and c.450+38C>A, were identified. The deep intronic variant c.450+38C>A was confirmed by minigene assay to disrupt normal pre-messenger RNA splicing by inducing retention of a 35-base pair intronic segment, leading to a frameshift and premature termination (p.G152Lfs*23). CONCLUSIONS: This study broadens the mutational spectrum of ADAMTS17. Whole-genome sequencing combined with functional splicing validation is essential for resolving molecularly undiagnosed cases of WMS4, particularly when deep intronic variants are suspected, and supports clinical genetic testing and genetic counseling of hereditary connective tissue disorders.

ADAMTS17↗