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Nearsightedness (myopia) is a global health problem of staggering proportions that has driven the hunt for environmental and genetic risk factors in hopes of gaining insight into the underlying mechanism and providing new avenues of intervention. Myopia is the dominant risk factor for leading causes of blindness, including myopic maculopathy and retinal detachment. The fundamental defect in myopia—an excessively elongated eyeball—causes blurry distance vision that is correctable with lenses or surgery, but the risk of blindness remains. Haplotypes of the long-wavelength and middle-wavelength cone opsin genes (OPN1LW and OPN1MW, respectively) that exhibit profound exon-3 skipping during pre-messenger RNA splicing are associated with high myopia. Cone photoreceptors expressing these haplotypes are nearly devoid of photopigment. Conversely, cones in the same retina that express non-skipping haplotypes are relatively full of photopigment. We hypothesized that abnormal contrast signals arising from adjacent cones differing in photopigment content stimulate axial elongation, and spectacles that reduce contrast may significantly slow myopia progression. We tested for an association between spherical equivalent refraction and OPN1LW haplotype in males of European ancestry as determined by long-distance PCR and Sanger sequencing and identified OPN1LW exon 3 haplotypes that increase the risk of common myopia. We also evaluated the effects of contrast-reducing spectacles lenses on myopia progression in children. The work presented here provides new insight into the cause and prevention of myopia progression.

Background Among sex chromosome aneuploidies, 48, XXYY syndrome is a rare variant. This condition is marked by the existence of an additional X and Y chromosome in males, leading to a diverse range of physical, neurocognitive, behavioral, and psychological manifestations. Typical characteristics include a tall stature and infertility. Other phenotypes include congenital heart defects, skeletal anomalies, tremors, obesity, as well as the potential for type 2 diabetes and/or peripheral vascular disease. Case presentation A 6-year-old boy, who had been experiencing progressive vision deterioration in both eyes for the past two years, presented with a history of poor vision, delayed motor skills. The patient was diagnosed with micropenis in the pediatric outpatient clinic. Sparse hair, an unusually tall stature and craniofacial dysmorphology characterized by ocular hypertelorism, depressed nasal bridge, and epicanthic folds were observed. Comprehensive ophthalmic examination revealed high myopia and grade 3 macular hypoplasia. Diagnostic investigations including karyotype analysis and whole-exome sequencing identified an anomalous male karyotype comprising two X and two Y chromosomes, confirming a diagnosis of 48, XXYY syndrome. Conclusions This study underscores the rare association of high myopia and grade 3 macular dysplasia with 48, XXYY syndrome. To our knowledge, this case marks the first recorded instance of macular dysplasia in a patient with 48, XXYY syndrome. This novel finding enhances our understanding of this syndrome’s phenotypic variability.

AimsTo investigate the association of the paired box gene 6 (PAX6) with different severities of myopia.MethodsA total of four haplotype-tagging single-nucleotide polymorphisms (SNPs; rs2071754, rs3026354, rs3026390 and rs628224) and two previously reported SNPs (rs644242 and rs662702) in the PAX6 gene were analysed in a Hong Kong Chinese cohort of 1288 myopia subjects (including 252 extreme myopia, 277 high myopia, 393 moderate myopia and 366 mild myopia) and 791 no myopia controls. Allelic association analyses were performed for individual SNPs in different subgroups of myopia and in combined myopia, followed by a meta-analysis of our current data with reported data on PAX6 in myopia.ResultsThe association of tagging SNPs rs2071754 and rs644242 with extreme myopia could not withstand multiple correction (rs2071754: OR=1.25, P value=0.031; rs644242: OR=1.33, P value=0.032). In the meta-analysis, rs644242 showed an enhanced, significant association with extreme myopia (OR=1.27, 95% CI 1.10 to 1.46, P value=0.001; I2=0%). In contrast, there was no significant association between the PAX6SNPs and high, moderate or mild myopia. No linear correlation was found between the PAX6SNPs and axial length.ConclusionThis study provides additional evidence suggesting that the PAX6 SNP rs644242 is associated with extreme myopia but not lower grade myopia. Thus, PAX6 may be implicated in the development or progression into severe myopia. Further longitudinal studies are warranted.

PurposeMyopia, especially high myopia (HM), represents a widespread visual impairment with a globally escalating prevalence. This study aimed to elucidate the genetic foundations associated with early-onset HM (eoHM) while delineating the genetic landscape specific to Shaanxi province, China.MethodsA comprehensive analysis of whole-exome sequencing was conducted involving 26 familial trios displaying eoHM. An exacting filtration protocol identified potential candidate mutations within acknowledged myopia-related genes and susceptibility loci. Subsequently, computational methodologies were employed for functional annotations and pathogenicity assessments.ResultsOur investigation identified 7 genes and 10 variants associated with HM across 7 families, including a novel mutation in the ARR3 gene (c.139C>T, p.Arg47*) and two mutations in the P3H2 gene (c.1865T>C, p.Phe622Ser and c.212T>C, p.Leu71Pro). Pathogenic mutations were found in syndromic myopia genes, notably encompassing VPS13B, TRPM1, RPGR, NYX and RP2. Additionally, a thorough comparison of previously reported causative genes of syndromic myopia and myopia risk genes with the negative sequencing results pinpointed various types of mutations within risk genes.ConclusionsThis investigation into eoHM within Shaanxi province adds to the current understanding of myopic genetic factors. Our results warrant further functional validation and ocular examinations, yet they provide foundational insights for future genetic research and therapeutic innovations in HM.

Refractive errors, in particular myopia, are a leading cause of morbidity and disability worldwide. Genetic investigation can improve understanding of the molecular mechanisms that underlie abnormal eye development and impaired vision. We conducted a meta-analysis of genome-wide association studies (GWAS) that involved 542,934 European participants and identified 336 novel genetic loci associated with refractive error. Collectively, all associated genetic variants explain 18.4% of heritability and improve the accuracy of myopia prediction (area under the curve (AUC) = 0.75). Our results suggest that refractive error is genetically heterogeneous, driven by genes that participate in the development of every anatomical component of the eye. In addition, our analyses suggest that genetic factors controlling circadian rhythm and pigmentation are also involved in the development of myopia and refractive error. These results may enable the prediction of refractive error and the development of personalized myopia prevention strategies in the future. Meta-analysis of genome-wide association studies of 542,934 individuals identifies 336 novel loci associated with refractive error and implicates eye development, circadian rhythm and pigmentation pathways in controlling myopia.

Cohen syndrome (CS) is a rare autosomal recessive condition caused by mutations and/or large rearrangements in the VPS13B gene. CS clinical features, including developmental delay, the typical facial gestalt, chorioretinal dystrophy (CRD) and neutropenia, are well described. CS diagnosis is generally raised after school age, when visual disturbances lead to CRD diagnosis and to VPS13B gene testing. This relatively late diagnosis precludes accurate genetic counselling. The aim of this study was to analyse the evolution of CS facial features in the early period of life, particularly before school age (6 years), to find clues for an earlier diagnosis. Photographs of 17 patients with molecularly confirmed CS were analysed, from birth to preschool age. By comparing their facial phenotype when growing, we show that there are no special facial characteristics before 1 year. However, between 2 and 6 years, CS children already share common facial features such as a short neck, a square face with micrognathia and full cheeks, a hypotonic facial appearance, epicanthic folds, long ears with an everted upper part of the auricle and/or a prominent lobe, a relatively short philtrum, a small and open mouth with downturned corners, a thick lower lip and abnormal eye shapes. These early transient facial features evolve to typical CS facial features with aging. These observations emphasize the importance of ophthalmological tests and neutrophil count in children in preschool age presenting with developmental delay, hypotonia and the facial features we described here, for an earlier CS diagnosis.

Central corneal thickness (CCT) is a highly heritable trait associated with complex eye diseases such as keratoconus and glaucoma. We perform a genome-wide association meta-analysis of CCT and identify 19 novel regions. In addition to adding support for known connective tissue-related pathways, pathway analyses uncover previously unreported gene sets. Remarkably, >20% of the CCT-loci are near or within Mendelian disorder genes. These included FBN1 , ADAMTS2 and TGFB2 which associate with connective tissue disorders (Marfan, Ehlers-Danlos and Loeys-Dietz syndromes), and the LUM-DCN-KERA gene complex involved in myopia, corneal dystrophies and cornea plana. Using index CCT-increasing variants, we find a significant inverse correlation in effect sizes between CCT and keratoconus ( r  = −0.62, P  = 5.30 × 10 −5 ) but not between CCT and primary open-angle glaucoma ( r  = −0.17, P  = 0.2). Our findings provide evidence for shared genetic influences between CCT and keratoconus, and implicate candidate genes acting in collagen and extracellular matrix regulation. Reduced central corneal thickness (CCT) is observed in common eye diseases as well as in rare Mendelian disorders. Here, in a cross-ancestry GWAS, the authors identify 19 novel genetic loci associated with CCT, a subset of which is involved in rare corneal or connective tissue disorders.

Refractive errors, including myopia, are the most frequent eye disorders worldwide and an increasingly common cause of blindness. This genome-wide association meta-analysis in 160,420 participants and replication in 95,505 participants increased the number of established independent signals from 37 to 161 and showed high genetic correlation between Europeans and Asians (>0.78). Expression experiments and comprehensive in silico analyses identified retinal cell physiology and light processing as prominent mechanisms, and also identified functional contributions to refractive-error development in all cell types of the neurosensory retina, retinal pigment epithelium, vascular endothelium and extracellular matrix. Newly identified genes implicate novel mechanisms such as rod-and-cone bipolar synaptic neurotransmission, anterior-segment morphology and angiogenesis. Thirty-one loci resided in or near regions transcribing small RNAs, thus suggesting a role for post-transcriptional regulation. Our results support the notion that refractive errors are caused by a light-dependent retina-to-sclera signaling cascade and delineate potential pathobiological molecular drivers. Transancestral GWAS meta-analysis in 160,420 individuals identifies 139 loci associated with refractive error, including myopia. Newly identified genes implicate pathways involved in eye growth and light signaling cascades.

Keratoconus (KC) is the most common cornea ectatic disorder. It is characterized by a cone-shaped thin cornea leading to myopia, irregular astigmatism, and vision impairment. It affects all ethnic groups and both genders. Both environmental and genetic factors may contribute to its pathogenesis. This review is to summarize the current research development in KC epidemiology and genetic etiology. Environmental factors include but are not limited to eye rubbing, atopy, sun exposure, and geography. Genetic discoveries have been reviewed with evidence from family-based linkage analysis and fine mapping in linkage region, genome-wide association studies, and candidate genes analyses. A number of genes have been discovered at a relatively rapid pace. The detailed molecular mechanism underlying KC pathogenesis will significantly advance our understanding of KC and promote the development of potential therapies.

Caroline Klaver and colleagues report a meta-analysis for refractive error and myopia, including 37,382 individuals from 27 European studies and 8,376 individuals from 5 Asian studies, as part of the Consortium for Refractive Error and Myopia (CREAM). Refractive error is the most common eye disorder worldwide and is a prominent cause of blindness. Myopia affects over 30% of Western populations and up to 80% of Asians. The CREAM consortium conducted genome-wide meta-analyses, including 37,382 individuals from 27 studies of European ancestry and 8,376 from 5 Asian cohorts. We identified 16 new loci for refractive error in individuals of European ancestry, of which 8 were shared with Asians. Combined analysis identified 8 additional associated loci. The new loci include candidate genes with functions in neurotransmission ( GRIA4 ), ion transport ( KCNQ5 ), retinoic acid metabolism ( RDH5 ), extracellular matrix remodeling ( LAMA2 and BMP2 ) and eye development ( SIX6 and PRSS56 ). We also confirmed previously reported associations with GJD2 and RASGRF1 . Risk score analysis using associated SNPs showed a tenfold increased risk of myopia for individuals carrying the highest genetic load. Our results, based on a large meta-analysis across independent multiancestry studies, considerably advance understanding of the mechanisms involved in refractive error and myopia.