Whole-Exome Sequencing in a Cohort of High Myopia Patients in Northwest China.

High myopia (HM) is one of the leading causes of visual impairment worldwide. In order to expand the myopia gene spectrum in the Chinese population, we investigated genetic mutations in a cohort of 27 families with HM from Northwest China by using whole-exome sequencing (WES). Genetic variations were filtered using bioinformatics tools and cosegregation analysis. A total of 201 candidate mutations were detected, and 139 were cosegregated with the disease in the families. Multistep analysis revealed four missense variants in four unrelated families, including c.904C>T (p.R302C) in CSMD1, c.860G>A (p.R287H) in PARP8, c.G848A (p.G283D) in ADAMTSL1, and c.686A>G (p.H229R) in FNDC3B. These mutations were rare or absent in the Exome Aggregation Consortium (ExAC), 1000 Genomes Project, and Genome Aggregation Database (gnomAD), indicating that they are new candidate disease-causing genes. Our findings not only expand the myopia gene spectrum but also provide reference information for further genetic study of heritable HM.

Expanding the Phenotypic and Genotypic Landscape of Nonsyndromic High Myopia: A Cross-Sectional Study in 731 Chinese Patients.

Purpose: High myopia (HM) is defined as a refractive error worse than -6.00 diopter (D). This study aims to update the phenotypic and genotypic landscape of nonsyndromic HM and to establish a biological link between the phenotypic traits and genetic deficiencies. Methods: A cross-sectional study involving 731 participants varying in refractive error, axial length (AL), age, myopic retinopathy, and visual impairment. The phenotypic traits were analyzed by four ophthalmologists while mutational screening was performed in eight autosomal causative genes. Finally, we assessed the clinical relevance of identified mutations under the guidance of the American College of Medical Genetics and Genomics. Results: The relationship between refractive error and AL varied in four different age groups ranging from 3- to 85-years old. In adult groups older than 21 years, 1-mm increase in AL conferred 10.84% higher risk of pathologic retinopathy (Category ≥2) as well as 7.35% higher risk of low vision (best-corrected visual acuities <0.3) with P values < 0.001. The prevalence rates of pathologic retinopathy and low vision both showed a nonlinear positive correlation with age. Forty-five patients were confirmed to harbor pathogenic mutations, including 20 novel mutations. These mutations enriched the mutational pool of nonsyndromic HM to 1.5 times its previous size and enabled a statistically significant analysis of the genotype-phenotype correlation. Finally, SLC39A5, CCDC111, BSG, and P4HA2 were more relevant to eye elongation, while ZNF644, SCO2, and LEPREL1 appeared more relevant to refracting media. Conclusions: Our findings shed light on how multiple HM-related phenotypes are associated with each other and their link with gene variants.

Evaluating correlation between the ocular biometry and genetic variants of MYOC and ABCA1 with primary angle-closure glaucoma in a cohort from northern China.

AIM: To investigate whether the gene variants in MYOC and ABCA1 are associated with primary angle-closure glaucoma (PACG) and anterior chamber depth (ACD) and axial length (AL) in samples from northern China. METHODS: The present case-control association study consisted of 500 PACG patients and 720 unrelated controls. Each participant was genotyped for eleven single nucleotide polymorphisms (SNPs) in MYOC and ABCA1 genes (rs12076134, rs183532, rs235875 and rs235913 in MYOC, rs2422493, rs2487042, rs2472496, rs2472493, rs2487032, rs2472459 and rs2472519 near ABCA1) using an improved multiplex ligation detection reaction (iMLDR) technique. The genetic association analyses were performed by PLINK using a logistic regression model. The association between genotypes and ocular biometric parameters was performed by SPSS using generalized estimation equation. Bonferroni corrections were implemented and the statistical power was calculated by the Power and Sample Size Calculation. RESULTS: Two SNPs rs183532 and rs235875 as well as a haplotype TTC in MYOC were nominally associated with PACG despite the significance was lost after Bonferroni correction. No association was observed between ABCA1 and PACG, neither did the association between these variants and ACD as well as AL. CONCLUSION: The present study suggests MYOC and ABCA1 do not play a part in the pathogenesis of PACG as well as the regulation of ocular biometric parameters in a northern Chinese population. Further investigations with large sample size are needed to verify this consequence.