Functional Genomic Analysis of Glaucoma Pathogenesis Due to gmds Mutation in Zebrafish
Glaucoma, a major cause of irreversible blindness, is characterized by optic nerve damage and loss of retinal ganglion cells (RGC). SNPs in the GDP-MANNOSE 4,6-DEHYDRATASE (GMDS) gene have been linked to primary open-angle glaucoma (POAG) and treatment responses. The GMDS gene plays a critical role in fucosylation, a process essential for modifying glycoproteins and glycolipids, yet no mechanism for its role in glaucoma pathology has been described. Our study investigates the effects of gmds haploinsufficiency using a CRISPR/Cas9 induced mutation in zebrafish. RNA sequencing (RNAseq) analysis shows significant downregulation of stress response genes including those of the crystallin family, and increased expression of cell death genes in gmds heterozygous mutant eyes. These gene expression changes correlate with phenotypic alterations, including RGC layer thinning, RGC loss, and reduced optic nerve head width in adult gmds heterozygotes relative to wild type siblings. Our findings provide new insights into the role of GMDS in regulating eye function and suggests that GMDS may influence glaucoma risk by regulating the response to stress. This study provides a layer of functional evidence supporting the predictions made by previous GWAS findings, enhancing our understanding of the genetic basis of glaucoma. It highlights the potential of GMDS as a therapeutic target for mitigating glaucoma-related vision loss, opening new avenues for glaucoma research and treatment development. Overall design: To investigate transcriptome changes in gmds +/- heterozygous eyes when compared to Wild type silbings. Three Wild type samples (each sample consisting of two eyes from a fish)  and three gmds +/- siblings samples were analysed at two time points: 1 and 2 years of age.