ATXN2 loss of function results in glaucoma-related features supporting a role for Ataxin-2 in primary open-angle glaucoma (POAG) pathogenesis

Abstract

Glaucoma is a leading cause of irreversible blindness worldwide. The most common form, primary open-angle glaucoma (POAG), is a genetically complex trait with high heritability. Genome-wide association studies have identified significant POAG and IOP association of a genomic region on chromosome 12 that includes ATXN2 as well as 7 other genes. Association of protein disrupting ATXN2 variants in the NEIGHBORHOOD case-control cohort and the UK Biobank suggests that ATXN2 is a key gene in this locus. To investigate functional effects, we utilized a zebrafish (Danio rerio) CRISPR/Cas9 edited atxn2-knockdown line to show that loss of atxn2 results in reduced eye size, diminished retinal ganglion cells (RGC), increased intraocular pressure (IOP), and impaired visual function in zebrafish. Complementation assays supported functional effects for 14 POAG-associated human ATXN2 missense variants. These results suggest a loss-of-function mechanism underlying a potential role for ATXN2 in POAG pathogenesis.

Keywords: ATXN2; Intraocular pressure; Loss-of-function; Missense variants; Primary open-angle glaucoma; Retinal ganglion cell; Visual motor response; Zebrafish.