OPTN and glaucoma: Some inherited forms of primary open-angle glaucoma (Allingham et al., 2009) have been reported to be associated with expression of a specific variant or mutation in different genes such as sine oculis-related homeobox 6 (SIX6) (Carnes et al., 2014) or OPTINEURIN (OPTN) (Rezaie et al., 2002).