SIX1 and open-angle glaucoma: SNPs at SIX1/SIX6 loci were first reported to be strongly associated with an increased VCDR (Ramdas et al., 2010), and then were shown to be associated with POAG (Ramdas et al., 2011; Wiggs et al., 2012; Iglesias et al., 2014) as well.