Individuals homozygous for the rs4656461 TMCO1 risk allele have been found to develop glaucoma 4–5 years earlier than non-carriers in families with a strong family history (Sharma et al., 2012); however, none of the reported TMCO1-associated risk alleles are located in coding regions of the TMCO1 gene. Here, TMCO1 is linked to glaucoma.