Primary open angle glaucoma (POAG) is the most common subtype of glaucoma, which can be regarded as a group of diseases with characteristic optic neuropathy that causes a distinctive pattern of progressive visual field loss that could eventually lead to blindness [1]. Several genes known to cause POAG have been identified, such as myocilin (MYOC), optineurin (OPTN), WD repeat domain 36 (WDR36), and neurotrophin 4 (NTF4), though the exact mechanisms by which they are causal remains unclear [2-5]. Conflicting evidence for association has created uncertainty about the importance of OPTN and NTF4 in POAG [6,7] in the general population, though there is evidence that OPTN may be specific for normal tension glaucoma (NTG) [3]. These genes are rare causes of the disease, and are detected in families affected by glaucoma, and thus account for few (<10%) POAG cases in total [8]. Association studies detect more common causes of disease and, more recently, several replicated genes have been detected using this method either on a genome-wide scale or by candidate gene analysis. Examples are a variant near the caveolin 1 (CAV1)
