So far, linkage-based approaches have resulted in the discovery of eight causative genes for monogenic POAG namely, MYOC (GLC1A), OPTN (GLC1E), ASB10 (GLC1F), WDR36 (GLC1G), NTF4 (GLC1O), TBK1 (GLC1P), CYP1B1 (GLC3A), and LTBP2 (GLC3D). Here, NTF4 is linked to open-angle glaucoma.