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). The gene discussed is TBK1; the disease is open-angle glaucoma.