The diameter of the retinal microvasculature was associated with genes TEAD1, TSPAN10, GNB3, and OCA2. 39A recently published study43 on vascular density and fractal dimensions reported 7 and 13 single nucleotide polymorphisms (SNPs) associated with these traits respectively, including OCA2, MEF2C, and GNB3. Retinal vessel tortuosity has been associated with SNPs that map to the genes ACTN4 and COL4A2. 44Tortuosity of the vasculature was reported in the context of coronary artery disease (CAD)44 and connective tissue disease.45 The gene discussed is COL4A2; the disease is coronary artery disorder.