This study demonstrates that the CASZ1 gene associated C-allele of rs11121615 has a significant, reproducible, association with CVD (CEAP C ≥ 2 meta-odds ratio 1.31, 95% CI 1.27–1.34, P = 1 × 10−98, PHet = 0.25), but not with non-varicose vein (CEAP C1, telangiectasia or reticular veins) forms of venous disease. Here, BLOC1S2 is linked to telangiectasis.