Genetically proxied GK activation was associated with reduced risk of CAD (OR 0.38 per 1% lower HbA1c, 95% CI 0.29–0.51, P = 8.77 × 10−11) and HF (OR 0.54 per 1% lower HbA1c, 95% CI 0.41–0.73, P = 3.55 × 10−5). Here, GK is linked to hydrops fetalis.