CPS1 and Hypertension: When using IV without the pleiotropic CPS1 locus, only a suggestive association between circulating level of glycine and SBP (− 0.79 ± 0.30 mmHg per 1-SD, P = 0.009) or risk of hypertension (0.98 [0.97–0.99] per 1-SD, P = 0.009) were observed, and there was no causal effect of circulating glycine on DBP (P > 0.05, Fig. 3).