GRK4 and hypertensive disorder: The GRK4 locus on human chromosome 4p16.3 is linked to essential hypertension and salt sensitivity.79, 80, 81, 82, 83, 84, 85 Three missense SNPs ( ie, 65R>L, 142A>V, and 486A>V) in the coding region of GRK4γ are associated with increased blood pressure.