GNB3 and Hypertension: FTO protective haplotypes H2: CTGGC and H4: CTGAC interacted with GNB3 protective haplotype Ha: TC to contribute to 1.5- and 2.0-fold lower hypertension susceptibility than the individual protective haplotypes of either gene alone (P = 0.003; P = 6.86E–05, respectively).