ADRB1 and hydrops fetalis: In particular, for the ADRB1 Arg389Gly C > G variant, we have shown that homozygotes ADRB1-Arg389 in our HF cohort exhibit a better response to βAR-blocker treatment (HR, 0.52; P = 0.002) than Gly389 homozygotes (HR, 0.51; P = 0.05) (Fig. 2i), similar to the situation of Caucasians26.