At present, we do not know the mechanisms that leads to changes in the expression of β2-AR and GRK2 in PBMC from PR patients, and a similar decrease was found in PBMC from HF patients, which reverts after cardiac transplantation (Montó et al., 2015), confirming its relationship to the evolution of the pathology. The gene discussed is ADRB2; the disease is hydrops fetalis.