Easy to measure and accurate biomarkers, reflecting cardiac SNS activity, which will potentially support the risk stratification and guide the clinical management of the complex HHF syndrome, are urgently needed; myocardial GRK2 might be one of them as it is upregulated in HF patients, causing dysfunctional β-adrenergic receptor signaling and myocardial GRK2 levels correlating with levels found in peripheral lymphocytes in HF patients. The gene discussed is GRK2; the disease is hydrops fetalis.