Furthermore, knockdown of TFRC by tail intravenous injection of AAV‐shR‐TFRC significantly decreased macrophages infiltration which was stained by the macrophage maker F4/80+ in the HF tissues (Figure 1E), and deteriorated heart function with decreased EF% and increased LVEDd measured by echocardiographic evaluation (Figure 1F,G). The gene discussed is TFRC; the disease is hydrops fetalis.