Previous studies suggest that collagen and other extracellular matrix (ECM) components are primarily synthesized by cardiac fibroblasts,[60] while inflammatory cells promote collagen production by secreting cytokines (e.g., TGF‐β, TNF‐α, IL‐1β, IL‐6) and activating fibroblasts.[58] In DCM, myocardial collagen is mainly secreted by fibroblasts, with inflammatory cells facilitating fibroblast activation through paracrine signaling or intercellular interactions. The gene discussed is TGFB1; the disease is familial dilated cardiomyopathy.