In animal models of BPD, TGF‐β1 levels and collagen production are increased, collagen fibers are thickened, and lungs are stiff and noncompliant, similar to findings in infants with BPD (Kotecha, Wangoo, Silverman, & Shaw, 1996; Thibeault, Mabry, Ekekezie, & Truog, 2000; Thibeault, Mabry, Ekekezie, Zhang, & Truog, 2003). The gene discussed is TGFB1; the disease is bronchopulmonary dysplasia.