Although, BMP9 protects against PAH in adult mice and rats (Long et al., 2015) and BMP type II receptor (BMPRII) dysfunction enhances lung inflammation (Kim et al., 2013; Talati et al., 2014; Soon et al., 2015), the role of this TGF-β family member in neonatal chronic lung disease is unknown. The gene discussed is BMPR2; the disease is chronic lung disease.