mRNA and protein levels of Nox2 (Wedgwood et al., 2012) and Nox4 (Wedgwood et al., 2013) are elevated in PPHN lungs and PASMC, and these Nox subunits are regulated by HIF-1α (Diebold et al., 2010b). The gene discussed is CYBB; the disease is persistent fetal circulation syndrome.