In the penis of SCD mice, the isoform of NADPH oxidase-2 (gp91phox, NOX2) is one of the primary sources responsible for increased oxidative stress, along with the uncoupled eNOS and xanthine oxidase (Bivalacqua et al., 2013; Silva et al., 2016b; Musicki et al., 2018). The gene discussed is CYBB; the disease is Schnyder corneal dystrophy.