MAOA and hyperinsulinemic hypoglycemia, familial, 4: Studies using a mouse model of collagen VI deficiency, Col6a1−/− mice, revealed elevated levels of ROS, mitochondrial dysfunction and elevated levels of monoamine oxidase A (MAO-A) (Irwin et al., 2003; Menazza et al., 2010; Sorato et al., 2014; Figure 2), one of the major contributors to ROS production in the mitochondria (Canton et al., 2014).