Diabetes associated with mitochondrial DNA abnormalities accounts for up to 1% of all cases of diabetes (Murphy et al., 2008), referred to as “mitochondrial diabetes.” Glucose induces neuronal activation and reduces ROS production in the ventral medial nucleus of the hypothalamus owing to the key role of uncoupling protein 2 (UCP2) (Toda et al., 2016), which regulates neuronal activity by controlling ROS production (Coppola et al., 2007; Andrews et al., 2008; Diano and Horvath, 2012). Here, UCP2 is linked to maternally-inherited diabetes and deafness.