In the investigation of the pathophysiology of diabetes in the Cohen rat model, we previously identified in CDs/y through linkage analysis a quantitative trait locus (QTL) on rat chromosome 4 that incorporates NADH dehydrogenase (ubiquinone) 1 alpha sub-complex 4 (Ndufa4), a nuclear gene that affects mitochondrial function [8]. Here, COXFA4 is linked to diabetes mellitus.