We have characterized the wide range of pathophysiological features of the cardio-metabolic syndrome and genome-wide gene expression patterns that are altered in rats of the BN.GK-Nidd/gk1 congenic strain designed to carry alleles of the spontaneously diabetic (type 2) GK rat across diabetes and obesity QTLs mapped to RNO1. This evidence concerns the gene GK and obesity due to melanocortin 4 receptor deficiency.