Mice that were deficient in myeloid Prkaa1, when bred to Ldlr–/– mice, displayed enhanced macrophage inflammation, increased plasma cholesterol and triglyceride levels, and a phenotype of enhanced diet-induced obesity and insulin resistance as well as accelerated atherosclerosis (Cao et al., 2016). The gene discussed is LDLR; the disease is obesity due to melanocortin 4 receptor deficiency.