INS and obesity due to melanocortin 4 receptor deficiency: Turpin-Nolan et al. noted that increased CerS1 mRNA expression in the skeletal muscles of HFD-fed obese insulin resistant mice was accompanied by elevated skeletal muscle C18:0 ceramide content, whereas CerS1-deficient mice (CerS1ΔSkM) displayed decreased content of skeletal muscle C18:0-Cer and were protected from HFD-induced obesity  (57).