On the other hand, although the phenotype of Pcyt2+/− mice is identical with the littermate controls during the first 2 months of age, Pcyt2 +/− mice progressively gaine weight which at 24–28 weeks of age leads to the development of adult-onset hypertrigyceridemia, liver steatosis and obesity [74]. Here, PCYT2 is linked to obesity due to melanocortin 4 receptor deficiency.