CDKN1C and obesity due to melanocortin 4 receptor deficiency: In addition to the potential relevance to the rare human disorders that involve either elevated expression of Cdkn1c or gain in function mutations of this gene, SRS and IMAGe syndrome [18], worldwide obesity has nearly tripled in the last 40 years, resulting in over 650 million obese adults and an estimated 41 million children under the age of 5 years being overweight or obese (WHO).