Randomized control trials have shown that weight loss significantly increases plasma ITLN1 concentration42 whereas hyper‐insulinaemic induction in healthy individuals reduces ITLN1 plasma concentration.43 Decreased levels of ITLN1 have been associated with obesity in patients with ovarian cancer,43 and levels of ITLN1 measured before patients were diagnosed with colorectal cancer have been confined to nonobese individuals suggesting it has a role in weight loss.44 The gene discussed is ITLN1; the disease is obesity due to melanocortin 4 receptor deficiency.