Similar to the elevated levels of sex steroids in UGT2B17 KO, higher levels of phosphatidylcholine derivatives consistently correlated with a reduced risk of obesity, diabetes and heart failure (Supplementary Fig. 5A, B,E), whereas higher levels of sphingolipids were associated with an increased risk of obesity and arthritis (Supplementary Fig. 5A, G). This evidence concerns the gene UGT2B17 and obesity due to melanocortin 4 receptor deficiency.