Obesity has also been linked to altered HA catabolism (e.g., hyaluronidase [HYAL]1/2, cell migration-inducing hyaluronidase 1/transmembrane protein 2 [CEMIP/TMEM2]) [30,31] and higher systemic HA turnover, which may influence mammary HA levels. This evidence concerns the gene CEMIP2 and obesity due to melanocortin 4 receptor deficiency.