In humans, the loss of one copy of the BDNF gene, caused by deletion of the region containing the gene in the WAGR (Wilms tumor, aniridia, genitourinary anomalies, and intellectual disability) syndrome or by a chromosomal inversion, is associated with syndromic phenotypes linked to hyperphagia and obesity [27,28]. Here, BDNF is linked to obesity due to melanocortin 4 receptor deficiency.