CREM and obesity due to melanocortin 4 receptor deficiency: It is known that iron homeostasis in obesity is impaired and in fact our signature highlights a key regulator of iron homeostasis.32 Finally, it is well known that fertility could be negatively affected by obesity.33 In our signature we find the FHL-5 gene which encodes a protein coordinately expressed with activator of cAMP-responsive element modulator (CREM) known to confer a powerful transcriptional activation function.