INS and obesity due to melanocortin 4 receptor deficiency: However, it is noteworthy that further analyses based on Omics techniques [18] may allow to name the gut microbes associated with insulin resistance, providing a gut microbial signature for this phenotype, to be associated with the bacterial signature of obesity, already recognized in the increased Firmicutes to Bacteroidetes ratio, both in humans [5] and in mice [6].