Species of Firmicutes could upregulate IFN-γ production and significant increased ratio of Firmicutes/Bacteroidetes has been reported associated with not only with ASD (77, 79), but also with other conditions that were found to be more prevalent within ASD subjects, such as obesity and diabetes (24, 80, 81). The gene discussed is IFNG; the disease is obesity due to melanocortin 4 receptor deficiency.