TLR5 and obesity due to melanocortin 4 receptor deficiency: Vijay-Kumar et al. [47] demonstrated that mice deficient in TLR5 exhibit obesity, hyperphagia, dyslipidaemia, hypertension and insulin resistance, and that they also show an altered composition of gut microbiota, such as increased Firmicutes (54%) and lower Bacteroidetes (39.8%).