The administration of A. muciniphila grown under mucin-depleted conditions is effective in reducing obesity and improve intestinal barrier integrity in obese mice (Shin et al., 2019), controls fat mass storage and glucose homeostasis in obese and type 2 diabetic mice (Everard et al., 2013), and it has been previously described that bariatric surgery improves its abundance (Damms-Machado et al., 2015; Tremaroli et al., 2015; Palleja et al., 2016; Medina et al., 2017). The gene discussed is MUC5AC; the disease is obesity due to melanocortin 4 receptor deficiency.