MACROD2 and obesity due to melanocortin 4 receptor deficiency: Salas-Perez et al. established a connection between the gut microbiota and DNA methylation in individuals with obesity [50], specifically noting that the effect of Ruminococcus abundance on BMI was mediated by the methylation of the macro domain containing 2 gene (MACROD2) and differentially methylated region gene (DMR) (p = 0.035).