Peptidoglycan interacts with the host through nucleotide-binding oligomerization domain-containing protein (NOD)-1 and −2 cytosolic receptors, which in turn are responsible for developing insulin resistance and maintaining low-grade chronic inflammation, thus contribute to obesity.48 Additionally, some novel control-enriched pathways involved in pyrimidine biosynthesis (PWY0–162, PWY-7211, PRPP-PWY, PWY-7199, PWY-7210), all ranking within top 20, were also identified from this meta-analysis. The gene discussed is NOD1; the disease is obesity due to melanocortin 4 receptor deficiency.