Because of the redundancy of genes across multiple pathways, and the presence of interrelated pathways, we broadly grouped them into three major clusters of signaling processes corresponding to neurotrophic signaling (including Axon guidance, and Synaptogenesis), fibrosis (including the IPA annotation of Fibrosis, GP6 signaling and Inhibition of MMPs), and inflammation (including Osteoarthritis, Granulocyte Adhesion and Rheumatoid Arthritis) (Fig. 1E, Supplementary Fig. 2B). Here, GP6 is linked to osteoarthritis.