NTRK1 and rheumatoid arthritis: Janus kinases (JAK), a group of non-receptor tyrosine kinases, and signal transducer and activator of transcription (STAT), an intracellular receptor and transcription factor for JAK, have been implicated in the pathogenesis of inflammatory and autoimmune disorders, including rheumatoid arthritis (RA), psoriasis, Behçet’s disease, and Crohn’s disease [8–12].