BLK and rheumatoid arthritis: Associations with the BLK locus have also been identified in rheumatoid arthritis (RA), systemic sclerosis (SSc), Sjӧgren’s syndrome (SjS), Kawasaki’s disease (KD), antiphospholipid syndrome (APS) and maturity-onset diabetes of the young (MODY), thus justifying a focused mechanistic study of this locus (Hom et al., 2008; Borowiec et al., 2009; Yin et al., 2009; Gourh et al., 2010; Tsuchiya et al., 2010; Lessard et al., 2013).