FCGR3B and anti-neutrophil cytoplasmic antibody-associated vasculitis: Low copy number of FCGR3B had been identified to be associated with a number of systemic autoimmune diseases, such as systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), ANCA-associated vasculitis (AAV), and anti-glomerular basement (anti-GBM disease) disease (Fanciulli et al., 2007; Willcocks et al., 2008; Mamtani et al., 2010; McKinney et al., 2010; Niederer et al., 2010; Zhou et al., 2010, 2011; Molokhia et al., 2011; Chen et al., 2014).