The human FCGRIIB gene, located on 1q23.3, includes a number of single nucleotide polymorphisms (SNPs); amongst the nonsynonymous SNPs, the T-to-C transition in exon 5 (rs1050501), which leads to a replacement of isoleucine at position 232 by threonine (FCGRIIB-I232T variant), is relatively frequent and correlates with autoimmune disease [16–19]. The gene discussed is FCGR2B; the disease is autoimmune disease.