Gene copy number and risk of autoimmunity

Individuals with fewer than two copies of the gene FCGR3B are more susceptible to a variety of autoimmune disorders, including lupus, according to a study.
Evidence is accumulating that, in addition to gene mutations, variation in the actual number of copies of individual genes can influence susceptibility to common diseases. It was previously shown that variation in the copy number of FCGR3B, a cell-surface receptor that contributes to the protective functions of the immune system, is associated with susceptibility to a kidney disease called glomerulonephritis. Timothy Aitman and colleagues now report that FCGR3B copy number variation is associated more broadly with autoimmune disorders, including lupus, microscopic polyangiitis, and Wegener’s granulomatosis. The small group of individuals who have no copies of FCGR3B have a dramatically elevated risk of autoimmune disease. This is among the first demonstrations that common naturally occurring variation in gene copy number can influence human susceptibility to disease.
Author contact:
Timothy Aitman (Imperial College, London, UK)
Tel: +44 208 383 4253; E-mail: t.aitman@csc.mrc.ac.uk