title: Copy number variation in autoimmunity--importance hidden in complexity?
abstract: Copy number variation, namely regions of the genome that can be either deleted or duplicated in a variable way, has emerged as an important source of genetic variance in the human genome. Genes with immunological functions are particularly prone to copy number variation, in part because this is a mechanism to expand the recognition repertoire; however, immunological genes not directly involved in immune recognition are also copy number variable but, despite the link between immunological function and copy number variation, very few copy number variants (CNVs) have been found to be associated with autoimmune diseases, even in recent large genome-wide CNV-association studies. Nonetheless, CNVs in FCGR3B, DEFB4, CCL3L1, C4A/B and NCF1 have been suggested to be associated with autoimmune diseases, although there is conflicting evidence in all cases. The reasons for the lack of definitive data on CNV-autoimmunity associations, as well as the technical challenges for the field are the focus of this review.
authors.affiliation: Medical Inflammation Research, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Lina M
authors.initials: LM
authors.lastname: Olsson
authors.forename: Rikard
authors.initials: R
authors.lastname: Holmdahl
mesh_terms: D001327:Autoimmune Diseases / Q000235:genetics*; D015551:Autoimmunity / Q000235:genetics*; D019742:Chemokines, CC / Q000235:genetics; D003181:Complement C4 / Q000235:genetics; D056915:DNA Copy Number Variations; D058851:GPI-Linked Proteins / Q000235:genetics; D018628:Gene Dosage; D020022:Genetic Predisposition to Disease; D014644:Genetic Variation; D015894:Genome, Human; D006801:Humans; D019255:NADPH Oxidases / Q000235:genetics; D017452:Receptors, IgG / Q000235:genetics; D023083:beta-Defensins / Q000235:genetics
chemical_list: C492767:CCL3L1 protein, human; D019742:Chemokines, CC; D003181:Complement C4; C106641:DEFB4A protein, human; C428200:FCGR3B protein, human; D058851:GPI-Linked Proteins; D017452:Receptors, IgG; D023083:beta-Defensins; D019255:NADPH Oxidases; C060505:neutrophil cytosolic factor 1