%0 Journal Article
%T No Association between FC¦ÃR3B Copy Number Variation and Susceptibility to Biopsy-Proven Giant Cell Arteritis
%A Emma Dunstan
%A Sue Lester
%A Rachel Black
%A Maureen Rischmueller
%A Helen Chan
%A Alex W. Hewitt
%A Catherine L. Hill
%J Arthritis
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/514914
%X Objective. To determine the relationship between FCGR3B gene copy number variation (CNV) and biopsy proven giant cell arteritis (GCA). Methods. FCGR3B CNV was determined in 139 Australian biopsy proven GCA patients and 162 population matched controls, using a duplex qPCR assay and RNase P as the reference gene. Copy number was determined using Copy Caller software (v.1.0, Applied Biosystems, USA). CNV genotypes were classified into 3 groups (<2, 2, 3+) for analysis purposes, and analysis was performed using logistic regression. Results. All GCA patients had a positive temporal artery biopsy, and the most common presenting symptoms were visual disturbance and temporal headache. The mean age of patients at biopsy was 74 years (range 51¨C94) and 88/139 (63%) were female. The frequency of low (<2) FCGR3B copy number was comparable between GCA patients ( %) and controls ( %), as was the frequency of high (3+) FCGR3B copy number (15/130 (10.8%) in GCA patients versus 13/162 (8.0%) in controls). Overall there was no evidence that FCGR3B CNV frequencies differed between GCA patients and controls ( , , ). Conclusion. FCGR3B CNV is not associated with GCA; however, replicate studies are required. 1. Introduction Giant cell arteritis (GCA), also known as temporal arteritis, is a systemic inflammatory vasculitis which primarily affects medium to large extracranial arteries of the head and neck and can result in stroke and blindness. GCA typically affects people aged over 50 years and incidence rates increase with advancing age, peaking around 80 years of age [1]. GCA is 2-3 times more likely to affect females and is more commonly diagnosed in Caucasians than in any other ethnic background with the highest incidence observed in populations of Scandinavian descent [2]. The pathogenesis of GCA is not understood, although environmental, infectious, and genetic risk factors have been implicated. Familial aggregation and established associations with HLA-DR4 provide evidence for a genetic component to GCA [3¨C5]. Multiple genetic association studies have been performed on a number of immune response genes. However, the majority of these studies have been performed on a single GCA cohort from north-western Spain and, to date, have failed to confirm any additional genetic associations. One gene of interest is Fc gamma receptor 3B (FCGR3B) which exhibits gene copy number variation (CNV), an important source of quantitative genetic variation. Copy number variation is a departure from the normal diploid number of genes ( ) which may arise through gene duplication and deletion
%U http://www.hindawi.com/journals/arthritis/2013/514914/