Lack of association of a functional single nucleotide polymorphism of PTPN22, encoding lymphoid protein phosphatase, with susceptibility to biopsy-proven giant cell arteritis

Objective. To assess the possible association between PTPN22 1858C→T polymorphism and susceptibility to giant cell arteritis (GCA) and to determine if this polymorphism is implicated in the clinical expression of this vasculitis. Methods. Ninety-six patients with biopsy-proven GCA and 229 ethnically matched controls from the Lugo region of Northwest Spain were studied using molecular methods. All individuals were of Spanish Caucasian origin. Genotyping of PTPN22 gene 1858C→T polymorphism was performed by real time polymerase chain reaction technology, using TaqMan 5′ allelic discrimination assay. Results. No significant differences in allele or genotype frequencies for PTPN22 polymorphism were observed between patients with GCA and controls or when patients were stratified by presence of polymyalgia rheumatica (n = 38) or severe ischemic manifestations (n = 47). Conclusion. Our results do not support potential involvement of PTPN22 gene polymorphism in the susceptibility or clinical expression of GCA.