Analysis of two autoimmunity genes, IRAK1 and MECP2, in giant cell arteritis

The Xq28 region, containing IRAK and MECP2, represent a common susceptibility locus for a high number of autoimmune diseases. Our aim in the present study was to evaluate the influence of the IRAK1 and MECP2 autoimmunity-associated genetic variants in the giant cell arteritis (GCA) susceptibility and its clinical subphenotypes.

We analysed a total of 627 female biopsy-proven GCA patients and 1,520 female healthy controls of Spanish Caucasian origin. Two polymorphisms, rs1059702 and rs17345, located at IRAK1 and MECP2, respectively, were genotyped using TaqMan® allelic discrimination assays.

No association with any of the analysed polymorphisms was evident when genotype and allele frequencies were compared between GCA patients and controls (rs1059702: allelic p-value=0.699, OR=0.96, CI 95% 0.80-1.17; rs17435: allelic p-value=0.994, OR=1.00, CI 95% 0.84-1.19). Likewise, the subphenotype analysis yield similar negative results.

We have assessed for the first time the possible role of IRAK1 and MECP2 autoimmune disease-associated polymorphisms in GCA. Our data suggest that IRAK1 rs1059702 and MECP2 rs17435 genetic variants do not play a significant role in GCA susceptibility or severity.