To compare the distribution and assess genetic associations of the PTPN22 R620W single-nucleotide polymorphism among South Asian (Asiatic Indian) patients with rheumatoid arthritis (RA) and ethnically matched controls.
DNA samples from 133 rheumatoid factor-positive South Asian RA patients and 149 control subjects from the East Midlands of the UK were genotyped for PTPN22 R620W polymorphism. Genotyping was performed by the polymerase chain reaction-restriction fragment length polymorphism method.
The PTPN22 *T allele frequency was lower than in the Caucasian populations, but the disease association was significant (odds ratio 5.87, 95% confidence interval 1.68-20.52). Similar association was observed for genotypes containing *T allele.
Our results suggest that the T variant acts as a susceptibility allele for autoantibody-positive RA among South Asians.