Genetic analysis of CRHRA1 and CRHRA2 microsatellites and their association with rheumatoid arthritis in South Asian and Caucasian populations of the East Midlands, UK.

Two microsatellites from corticotropin releasing hormone (CRH) gene locus (CRHRA1 and CRHRA2) were reported to be associated with rheumatoid arthritis (RA) in Caucasians. This study aims to replicate the association in a South Asian (SA) and Caucasian RA sample from the East Midlands, UK. DNA from 281 South Asians (111 patients, 43 siblings, 127 controls) and 287 Caucasians (116 patients, 64 siblings, 107 controls) were genotyped. The Odds Ratio for carrying at least one copy of the CRHRA1*10 risk allele was 1.32 (Confidence Interval, CI=0.77-2.28) in Caucasians and 1.55 (CI=0.92-2.63) in South Asians, indicative of a trend for association. The risk allele CRHRA2*14 was lower in South Asians compared to Caucasians (5.5%-8.6% vs. 17.7-18.2 %; P<0.005). Significant linkage disequilibrium was observed between CRHRA1 and CRHRA2 in both cohorts. CRHRA1*10 was the frequently transmitted allele in SA patients. A non-significant association was observed with CRHRA1*10 allele in both RA populations.