Genetic link of type 1 diabetes susceptibility loci with rheumatoid arthritis in Pakistani patients

Rheumatoid arthritis (RA) and type 1 diabetes (T1D) are two autoimmune disorders that have been reported to co-occur in the same subjects or in different subjects from the same family. This suggests the sharing of disease susceptibility loci between RA and T1D. This study was aimed to find out such susceptibility loci that are common in both T1D and RA in Pakistani population. A total of 366 Pakistanis comprising related and unrelated RA cases and controls were recruited. Blood samples were collected from all patients followed by DNA isolation. Thirty-one single-nucleotide polymorphisms (SNPs) previously reported to be associated with T1D were genotyped in RA cases and controls using TaqMan SNP genotyping assays. Data was analyzed using FamCC software. We have identified seven SNP associations that survived multiple testing corrections using false discovery rate: SKAP2 /rs7804356 ( p = 2.47E-04), GLIS3 /rs7020673 ( p = 2.86E-04), GSDMB /rs2290400 ( p = 23.48E-04), BACH2 /rs11755527 ( p = 9.16E-04), C6orf173 / rs9388489 ( p = 3.11E-03), PRKCQ/DKFZp667F0711 / rs947474 ( p = 4.53E-03), and DLK1 / rs941576 ( p = 9.51E-03). Our results support the presence of overlapping loci between RA and T1D in Pakistani patients.