We first performed a genome scan using the whole sample, and were able to detect loci confirmed to be associated with RA such as the major histocompatibility complex on chromosome 6, PTPN22 on chromosome 1, and TRAF1-C5 on chromosome 9 (data not shown), which proved the validity of the current method. The gene discussed is PTPN22; the disease is rheumatoid arthritis.