Maximum likelihood identity-by-descent (IBD) sib pair analysis using a 3 locus haplotype NRAMP1-IL8RB-VIL1, or NRAMP1 alone, provided preliminary evidence (maximum LOD score = 1.01, p = 0.024) for a gene in this region of human chromosome 2q35 contributing to susceptibility to rheumatoid arthritis (RA). Candidacy for NRAMP1 as the disease susceptibility gene was supported by a significant bias (p < 0.048) toward transmission of the NRAMP1 promoter region allele 3 in affected offspring.