HLA haplotypes in multiple case families with rheumatoid arthritis.

In 9 families of which at least two members were affected by rheumatoid arthritis (RA), no specific combination of HLA genes, i.e., HLA haplotype was found to be associated with transmission of disease susceptibility. The results suggested an important role of HLA-DR4 in the etiology of RA, irrespective of other HLA markers. In addition, it may be concluded that genetic markers other than DR4 may act together with this HLA antigen in determining which individuals are at risk of developing this rheumatic disorder.