"Navajo arthritis" reconsidered: relationship to HLA-B27.

"Navajo arthritis" was described in 1971 as an acute, self-limited, asymmetric polyarthritis of unknown etiology seen in Navajo Indian patients. This description was before published accounts relating HLA-B27 to certain seronegative arthropathies. Review of 92 cases of arthritis seen between 1977 through 1979 in adult Navajo Indians revealed 16 cases of complete Reiter's syndrome, 6 cases of incomplete Reiter's syndrome, and 7 cases of ankylosing spondylitis. The phenotype frequency of HLA-B27 in this Navajo population is 36% and, of the Reiter's syndrome and ankylosing spondylitis patients tested, 85% were found to be HLA-B27 positive. We suggest that "Navajo arthritis" may not be a unique form of arthritis affecting only the Navajo, but a variant of either Reiter's syndrome or ankylosing spondylitis.