An identical twin pair discordant for rheumatoid arthritis and ankylosing spondylitis.
MacGregor AJ., Fox H., Ollier WE., Snaith ML., Silman AJ.
Both rheumatoid arthritis (RA) and ankylosing spondylitis (AS) have an increased familial occurrence and each disease is associated with the inheritance of specific HLA antigens. We report a pair of identical twin brothers with discordant disease phenotypes: one developed AS at the age of 26, and the other developed RA at the age of 55. The twins possessed both of the disease susceptibility antigens HLA B27 and DR4. Differences in the twins' environmental exposure are discussed.