Changes in the Pattern of DNA Methylation Associate with Twin Discordance in SLE

This is the first high-throughput analysis of DNA methylation in autoimmune diseases. We have used a cohort of MZ twins discordant for three diseases whose clinical signs often overlap: systemic lupus erythematosus (SLE), rheumatoid arthritis and dermatomyositis. Only MZ twins discordant for SLE featured widespread changes in the DNA methylation status of a significant number of genes. Individual analysis confirmed the existence of DNA methylation and expression changes in genes relevant to SLE pathogenesis. Our findings not only identify potentially relevant DNA methylation markers for the clinical characterization of SLE patients but also support the notion that epigenetic changes may be critical in the clinical manifestations of autoimmune disease. Total DNA isolated by standard procedures from 59 White Blood Cell (WBC) samples corresponding to monozygotic twins discordant for three different autoimmune diseases: systemic lupus erythematosus (SLE), rheumatoid arthritis (RA) and dermatomyositis (DM) and two additional controls for each MZ twin pair.