To determine the advances made in the genetics of systemic lupus erythematosus (SLE) or Sjögren's syndrome as the era of genome-wide association and high-throughput single nucleotide typing begins. Several genome-wide association studies have been performed in SLE but there are no such studies published or in progress for Sjögren's syndrome. Genetics and the functional significance of risk alleles in the interferon pathway are being worked out in detail. This is especially true for STAT4 and IRF5. Gene copy number variation, a major source of genetic variability, is important for several genes that impart risk for SLE. An X chromosome copy number dose effect has recently been identified. Genetic evaluation of Sjögren's syndrome is limited to small studies that have concentrated on genes already shown to be risk factors in SLE. Knowledge of the genetics of SLE is advancing rapidly, whereas that of Sjögren's syndrome lags behind considerably.
