Primer: SNP-associated studies and what they can teach us.

Single-nucleotide polymorphisms (SNPs) are single base-pair alterations in the DNA sequence that represent a major source of genetic heterogeneity. Well-developed and sophisticated technologies exist to measure and analyze the presence of SNPs, and SNP genotyping is an important tool with which to investigate other genetic variants. SNP-based, large-scale, genome-wide association studies are detecting many polymorphisms that can be used to evaluate the risk of various common traits, including rheumatic diseases. This increased knowledge of genetic risk could potentially be used to refine medical care in rheumatology clinics in the near future.