Even though the contribution of these types of association studies remains uncertain, it has been suggested that common genetic variants may contribute to common diseases, supporting the role for continued association studies.
Each SNP represents a difference in a single DNA building block, called a nucleotide.
 A relatively short single-stranded nucleic-acid chain usually consisting of 2 to 20 nucleotides that is synthesized to match a region where a mutation is known to occur, and then used as a probe.
While these data have the potential to inform investigations into disease etiologies and thereby advance medicine, the question of how to adequately control both false positive and false negative rates remains.
 Genome-wide association studies are a relatively new way for scientists to identify genes involved in human disease.
The development of new drugs can be made far cheaper and more rapid by selecting participants in drug trials based on their genetically determined response to drugs.
Recent advances in molecular technologies have resulted in the ability to screen hundreds of thousands of SNPs and tens of thousands of gene expression profiles.
The genetic basis for complex disease remains unclear.
Association studies look for an increased frequency of a particular genotype at a candidate gene locus in cases compared with controls.
 Over 1,500 genetic tests are now available clinically, with nearly 300 more available on a research basis only.
The number of genetic tests is predicted to increase by 25% annually.
The following Clinical Reference Document provides the evidence to support the Genetic Testing Time Tool.
The following bookmarks are available to move around the Clinical Reference Document.
There is higher risk for prenatal testing which requires a sample from the amniotic fluid or chorionic villus during pregnancy.