Elective genetic and genomic testing

Elective genetic and genomic testing are DNA tests performed for an individual who does not have an indication for testing. An elective genetic test analyzes selected sites in the human genome while an elective genomic test analyzes the entire human genome. Some elective genetic and genomic tests require a physician to order the test to ensure that individuals understand the risks and benefits of testing as well as the results. Other DNA-based tests, such as a genealogical DNA test do not require a physician's order. Elective testing is generally not paid for by health insurance companies. With the advent of personalized medicine, also called precision medicine, an increasing number of individuals are undertaking elective genetic and genomic testing. Genetic testing for a variety of disorders has seen many advances starting with cytogenetics to evaluate human chromosomes for aneuploidy and other chromosome abnormalities. The development of molecular cytogenetics involving techniques such as fluorescence in situ hybridization (FISH) followed, permitting the detection of more subtle changes in the karyotype. Techniques to determine the precise sequence of nucleotides in DNA by DNA sequencing, notably Sanger sequencing was developed in the 1970s. In the 1980s the DNA microarray appeared, permitting laboratories to find copy number variants associated with disease that are below the level of detection of cytogenetics but too large to be detected by DNA sequencing. In recent years the development of high-throughput or next-generation sequencing has dramatically lowered the cost of DNA sequencing permitting laboratories to evaluate all 20,000 genes of the human genome at once through exome sequencing and whole genome sequencing. A catalogue of the many uses of these techniques can be found in the section: genetic testing. Most elective genetic and genomic testing employs either a DNA microarray or next-generation sequencing. Historically, all laboratory tests were initiated and ordered by a physician or mandated by a state.