Whole exome sequencing: principles and diagnostic capabilities

Abstract

Diagnostics of genetic diseases in clinical routine often presents a challenge. In particular, most of hereditary diseases are exceptionally rare and therefore unfamiliar to practicing physicians. Furthermore, even if the diagnosis of a particular genetic condition appears convincing on the level of clinical evidence, the causative mutation often remains unknown due to limitations in DNA testing procedures. Recently developed high-throughput sequencing technologies (Next Generation Sequencing, NGS; synonym: massive parallel sequencing) provide a breakthrough in medical genetics. While in the past genetic testing was limited to a single gene or, at best, to a small number of genes, NGS is compatible with a large-scale DNA analysis. One of the most popular applications of NGS is whole exome sequencing (WES), which allows simultaneous reading of coding sequences (exons) of all known genes. Although this technology exists only for a few years, its use has already led to discovery of the causes of more than 150 genetic syndromes. Furthermore, WES may be recommended for the use in clinical routine for selected patients with orphan disease, especially for the families with multiple affected relative. It is likely that WES will become a powerful screening tool in the near future. This review discusses general principles of WES as well as the applications of this technology in medicine.