Digenic inheritance and genetic modifiers

Abstract

Digenic inheritance (DI) concerns pathologies with the simplest form of multigenic aetiology, implicating more than one gene (and perhaps the environment). True DI is when biallelic or even triallelic mutations in two distinct genes, in cis or in trans, are necessary and sufficient to cause pathology with a defined diagnosis. In true DI, a heterozygous mutation in each of two genes alone is not associated with a recognizable phenotype. Well-documented diseases with true DI are so far rare and follow non-Mendelian inheritance. DI is also encountered when by serendipity, pathogenic mutations responsible for two distinct disease entities are co-inherited, leading to a mixed phenotype. Also, we can consider many true monogenic Mendelian conditions, which demonstrate impressively broad spectrum of phenotypes due to pseudo-DI, as a result of co-inheriting genetic modifiers (GM). I am herewith reviewing examples of GM and embark on presenting some recent notable examples of true DI, with wider discussion of the literature. Undeniably, the advent of high throughput sequencing is bound to unravel more patients suffering with true DI conditions and elucidate many important GM, thus impacting precision medicine.

http://ift.tt/2fIOyHa