Monogenic inheritance

Monogenic/monogenic inheritance or "simple" inheritance refers to a term in genetics that defines the involvement of a single gene in the expression of a characteristic (phenotype) (see also polygenic inheritance).

In a monogenic or "simple" inheritance, only one gene is responsible for the expression of the trait. In the case of a disease that follows a monogenic inheritance (monogenic disease), the defect is caused by a single gene (i.e.: mono-gene) = "one-gene disease". Characteristic for monogenic (also monogenetic) diseases is that they follow Mendel's rules in their inheritance pattern. Monogenic diseases are often manifested in early childhood.

It is estimated that currently > 10,000 monogenic diseases with a clearly differentiable phenotype are known. Most of these diseases are very rare, but due to their large number they are widespread overall. It is estimated that about 1% of newborns are affected.

Since one and the same gene can be affected by different mutations, monogenic diseases can also occur in different forms or manifestations (phenotype). For example, > 500 mutations of the PAH gene (phenylketonuria), which codes for the enzyme phenylalanine hydroxylase, are currently known.

In polygenic inheritance, several genes are responsible for the expression of the phenotype.

1. Martini PG (2019) A new era for rare genetic diseases. Hum Gene Ther doi: 10.1089/hum.2019.090.
2. Martorana D et al (2017) Monogenic Autoinflammatory Diseases with Mendelian Inheritance: Genes, Mutations, and Genotype/Phenotype Correlations.Front Immunol 8:344.
3. Tada H et al (2019) Monogenic, polygenic, and oligogenic familial hypercholesterolemia. Curr Opin Lipidol. 2019 May 22nd doi:10.1097/QCO.0000000000000000000563.
4. of Rheenen W eet al (2019) Genetic correlations of polygenic disease traits: from theory to practice. Nat Rev Genet doi: 10.1038/s41576-019-0137-z.