The development of sequencing technologies and their increased accessibility in clinical services and genetic laboratories have considerably accelerated the identification of genetic variants associated with rare diseases. Among these, Mendelian disorders of the epigenetic machinery (MDEM) are rare monogenic diseases characterized by the presence of mutations in genes encoding epigenetic regulators that play a key role in organismal development and cellular functions. Loss of function of these regulators is expected to lead to epigenetic modifications that profoundly affect genome expression and cellular identity. The current challenge is to determine whether and how these epigenomic alterations drive the mechanisms underlying the clinical manifestations in patients suffering from this class of diseases.

Cover photo: Causes leading to modifications in individuals’ epigenome: presence of a pathogenic variant, aging, environmental factors. From “Genetic diseases of the epigenetic machinery”, Maud de Dieuleveult, Guillaume Velasco (page 914 of this issue) (© Biorender.com).

https://doi.org/10.1051/medsci/2024181