[Rare diseases with epigenetic background]

Rare diseases with epigenetic background arise due to dysregulation of factors/processes that control epigenetic modifications of chromatin and miRNA level. They are usually caused by point mutations or chromosomal aberrations, such as deletions, which occur de novo during early embryonic development. They represent a heterogeneous group of multisystem diseases that mostly affect the nervous system and account for intellectual disability, mild to severe, of affected people. Studies on animal models not only provide a better insight into the molecular mechanisms of the observed anomalies and allow us to causally link the initial alteration in the genome with disease symptoms, but also deliver invaluable data that facilitate the design of effective therapies. Patients suffering from these diseases should receive comprehensive medical care, undergo adequate behavioral and/or occupational therapies, and have access to advanced treatment methods. This work provides information on typical symptoms, molecular basis and the current state of knowledge about selected rare diseases with epigenetic background.