ABSTRACT Introduction and objective: Rett syndrome (RTT) is a rare, genetically determined neurodevelopmental disorder that represents one of the most frequent monogenic causes of severe intellectual disability in females. The aim of the study is to present the current state of knowledge on Rett syndrome, with particular emphasis on pathophysiology, clinical presentation, diagnostic criteria, and contemporary and emerging therapeutic strategies. Review methods: A comprehensive literature search was performed in the PubMed, Google Scholar and Scopus dabatases from 2001–2025 using mainly the key words: ‘‘Rett syndrome’’, ‘‘MECP2’’, ‘‘Rett syndrome treatment’’. Over 60% of the selected articles were published within the last five years. Brief description of the state of knowledge: Rett syndrome is mostly caused by mutations in the MECP2 gene, leading to impaired regulation of gene expression, synaptic dysfunction, and abnormalities in the functioning of multiple systems. The clinical presentation comprises developmental regression, severe neurological disorders and numerous somatic complications. The introduction of trofinetide is an important step in the treatment of RTT, although treatment remains mainly symptomatic.