Rett syndrome: from the involved gene(s) to treatment

Rett syndrome (RTT) is a devastating genetic disorder that worldwide represents the most common genetic cause of severe intellectual disability in females. Most cases are caused by mutations in the X-linked MECP2 gene. The available molecular data suggest that MeCP2 is a key protein in the brain and that its level and functions cannot be altered without severe consequences in both genders. Importantly, in 2007, it was demonstrated that RTT in principle is a reversible condition and that MeCP2-related disorders can be treated even at late stages of disease progression. However, to develop clinical applications, the functional role(s) of MeCP2 and their relevance for RTT pathobiology must be clearly understood. This chapter presents current knowledge of MeCP2 functions and its etiological role in disease development, the most promising therapeutic strategies and those that may be relevant in the future, and the challenges associated with treating RTT.