SIGMAR1 and atypical Rett syndrome: The Sigma1R agonist ANAVEX 2-73 (blarcamesine) has demonstrated disease-modifying improvements in preclinical models of the neurodegenerative disorder Rett syndrome, and is currently in phase 2b/3 clinical trials for Alzheimer’s disease (NCT03790709) and Parkinson’s disease dementia (NCT03774459) (Table 3) [41,54,55,56,57].