SIGMAR1 and atypical Rett syndrome: For example, ANAVEX 2-73 (blarcamesine), which has agonist activity both at the Sigma1R and at muscarinic receptors, is currently in clinical trials for neurodegenerative diseases (NCT03774459, NCT03790709; Alzheimer’s disease, Parkinson’s disease dementia, and Rett syndrome (which manifests with seizures in most patients)) and was granted FDA’s Orphan Drug Designation for infantile spasms in 2016 [41,42,54,55,56,57].