We differentiated three R29</span>4X iPSC lines and their isogenic wild type control iPSC into neurons with high efficiency and consistency, and observed characteristic RTT pathology in R294X neurons.
Clinicians need to be alerted to the variable presentation of Rett syndrome including the milder phenotypes of cases with the p.R133C or p.R294X mutation.
Two missense mutations, R133C (33.3%) and R306C (23.3%), and a nonsense mutation, R294X (13.3%), were common in 30 patients with atypical RTT, including the preserved speech variant (PSV).