Loss of function of the SWI/SNF-like chromatin remodeler ATRX (the causative gene in the ATR-X syndrome) results in enhanced replication stress and a significant impairment in neural progenitor growth, causing a reduction in neuron production and the size of the cerebral cortex [50,51]. The gene discussed is ATRX; the disease is Alpha-thalassemia - X-linked intellectual disability syndrome.