Proliferation and Differentiation Deficits are a Major Convergence Point for Neurodevelopmental Disorders.

Several lines of evidence suggest that proliferation and differentiation in neural stem cells (NSCs) are a major convergence point of neurodevelopmental disorders (NDDs). Most genes with truncating mutations are implicated in NSC proliferation and differentiation (e.g., MBD5, CDKL5, and MECP2). Similarly, reciprocal deletion/duplication copy-number variants (CNVs), such as 1q21.1 and 16p11.2, are inversely correlated with head size. In addition, pathways such as MAPK, mTOR, and RAS, which are important in cancer, a disease of uncontrolled cell proliferation, are implicated in NDDs. These deficits are a measurable output of patient-derived induced neural progenitor cells, and may represent a diagnostic tool and a possible clinical intervention point for molecular therapies, irrespective of genotype. Crown