Furthermore, genetically affected embryos are accessible to only small number of laboratories, and the derivation of affected ESC lines requires connection to a PGD performing center. The discovery of human induced pluripotent stem cells (hiPSCs) has provided an alternative model, by allowing the derivation of ESC-like cells in vitro from virtually any type of somatic cell. Additionally, hiPSCs, as opposed to ESCs, can be generated from patients with defined clinical phenotypes, thus allowing to link in vitro phenotypes to the clinical presentation in vivo. The hiPSC model system shows great promise in overcoming many of the problems with the approaches discussed above and elucidating the pathogenesis of neurodevelopmental disorders.
