The implications of the early phases of human telencephalic development, involving neural stem cells (NSCs), in the etiology of cortical disorders remain elusive. Here, we explore the expression dynamics of cortical and neuropsychiatric disorder-associated genes in datasets generated from human NSCs across telencephalic fate transitions in vitro and in vivo. We identify risk genes expressed in brain organizers and sequential gene regulatory networks throughout corticogenesis, revealing disease-specific critical phases when NSCs may be more vulnerable to gene dysfunction and converging signaling across multiple diseases. Further, we simulate the impact of risk transcription factor (TF) depletions on neural cell trajectories traversing human corticogenesis and observe a spatiotemporal-dependent effect for each perturbation. Finally, single-cell transcriptomics of autism-affected patient-derived NSCs in vitro reveals recurrent expression alteration of TFs orchestrating brain patterning and NSC lineage commitment. This work opens perspectives to explore human brain dysfunction at early phases of development.