Forkhead Box G1 () is a member of the Forkhead family of genes with non-redundant roles in brain development, where alteration of this gene’s expression significantly affects the formation and function of the mammalian cerebral cortex. haploinsufficiency in humans is associated with prominent differences in brain size and impaired intellectual development noticeable in early childhood, while homozygous mutations are typically fatal. As such, has been implicated in a wide spectrum of congenital brain disorders, including the congenital variant of Rett syndrome, infantile spasms, microcephaly, autism spectrum disorder (ASD) and schizophrenia. Recent technological advances have yielded greater insight into phenotypic variations observed in FOXG1 syndrome, molecular mechanisms underlying pathogenesis of the disease, and multifaceted roles of expression. In this review, we explore the emerging mechanisms of in a range of transcriptional to posttranscriptional events in order to evolve our current view of how a single transcription factor governs the assembly of an elaborate cortical circuit responsible for higher cognitive functions and neurological disorders.Copyright © 2020 Hou, Ó hAilín, Vogel and Hanashima.