FOXG1 belongs to the forkhead family of transcription factors which is characterized by a distinct forkhead domain. The specific function of this gene has not yet been determined; however, it may play a role in the development of the brain and telencephalon.

HFK1 was found to be highly conserved among mammalian species and possibly among birds. Northern blot analysis detected a 3.2-kb transcript in human and mouse fetal brain and adult mouse brain. In situ hybridization with sections of mouse embryo and human fetal brain demonstrated that HFK1 expression was restricted to the neuronal cells in the telencephalon, with strong expression in the developing dentate gyrus and hippocampus.