FGF8 is a critical morphogen governing embryonic development through regulation of cell proliferation, differentiation, and migration 1. Mechanistically, FGF8 establishes graded positional cues that modulate early target genes and activate the Ras-ERK signaling pathway to specify distinct neural regions 2. During CNS development, FGF8 functions as the primary organizer at the midbrain-hindbrain boundary, directing anterior-posterior patterning and maintaining regional identity 3. FGF8 also regulates telencephalic patterning by affecting anteroposterior and dorsoventral neural progenitor identity while controlling the balance between GABAergic and glutamatergic neuron differentiation 1. Beyond the CNS, FGF8 is essential for normal development of the gonadotropin-releasing hormone neuronal system, with mutations causing congenital hypogonadotropic hypogonadism with or without anosmia (Kallmann syndrome), accounting for approximately 12% of cases 4. FGF8 also regulates limb outgrowth; thalidomide's teratogenic effects involve inhibition of cereblon-mediated ubiquitin ligase activity, which normally supports FGF8 expression and limb formation 5. Clinically, FGF8 dysregulation is implicated in multiple developmental disorders and has been identified as a component in endometrial cancer pathogenesis 6, highlighting its importance across developmental and disease contexts.