FGF17 is a secreted signaling molecule of the FGF8 subfamily that plays critical roles in embryonic development, particularly in brain patterning and organogenesis. 1 The protein contains a conserved core region and heparin binding site, with alternative splicing producing functional isoforms (FGF17a and FGF17b in humans). 1 During development, FGF17 is expressed in diverse tissues including the midbrain-hindbrain boundary, olfactory placode, and presomitic mesoderm, where it regulates neural patterning and ventral body wall closure through FGFR signaling. 2 FGF17 mutations contribute to congenital hypogonadotropic hypogonadism (CHH) and Kallmann syndrome in ~1.1% of affected individuals, frequently in conjunction with other FGF pathway gene mutations. 3 1 4 The mutations often present with syndromic features including dental agenesis, hearing loss, and hand malformations. 4 Beyond CHH/KS, FGF17 mutations associate with Dandy-Walker malformation and pituitary stalk interruption syndrome. 1 Clinically, FGF17 shows therapeutic promise in two major areas: neurodegeneration and cancer. FGF17 protects blood-brain barrier integrity following ischemic stroke through FGF receptor 3-mediated PI3K/AKT signaling and exhibits neuroprotective effects in aging-related cognitive decline. 5 1 FGF17-patterned dopaminergic progenitors outperform FGF8 in Parkinson's disease cell replacement therapy. 6 Elevated FGF17 expression predicts poor prognosis in acute myeloid leukemia and associates with altered PI3K-Akt and MAPK pathways, suggesting therapeutic targeting potential. 7 Additionally, dysregulation of BRD2-FGF17 signaling contributes to schizophrenia pathogenesis through impaired forebrain development. 8