Anosmin-1 (ANOS1)

Anosmin-1 is a secreted extracellular matrix-associated glycoprotein encoded by the ANOS1 gene, previously known as KAL1, located on the X chromosome[4][6]. It is 680 amino acids in length and contains a cysteine-rich region, a WAP-like domain, four fibronectin type III domains, and a C-terminal region rich in basic histidines and prolines[6]. Anosmin-1 is expressed primarily in the central nervous system—especially the olfactory bulb, cerebral cortex, retina, cerebellum, and spinal cord—and to a lesser extent in tissues such as kidney, testis, skin, and vascular endothelium[6]. Functionally, anosmin-1 plays a critical role in neurodevelopment by regulating neural crest and neuronal precursor migration, axon guidance, and angiogenesis. It modulates FGFR1 signaling, enhances FGF8-FGFR1 complex formation, and suppresses BMP5 and WNT3A signaling, thereby orchestrating neural crest cell EMT/MET transitions[4][6]. Anosmin-1 also directly binds to and activates VEGFR2, promoting VEGF-dependent angiogenesis in the developing olfactory bulb[1][2]. Clinically, loss or mutation of ANOS1 results in X-linked Kallmann syndrome, manifesting as congenital anosmia and hypothalamic hypogonadotropic hypogonadism due to defects in neural migration and olfactory bulb development[4][6]. Anosmin-1 is thus considered essential for normal reproductive and olfactory system development but is not currently characterized as a therapeutic target for any approved drugs. Research continues into its involvement in neurodegenerative and developmental disorders, and its interactions with growth factor pathways make it a subject of interest in disease mechanisms involving neurogenesis and angiogenesis[6][3][4][1][2][5].

Other names

ADMLXKALKAL1KALIG1KALIG-1WFDC19Adhesion molecule-like X-linkedKallmann syndrome proteinWAP four-disulfide core domain 19HH1HHAKMSKallmann syndrome interval gene 1