The function of Ensembl gene identifier ENSG00000129682 (FGF13, fibroblast growth factor 13) is as follows. Microtubule-binding protein which directly binds tubulin and is involved in both polymerization and stabilization of microtubules (By similarity). Through its action on microtubules, may participate in the refinement of axons by negatively regulating axonal and leading processes branching (By similarity). Plays a crucial role in neuron polarization and migration in the cerebral cortex and the hippocampus (By similarity). Regulates voltage-gated sodium channel transport and function (PubMed:15282281, PubMed:33245860, PubMed:36696443). May also play a role in MAPK signaling (By similarity). Required for the development of axonal initial segment-targeting inhibitory GABAergic synapses made by chandelier neurons (By similarity). {ECO:0000250|UniProtKB:P70377, ECO:0000269|PubMed:15282281, ECO:0000269|PubMed:33245860, ECO:0000269|PubMed:36696443}.