Although FGF14 haploinsufficiency is associated with spinocerebellar ataxia (Dalski et al., 2005) and intrinsic excitability of cerebellar Purkinje neurons is reduced in Fgf14−/− mice (Shakkottai et al., 2009), the detailed multifactorial molecular mechanisms by which FGF14 affects neuronal excitability were not previously known. Here, FGF14 is linked to cerebellar ataxia.