SMAD2 and Familial paroxysmal ataxia: Curiously, downregulation of several genes involved in TGF-β signaling, including daf-14 (the orthologue of SMAD2), partially rescued worm incoordination with an unc-2 (orthologue of CACNA1A; genetic cause of SCA6 and episodic ataxia type 2) truncating variant60.