Spastic ataxias refer to disorders in which most patients have a clinical presentation with equal contribution of pyramidal and cerebellar involvement such as in spastic ataxia of Charlevoix-Saguenay, and in SPG7, SAX2, SPG43 and RNF170 mutation carriers ((Synofzik and Schüle, 2017). The gene discussed is KIF1C; the disease is spastic ataxia.