KCNJ10 and Ataxia: Thus, a KCNJ10 mutation should be considered as a potential cause for ataxias with onsets between 2 and 6 months of age, particularly if they occur in members of breeds with British hunting terrier ancestry and if the ataxias are accompanied by one or more of the following: myokymia, neuromyotonia, seizures, and face rubbing.