 The result of this is that the channels are active for a shorter amount of time and, consequently, cell excitability is decreased.There are also a number of point mutations resulting in patients with phenotypes reminiscent of episodic ataxia and SCA6 (C271Y, G293R and R1664Q) or familial hemiplegic migraine and SCA6 (R583Q and I1710T).C287Y and G293R are both located in the pore region of domain 1 and are present in a single family each.