Two KCND3 gain of function variants previously associated with sudden unexplained death and cardiological syndrome (p.Leu450Phe and p.Val392Ile) [12,19], were described respectively in a patient with late-onset cerebellar ataxia [12] and in a patient with epileptic encephalopathy [19], with no evidence of cardiological issues. The gene discussed is KCND3; the disease is Epileptic encephalopathy.