This report reviews a case of calculation-induced idiopathic generalized epilepsy (IGE) that, unlike most patients with IGE, was refractory to medications. This patient had a family history of a similar condition in a relative of hers who did not have identical manifestations, and a mother who had migraine. Our observations illustrate that the occurrence of IGE in families usually follows rather complex patterns of inheritance and that some of them can be refractory to therapy.