•7 of 9 patients with GGE reduced ≥ 50% their tonic-clonic seizure frequency on LCM.•All 7 patients remained seizure free for > 1 year, and 2 of them for > 5 years.•In 2 of the 9 patients, both with Juvenile Absence Epilepsy, absences aggravated.•One aggravation consisted on a myoclonia and absence status, in a patient with no history of myoclonia.•VEEG paralleled clinical improvement but didn't change in a case of absence worsening.