The 2017 International League Against Epilepsy (ILAE) classification suggested that the term “genetic generalized epilepsies” (GGEs) should be used for the broad group of epilepsies with generalized seizure types and generalized spike-wave activity on EEG, based on a presumed genetic etiology [1]. Within this framework, idiopathic generalized epilepsies (IGEs) are described as a subset of GGEs and include only four epileptic syndromes: childhood absence epilepsy (CAE), juvenile absence epilepsy (JAE), juvenile myoclonic epilepsy (JME), and epilepsy with generalized tonic-clonic seizures alone (GTCA) [2].

The recent 2022 ILAE definition of IGEs is based on the current state of knowledge and reflects a community consensus and is designed to evolve as knowledge advances. Indeed, among patients presenting with a syndrome compatible with the 2022 definition of IGEs, we still observe a significant proportion of patients presenting with specific clinical features, refractory seizures, or drug-resistant epilepsies.

In the first part of this work, we open the discussion of the boundaries of IGEs and GGEs, or what is accepted within the clinical spectrum of a definite IGE.

In the second part, we discuss three entities and three syndromes that have been described in the literature and that may either constitute rare features of IGEs or a distinct differential diagnosis.

Indeed, antiseizure medications (ASMs) and therapeutic education remain the mainstay of IGE management and are effective in most patients, but these entities and syndromes are often associated with drug-resistance, or pseudo-drug-resistance when inappropriate pharmacologic treatment is used. Therefore, their recognition by clinicians may allow for a more individualized approach and improve the management of patients presenting with such entities.