Disease-specific therapies (e.g., ketogenic diet in SLC2A1, stiripentol/fenfluramine in SCN1A) were effective in select cases.<h4>Significance</h4>Absence seizures are a common manifestation of different monogenic epilepsies, often associated with early onset, atypical clinical and/or EEG features, developmental delay or drug resistance. This evidence concerns the gene SCN1A and Global developmental delay.