This study analyzed a large cohort of patients with genetic epilepsies using hierarchical clustering analysis to identify homogeneous subgroups defined by specific genetic causes, each showing distinct clinical and EEG patterns.
We included 277 patients (52.3% female; median age at last follow-up 8.1 years, range 0–40). Drug resistance occurred in 58.8% and severe DD/ID in 35.4% of patients. EEG data at onset were available for 107 individuals. Neonatal onset was associated with a higher rate of drug resistance (71.4%; odds ratio [OR] 2.0, 95% CI 1.05–3.77), movement disorders (60.7%; OR 3.7, 95% CI 2.02–6.82), and severe DD/ID (71.4%; OR 7.0, 95% CI 3.66–13.49). Slow EEG background activity and multifocal epileptiform discharges were associated with both drug resistance and severe DD/ID. HCA identified genotype-phenotype groupings, including clusters involving SCN1A, PRRT2, STXBP1, KCNQ2, SCN2A, CHD2, SYNGAP1, and MECP2, each linked to specific clinical and EEG features.