Burst-Suppression EEG in Early Infantile Developmental and Epileptic Encephalopathies: Phenotype, Genotype, and Outcome

Pathogenic variants in *KCNQ2*, *STXBP1*, and 21 other genes causing severe neonatal burst-suppression EEG

A retrospective cohort of 110 patients with burst-suppression EEG in the first months of life revealed a genetic etiology in 62.7% of cases, involving 23 genes including KCNQ2 (n=24) and STXBP1 (n=16). New associations were described with DPM1, GRIN2A, KCNT2, PIGO, PURA, WWOX, and candidate genes. The typical burst-suppression pattern (bursts longer than suppressions) strongly correlated with KCNQ2 and STXBP1 variants, guiding diagnostic orientation and early initiation of sodium channel blockers. Mortality remained high (25%) and 72.5% retained persistent seizures at 6.5 years of follow-up.

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This large series underscores the profoundly monogenic nature of EIDEE-BS and the diagnostic value of early EEG features for genotype orientation. New gene associations extend paneling options for these often undiagnosed syndromes. Early sodium channel blocker initiation in KCNQ2 cases remains the central therapeutic issue.