The HCN1 variant (c.365A>G, p.K122R) occurred de novo in a female patient presenting with myoclonic seizures and focal epileptiform anomalies on EEG, consistent with prior reports highlighting that LIDEE represents a clinically and electrographically distinct DEE syndrome including common seizure types as myoclonic–tonic, tonic, epileptic spasms, and myoclonic seizures, often accompanied by disorganized EEG background with low-voltage and multifocal epileptiform discharges [35]. Here, HCN1 is linked to Seizure.