Two South Indian Children with KCNT1-Related Malignant Migrating Focal Seizures of Infancy – Clinical Characteristics and Outcome of Targeted Treatment with Quinidine

KCNT1 gene encodes a sodium-gated potassium channel subunit that plays an important role in regulating excitability in neurons. Quinidine is a partial antagonist of this channel. We report the clinical characteristics of two south Indian children with KCNT1-related epileptic encephalopathy. Both of them had very high seizure burden which were resistant to antiepileptic and dietary therapy. Pharmacological response to quinidine in these children is described. Case 1 had 30% reduction in seizure burden at 20 mg/kg/day and 80% reduction at 36 mg/kg/day; case 2 had 30% reduction at 20 mg/kg/day. Serial electrocardiography was used to monitor the cardiotoxicity. Serum quinidine levels were not measured due to nonavailability. A critical review on the current status of targeted treatment of KCNT1-related epileptic encephalopathies with quinidine is attempted.