A quinidine non responsive novel KCNT1 mutation in an Indian infant with epilepsy of infancy with migrating focal seizures

Epilepsy of infancy with migrating focal seizures {a.k.a malignant migrating partial seizures of infancy (MMPSI)} is an uncommon epileptic encephalopathy with a poor prognosis. Migrating focal seizures with autonomic features, developmental stagnation and refractoriness to treatment are its key features. It is caused by genetic defects in various ion channels, most common being sodium activated potassium channel (KCNT1), found in up to 50% of cases. With advent of genetic diagnosis and precision medicine, many targeted therapies have been identified. Antagonist of KCNT1 coded ion channel like Quinidine has shown promising results in MMPSI. Here we report first mutation proven case of MMPSI from India. This child had a novel heterozygous missense mutation in exon10 of the KCNT1 gene (chr9:138650308; c.808C > C/G (p.Q270E)) which was pathogenic. Neither quinidine nor ketogenic diet could control his seizures. Ultimately, the child succumbed to his illness at nine months of age.