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  • Updated 11.29.2020
  • Released 03.15.1999
  • Expires For CME 11.29.2023

Epilepsy in infancy with migrating focal seizures



Epilepsy in infancy with migrating focal seizures (EIMFS) is a devastating developmental and epileptic encephalopathy of early infantile onset characterized by the occurrence of very frequent focal seizures arising from multiple foci in both hemispheres independently and seizure migration between cerebral hemispheres along with profound developmental impairment and often with regression. Seizure onset is in the first 6 months of life with a progressive increase in frequency and change in semiology over the first few months. Between 2011 and 2019 pathogenic variants in more than 24 genes have been implicated in this syndrome. However, most of the currently available reports show pathogenic genetic variants in the KCNT1 gene. Other major genes implicated are SCN2A, KCNQ2, ATP1A3, CDKL5, GABRA1, GABRB1, GABRB3, GABRG2, HCN1, SCN1A, SCN8A, SLC12A5, SLC25A22, and TBC1D24 and this list is expanding. The seizures are mostly refractory to currently available antiepileptic drugs. Novel precision medicine treatment options are being explored. In this article, the authors focus on etiology, clinical features, and advances in the management of epilepsy in infancy with migrating focal seizures.

Key points

• Epilepsy in infancy with migrating focal seizures is a rare, intractable, early infantile epileptic encephalopathy with onset in first 6 months of life.

• There are multifocal bilateral independent seizure foci and the seizures migrate from 1 hemisphere to the other.

• It results in severe global developmental delay and regression, along with acquired microcephaly.

• Variants in the KCNT1 gene are most frequently associated with epilepsy in infancy with migrating focal seizures.

Historical note and terminology

A report in 1995 by Coppola and colleagues described 14 infants who developed migrating partial seizures (16). The first seizures had occurred at the mean age of 3 months, and the full pattern was developed between 1 month and 10 months of age. Patients regressed developmentally. Three of them died between 7 months and 8 years of age. Only 2 patients had seizures controlled by medication, and 3 patients resumed psychomotor development. Similar cases were subsequently reported in other countries such as Japan (41), European countries (51; 49; 24), Israel (23), the United States (32), and India (42).

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