Aim:

To assess genotype-phenotype correlation in EIEE

Methodology:

Retrospective chart review over 4 year period, structural malformations and metabolic abnormalities were excluded.

Results:

Sixteen children were included. (3 children had mutation in KCNT1 gene, 2 in KCNQ2, 2 in SCN1A, 2 in SCN2A and 1 each with SYHJ1, SPTAN1, WWOX, QARS, SLC12A5 and CDKL5 gene. 1 child had mutation in both HEPACAM and FOXRED gene. Mean age at onset of seizures was 48 days (1 to 180 days). Tonic seizures, focal clonic, multifocal clonic, myoclonic and atypical absence were the most common seizures. Alternating focal clonic seizures was seen in KCTN1 and SCN2A group, tonic seizures in KCNQ2, SYHJ1, SPTAN1, WWOX, QARS, myoclonic seizures in HEPACAM, CDKL5 and SLC12A5 group. Febrile seizures and febrile status epilepticus was seen in SCN1A and SLC12A5. Initial EEG was normal in SCN1A, CDKL5 and HEPACAM group. Hypsarythmic pattern was seen in KCNQ2, SHHJ1, SPTAN1, WWOX and SCN2A group, burst suppression was seen in KCNT1 and KCNQ2 group.  MRI Brain was normal in all except mild diffuse cerebral atrophy in KCNT1 and KCNQ2 and ponto cerebellar hypoplasia with delayed myelination in SPTAN1. Polypharmacy was used in all children. Relatively better seizure control was seen in SCN2A, SCN1A and KCNT1 group. One child with KCNQ2 expired due to an intercurrent illness; others are left with profound developmental disability with autistic traits.

Conclusion:

EIEEs are an important cause of infantile epileptic encephalopathy. Early genetic diagnosis helps in prognostication and make appropriate antiepileptic drug choices.