title: Incidence and outcome of epilepsy syndromes with onset in the first year of life: A retrospective population-based study.
abstract: OBJECTIVE
  Population-based studies on infantile epilepsy syndromes are scarce. Our aim was to provide syndrome-specific data on the incidence and outcome of epilepsy in a population-based cohort of infants with epilepsy onset in the first year.
  
  
  METHODS
  Included were all infants born in 1997 through 2006 whose epileptic seizures started before 12 months of age and who were residents of the Helsinki University Hospital district at the time of seizure onset. Patients were ascertained from hospital statistics, and all patient charts were reviewed. A reevaluation of the epilepsy syndromes, age at onset, etiology, and outcome at 24 months of age was based on data abstracted from the patient files.
  
  
  RESULTS
  Inclusion criteria were fulfilled by 158 infants, of whom 92% were followed until age 24 months or death. The incidence of epilepsy in the first year was 124 of 100,000. An epilepsy syndrome recognized by the revised organization of epilepsies by ILAE was identified in 58% of the patients. The most common syndromes were West syndrome (41/100,000) and benign familial or nonfamilial infantile epilepsy (22/100,000). Etiology was structural-metabolic in 35%, genetic in 17%, and unknown in 48%. Early age at onset was associated with structural-metabolic etiology. Seven infants (4.4%) died before age 2 years. One infant with an SCN2A mutation died of sudden unexplained death in epilepsy (SUDEP). At 24 months, 58% of all children included in the cohort were seizure-free, and 46% had both seizure freedom and age-appropriate cognitive development. Age at onset was not associated with outcome when etiology was controlled for.
  
  
  CONCLUSIONS
  Benign familial and nonfamilial infantile epilepsy appears to be more common than previously suggested, second only to West syndrome. Early age at onset is not an independent risk factor for poor outcome.
authors: Children's Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland. eija.gaily@hus.fi.
authors: Eija
authors: E
authors: Gaily
authors: Children's Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.|Folkhälsan Institute of Genetics, Helsinki, Finland.
authors: Markus
authors: M
authors: Lommi
authors: Children's Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.
authors: Risto
authors: R
authors: Lapatto
authors: Folkhälsan Institute of Genetics, Helsinki, Finland.|Neuroscience Center, University of Helsinki, Helsinki, Finland.|Research Programs Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland.
authors: Anna-Elina
authors: AE
authors: Lehesjoki
mesh_terms: D015331:Cohort Studies; D018672:Community Health Planning; D004569:Electroencephalography; D004827:Epilepsy / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000235:genetics / Q000401:mortality*; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D008297:Male; D017063:Outcome Assessment, Health Care; D012307:Risk Factors
keywords: Epilepsy syndrome; Incidence; Infantile epilepsy; Outcome