title: Similar familial risk in multiple sclerosis subgroups.
abstract: BACKGROUND
  A subgroup of patients diagnosed with multiple sclerosis (MS) present with no oligoclonal bands (OCB) in the cerebrospinal fluid (CSF). Several studies report different clinical characteristics and genetic associations between the two groups.
  
  
  OBJECTIVE
  To investigate whether the OCB negative subgroup has a distinct etiology from band positive MS.
  
  
  METHODS
  Using nationwide registers to estimate familial risks, which reflect the genetic contribution of a disease.
  
  
  RESULTS
  Odds ratios of MS were similar for relatives to band positive and negative patients.
  
  
  CONCLUSIONS
  From the perspective of familial liability, MS without OCB is etiologically closely related to the dominant subgroup of OCB positive MS.
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Jie
authors.initials: J
authors.lastname: Song
authors.affiliation: Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Virginija
authors.initials: V
authors.lastname: Karrenbauer
authors.affiliation: Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Ali
authors.initials: A
authors.lastname: Manouchehrinia
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden/Lung and Allergy Unit, Astrid Lindgren Children's Hospital, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Catarina
authors.initials: C
authors.lastname: Almqvist
authors.affiliation: Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Jan
authors.initials: J
authors.lastname: Hillert
authors.affiliation: Institute of Environmental Medicine (IMM), Karolinska Institutet, Stockholm, Sweden/Rheumatology Unit, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Helga
authors.initials: H
authors.lastname: Westerlind
mesh_terms: D000328:Adult; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000134:cerebrospinal fluid* / Q000453:epidemiology / Q000235:genetics*; D043025:Oligoclonal Bands / Q000134:cerebrospinal fluid*; D010375:Pedigree; D012042:Registries; D013548:Sweden / Q000453:epidemiology
chemical_list: D043025:Oligoclonal Bands
keywords: Multiple sclerosis; epidemiology; familial risks; genetics; oligoclonal band negative; oligoclonal band positive