title: Familial aggregation of cluster headache.
abstract: Several studies suggest a strong familial aggregation for cluster headache (CH), but so far none of them have included subjects with probable cluster headache (PCH) in accordance with the International Classification of Headache Disorders.
  
  
  OBJECTIVE
  To identify cases of probable cluster headache and to assess the familial aggregation of cluster headache by including these subjects.
  
  
  METHODS
  Thirty-six patients attending a headache consultation and diagnosed with trigeminal autonomic headaches were subjected to a questionnaire-based interview. A telephone interview was also applied to all the relatives who were pointed out as possibly affected as well as to some of the remaining relatives.
  
  
  RESULTS
  Twenty-four probands fulfilled the criteria for CH or PCH; they had 142 first-degree relatives, of whom five were found to have CH or PCH, including one case of CH sine headache. The risk for first-degree relatives was observed to be increased by 35- to 46-fold.
  
  
  CONCLUSIONS
  Our results suggest a familial aggregation of cluster headache in the Portuguese population.
authors.affiliation: Serviço de Neurologia, Hospital Prof. Dr. Fernando Fonseca, Portugal, Sintra.
authors.forename: Simão
authors.initials: S
authors.lastname: Cruz
authors.affiliation: Instituto Ciências Biomédicas Abel Salazar, Universidade do Porto, Portugal.
authors.forename: Carolina
authors.initials: C
authors.lastname: Lemos
authors.affiliation: Serviço de Neurologia, Centro Hospitalar do Porto, Hospital de Santo António, Portugal, Porto.
authors.forename: José Maria Pereira
authors.initials: JM
authors.lastname: Monteiro
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D000368:Aged; D003027:Cluster Headache / Q000235:genetics*; D005190:Family; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010375:Pedigree; D018570:Risk Assessment; D012307:Risk Factors; D011795:Surveys and Questionnaires; D055815:Young Adult