title: Familial intracranial aneurysms.
abstract: BACKGROUND
  We set out to determine the prevalence of incidental intracranial aneurysms in first-degree relatives aged 30 years or more of people with intracranial aneurysms, and to see if polycystic kidney disease contributes to the aggregation of familial intracranial aneurysms.
  
  
  METHODS
  91 families with two or more affected members had previously been identified from a 14 year series of 1150 intracranial aneurysm patients treated at the University Hospital of Kuopio, Finland. Magnetic resonance angiography was used as a preliminary screening method, followed by conventional four-vessel angiography to verify suspected aneurysms. Participants were also screened for polycystic kidneys by ultrasonography.
  
  
  RESULTS
  Incidental aneurysms were detected in 40 individuals: 38 of 438 individuals from 85 families without polycystic kidney disease or other diagnosed heritable disorders, and two of 22 individuals from six families known to have polycystic kidney disease. The crude and age-adjusted prevalence of incidental intracranial aneurysms among screened first-degree relatives was 8.7 (SE 1.3)% (95% CI 6.2-11.7) and 9.1 (1.4)% (6.2-11.7), respectively, for the familial group and the crude prevalence for the polycystic kidney group was 9.1 (6.1)% (1.1-29.2).
  
  
  CONCLUSIONS
  Our results demonstrate a high prevalence of incidental intracranial aneurysms among first-degree relatives aged 30 years or older of patients with the condition and indicate that the risk of having an aneurysm is about four times higher for a close relative than for someone from the general population. Also, polycystic kidney disease families are a small fraction of the familial intracranial aneurysm families.
authors.affiliation: Department of Neurosurgery, University Hospital of Kuopio, Finland.
authors.forename: A
authors.initials: A
authors.lastname: Ronkainen
authors.forename: J
authors.initials: J
authors.lastname: Hernesniemi
authors.forename: M
authors.initials: M
authors.lastname: Puranen
authors.forename: L
authors.initials: L
authors.lastname: Niemitukia
authors.forename: R
authors.initials: R
authors.lastname: Vanninen
authors.forename: M
authors.initials: M
authors.lastname: Ryynänen
authors.forename: H
authors.initials: H
authors.lastname: Kuivaniemi
authors.forename: G
authors.initials: G
authors.lastname: Tromp
mesh_terms: D000328:Adult; D000368:Aged; D017542:Aneurysm, Ruptured / Q000150:complications; D005260:Female; D005387:Finland / Q000453:epidemiology; D006801:Humans; D002532:Intracranial Aneurysm / Q000150:complications / Q000175:diagnosis / Q000235:genetics*; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D007690:Polycystic Kidney Diseases / Q000150:complications / Q000000981:diagnostic imaging / Q000235:genetics*; D015995:Prevalence; D011446:Prospective Studies; D013345:Subarachnoid Hemorrhage / Q000209:etiology; D014463:Ultrasonography