title: Anticipation and phenotype in familial intracranial aneurysms.
abstract: BACKGROUND
  In familial intracranial aneurysms there is evidence for genetic heterogeneity, probably from mutations at separate loci.
  
  
  OBJECTIVE
  To compare demographic and clinical features in patients of families with familial intracranial aneurysm and different patterns of inheritance; and to compare the ages of patients with subarachnoid haemorrhage (SAH) in affected parent-child pairs to determine whether there is anticipation.
  
  
  METHODS
  Pedigrees for 53 families with familial intracranial aneurysms were constructed, divided into patterns of inheritance suggestive or not suggestive of autosomal dominant transmission. Demographic and clinical features were compared. The age at time of SAH in affected parent-child pairs was compared using the Wilcoxon test.
  
  
  RESULTS
  No differences in demographic or clinical features were found between families compatible with an autosomal dominant pattern of inheritance and those with a non-dominant pattern. In families with affected members in two successive generations the age at time of SAH in parents was 55.2 years and in children 35.4 years (mean difference, 19.8 years, p<0.001).
  
  
  CONCLUSIONS
  Phenotypes are similar in families with and without a probable autosomal dominant pattern of inheritance. Thus in future genetic studies on familial intracranial aneurysms, stratification according to phenotype is not likely to be useful. Anticipation probably occurs, as affected parents are significantly older at the time of SAH than their affected children.
authors.affiliation: Department of Neurology, Rudolf Magnus Institute of Neuroscience, University Medical Centre Utrecht, PO box 85500, 3500 GA Utrecht, Netherlands. ij.m.ruigrok@neuro.azu.nl
authors.forename: Y M
authors.initials: YM
authors.lastname: Ruigrok
authors.forename: G J E
authors.initials: GJ
authors.lastname: Rinkel
authors.forename: C
authors.initials: C
authors.lastname: Wijmenga
authors.forename: J
authors.initials: J
authors.lastname: Van Gijn
mesh_terms: D000328:Adult; D017668:Age of Onset; D000368:Aged; D003710:Demography; D005260:Female; D020022:Genetic Predisposition to Disease; D005820:Genetic Testing; D006801:Humans; D040582:Inheritance Patterns; D002532:Intracranial Aneurysm / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D010375:Pedigree; D010641:Phenotype; D011379:Prognosis; D013345:Subarachnoid Hemorrhage / Q000209:etiology* / Q000235:genetics*