title: Lack of association between the apolipoprotein E gene and aneurysmal subarachnoid hemorrhage in an Italian population.
abstract: OBJECTIVE
  The results of genome-wide scan studies have suggested the presence of a genetic risk factor for aneurysmal subarachnoid hemorrhage (SAH) on chromosome 19 (at 19p13). The apolipoprotein E (APOE) gene is located in this chromosomal region and encodes a protein that exerts several neuroprotective and neurotrophic functions in the brain. The purpose of this study was to evaluate whether a particular allele or genotype of the APOE gene would modify the occurrence or the clinical features of SAH.
  
  
  METHODS
  Genomic DNA was extracted from 146 patients with aneurysmal SAH and 222 age- and sex-matched healthy controls and genotyped for the triallelic polymorphism of the APOE gene (epsilon2, epsilon3, and epsilon4). Allele and genotype frequencies were compared between patients and controls. The clinical characteristics of the disease were compared according to the different APOE genotypes. Allele and genotype frequencies of the APOE gene polymorphism were nearly identical in cases and controls. Patients carrying the APOE epsilon4 allele had a significantly higher Hunt and Hess grade on admission (p = 0.0014). There was no significant relationship between any of the other clinical characteristics and the APOE genotype.
  
  
  CONCLUSIONS
  The authors' data do not support the hypothesis that genetic variations within the APOE gene are associated with aneurysmal SAH. However, the APOE gene influences the disease phenotype and may be regarded as a disease modifier gene.
authors.affiliation: Division of Neurosurgery, Department of Neuroscience, University of Turin, Italy. marco.fontanella@unito.it
authors.forename: Marco
authors.initials: M
authors.lastname: Fontanella
authors.forename: Innocenzo
authors.initials: I
authors.lastname: Rainero
authors.forename: Salvatore
authors.initials: S
authors.lastname: Gallone
authors.forename: Elisa
authors.initials: E
authors.lastname: Rubino
authors.forename: Chiara
authors.initials: C
authors.lastname: Rivoiro
authors.forename: Walter
authors.initials: W
authors.lastname: Valfrè
authors.forename: Diego
authors.initials: D
authors.lastname: Garbossa
authors.forename: Chiara
authors.initials: C
authors.lastname: Nurisso
authors.forename: Alessandro
authors.initials: A
authors.lastname: Ducati
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Pinessi
mesh_terms: D000328:Adult; D000368:Aged; D001057:Apolipoproteins E / Q000235:genetics*; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D005787:Gene Frequency; D005838:Genotype; D023261:Glasgow Outcome Scale; D006801:Humans; D007558:Italy; D008297:Male; D008875:Middle Aged; D013345:Subarachnoid Hemorrhage / Q000208:ethnology / Q000235:genetics*
chemical_list: D001057:Apolipoproteins E