title: Association of distinct variants in SORL1 with cerebrovascular and neurodegenerative changes related to Alzheimer disease.
abstract: BACKGROUND
  Single-nucleotide polymorphisms (SNPs) in 2 distinct regions of the gene for the sortilin-related receptor (SORL1) (bounded by consecutively numbered SNPs 8-10 and 22-25) were shown to be associated with Alzheimer disease (AD) in multiple ethnically diverse samples.
  
  
  OBJECTIVE
  To test the hypothesis that SORL1 is associated with brain magnetic resonance imaging (MRI) measurements of atrophy and/or vascular disease.
  
  
  METHODS
  We evaluated the association of 30 SNPs spanning SORL1 with MRI measures of general cerebral atrophy, hippocampal atrophy, white matter hyperintensities, and overall cerebrovascular disease in 44 African American and 182 white sibships from the MIRAGE Study. We performed single- and 3-SNP haplotype association analyses using family-based tests. Haplotypes found to be significantly associated with at least 1 MRI trait were tested for association with 6 pathological traits in a separate sample of 69 white patients with autopsy-confirmed AD.
  
  
  RESULTS
  In white patients, white matter hyperintensities were associated with multiple markers in the region encompassing SNPs 6 to 10, whereas cerebral and hippocampal atrophy were associated with markers from the region including SNPs 21 to 26. Examination of specific 3-SNP haplotypes from these 2 regions in the autopsy-confirmed cases of AD revealed association of white matter disease with SNPs 8 to 10 and association of hippocampal atrophy with SNPs 22 to 26. The haplotype CGC at SNPs 8 to 10 was associated with fewer white matter changes in the clinical (P<.001) and autopsy (P=.02) samples.
  
  
  CONCLUSIONS
  Variants of SORL1 previously associated with AD are also associated with MRI and neuropathological measures of neurodegenerative and cerebrovascular disease. These findings not only support the hypothesis that multiple areas in SORL1 are of functional importance but also raise the possibility that multiple SORL1 variants influence amyloid precursor protein or endothelial lipoprotein processing or both in different regions of the brain.
authors.affiliation: Genetics Program, Department of Medicine, Room L320, Boston University School of Medicine, 715 Albany St, Boston, MA 02118, USA.
authors.forename: Karen
authors.initials: K
authors.lastname: T Cuenco
authors.forename: Kathryn L
authors.initials: KL
authors.lastname: Lunetta
authors.forename: Clinton T
authors.initials: CT
authors.lastname: Baldwin
authors.forename: Ann C
authors.initials: AC
authors.lastname: McKee
authors.forename: Jianping
authors.initials: J
authors.lastname: Guo
authors.forename: L Adrienne
authors.initials: LA
authors.lastname: Cupples
authors.forename: Robert C
authors.initials: RC
authors.lastname: Green
authors.forename: Peter H
authors.initials: PH
authors.lastname: St George-Hyslop
authors.forename: Helena
authors.initials: H
authors.lastname: Chui
authors.forename: Charles
authors.initials: C
authors.lastname: DeCarli
authors.forename: Lindsay A
authors.initials: LA
authors.lastname: Farrer
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000150:complications / Q000235:genetics*; D002561:Cerebrovascular Disorders / Q000209:etiology / Q000235:genetics* / Q000473:pathology; D005260:Female; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D026502:LDL-Receptor Related Proteins / Q000235:genetics*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D026901:Membrane Transport Proteins / Q000235:genetics*; D008954:Models, Biological; D009410:Nerve Degeneration / Q000209:etiology / Q000235:genetics*; D009483:Neuropsychological Tests; D011110:Polymorphism, Genetic
chemical_list: D026502:LDL-Receptor Related Proteins; D026901:Membrane Transport Proteins; C102582:SORL1 protein, human