title: High-resolution whole-genome association study of Parkinson disease.
abstract: We performed a two-tiered, whole-genome association study of Parkinson disease (PD). For tier 1, we individually genotyped 198,345 uniformly spaced and informative single-nucleotide polymorphisms (SNPs) in 443 sibling pairs discordant for PD. For tier 2a, we individually genotyped 1,793 PD-associated SNPs (P<.01 in tier 1) and 300 genomic control SNPs in 332 matched case-unrelated control pairs. We identified 11 SNPs that were associated with PD (P<.01) in both tier 1 and tier 2 samples and had the same direction of effect. For these SNPs, we combined data from the case-unaffected sibling pair (tier 1) and case-unrelated control pair (tier 2) samples and employed a liberalization of the sibling transmission/disequilibrium test to calculate odds ratios, 95% confidence intervals, and P values. A SNP within the semaphorin 5A gene (SEMA5A) had the lowest combined P value (P=7.62 x 10(-6)). The protein encoded by this gene plays an important role in neurogenesis and in neuronal apoptosis, which is consistent with existing hypotheses regarding PD pathogenesis. A second SNP tagged the PARK11 late-onset PD susceptibility locus (P=1.70 x 10(-5)). In tier 2b, we also selected for genotyping additional SNPs that were borderline significant (P<.05) in tier 1 but that tested a priori biological and genetic hypotheses regarding susceptibility to PD (n=941 SNPs). In analysis of the combined tier 1 and tier 2b data, the two SNPs with the lowest P values (P=9.07 x 10(-6); P=2.96 x 10(-5)) tagged the PARK10 late-onset PD susceptibility locus. Independent replication across populations will clarify the role of the genomic loci tagged by these SNPs in conferring PD susceptibility.
authors.affiliation: Department of Neurology, Mayo Clinic College of Medicine, Rochester, MN, USA.
authors.forename: Demetrius M
authors.initials: DM
authors.lastname: Maraganore
authors.forename: Mariza
authors.initials: M
authors.lastname: de Andrade
authors.forename: Timothy G
authors.initials: TG
authors.lastname: Lesnick
authors.forename: Kari J
authors.initials: KJ
authors.lastname: Strain
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Farrer
authors.forename: Walter A
authors.initials: WA
authors.lastname: Rocca
authors.forename: P V Krishna
authors.initials: PV
authors.lastname: Pant
authors.forename: Kelly A
authors.initials: KA
authors.lastname: Frazer
authors.forename: David R
authors.initials: DR
authors.lastname: Cox
authors.forename: Dennis G
authors.initials: DG
authors.lastname: Ballinger
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002874:Chromosome Mapping / Q000379:methods*; D005260:Female; D005787:Gene Frequency / Q000235:genetics; D008040:Genetic Linkage / Q000235:genetics; D005819:Genetic Markers / Q000235:genetics; D020022:Genetic Predisposition to Disease / Q000235:genetics; D014644:Genetic Variation; D015894:Genome, Human; D005838:Genotype; D006239:Haplotypes; D006801:Humans; D015810:Linkage Disequilibrium / Q000235:genetics; D008297:Male; D008565:Membrane Proteins / Q000235:genetics*; D008875:Middle Aged; D009419:Nerve Tissue Proteins / Q000235:genetics*; D010300:Parkinson Disease / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D039961:Semaphorins
chemical_list: D005819:Genetic Markers; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; C491228:SEMA5A protein, human; D039961:Semaphorins