title: Screening for replication of genome-wide SNP associations in sporadic ALS.
abstract: We recently reported a joint analysis of genome-wide association (GWA) data on 958 sporadic amyotrophic lateral sclerosis (ALS) cases and 932 controls from Ireland and the publicly available data sets from the United States and the Netherlands. The strongest pooled association was rs10260404 in the dipeptidyl-peptidase 6 (DPP6) gene. Here, we sought confirmation of joint analysis signals in both an expanded Irish and a Polish ALS cohort. Among 287 522 autosomal single-nucleotide polymorphisms (SNPs), 27 were commonly associated on joint analysis of the Irish, US and Dutch GWAs. These 27 SNPs were genotyped in an expanded Irish cohort (312 patients with SALS; 259 controls) and an additional Polish cohort (218 patients; 356 controls). Eleven SNPs, including rs10260404, reached a final P-value below 0.05 in the Irish cohort. In the Polish cohort, only one SNP, rs6299711, showed nominal association with ALS. Pooling of data for 1267 patients with ALS and 1336 control subjects did not identify any association reaching Bonferroni significance (P<1.74 x 10(-7)). The present strategy did not reveal any consistently associated SNP across four populations. The result for DPP6 is surprising, as it has been replicated elsewhere. We discuss the possible interpretations and implications of these findings for future ALS GWA studies both within and between populations.
authors.affiliation: Department of Clinical Neurological Sciences, Royal College of Surgeons in Ireland, Dublin 2, Ireland. scronin@rcsi.ie
authors.forename: Simon
authors.initials: S
authors.lastname: Cronin
authors.forename: Barbara
authors.initials: B
authors.lastname: Tomik
authors.forename: Daniel G
authors.initials: DG
authors.lastname: Bradley
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Slowik
authors.forename: Orla
authors.initials: O
authors.lastname: Hardiman
mesh_terms: D000368:Aged; D000690:Amyotrophic Lateral Sclerosis / Q000235:genetics*; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases; D005260:Female; D020022:Genetic Predisposition to Disease; D015894:Genome, Human; D055106:Genome-Wide Association Study; D006801:Humans; D008297:Male; D008875:Middle Aged; D009419:Nerve Tissue Proteins / Q000235:genetics; D010447:Peptide Hydrolases / Q000235:genetics; D020641:Polymorphism, Single Nucleotide; D015221:Potassium Channels / Q000235:genetics
chemical_list: D009419:Nerve Tissue Proteins; D015221:Potassium Channels; C503535:DPP6 protein, human; D010447:Peptide Hydrolases; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases