title: NordicDB: a Nordic pool and portal for genome-wide control data.
abstract: A cost-efficient way to increase power in a genetic association study is to pool controls from different sources. The genotyping effort can then be directed to large case series. The Nordic Control database, NordicDB, has been set up as a unique resource in the Nordic area and the data are available for authorized users through the web portal (http://www.nordicdb.org). The current version of NordicDB pools together high-density genome-wide SNP information from ∼5000 controls originating from Finnish, Swedish and Danish studies and shows country-specific allele frequencies for SNP markers. The genetic homogeneity of the samples was investigated using multidimensional scaling (MDS) analysis and pairwise allele frequency differences between the studies. The plot of the first two MDS components showed excellent resemblance to the geographical placement of the samples, with a clear NW-SE gradient. We advise researchers to assess the impact of population structure when incorporating NordicDB controls in association studies. This harmonized Nordic database presents a unique genome-wide resource for future genetic association studies in the Nordic countries.
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden. monica.leu@ki.se
authors.forename: Monica
authors.initials: M
authors.lastname: Leu
authors.forename: Keith
authors.initials: K
authors.lastname: Humphreys
authors.forename: Ida
authors.initials: I
authors.lastname: Surakka
authors.forename: Emil
authors.initials: E
authors.lastname: Rehnberg
authors.forename: Juha
authors.initials: J
authors.lastname: Muilu
authors.forename: Päivi
authors.initials: P
authors.lastname: Rosenström
authors.forename: Peter
authors.initials: P
authors.lastname: Almgren
authors.forename: Juha
authors.initials: J
authors.lastname: Jääskeläinen
authors.forename: Richard P
authors.initials: RP
authors.lastname: Lifton
authors.forename: Kirsten Ohm
authors.initials: KO
authors.lastname: Kyvik
authors.forename: Jaakko
authors.initials: J
authors.lastname: Kaprio
authors.forename: Nancy L
authors.initials: NL
authors.lastname: Pedersen
authors.forename: Aarno
authors.initials: A
authors.lastname: Palotie
authors.forename: Per
authors.initials: P
authors.lastname: Hall
authors.forename: Henrik
authors.initials: H
authors.lastname: Grönberg
authors.forename: Leif
authors.initials: L
authors.lastname: Groop
authors.forename: Leena
authors.initials: L
authors.lastname: Peltonen
authors.forename: Juni
authors.initials: J
authors.lastname: Palmgren
authors.forename: Samuli
authors.initials: S
authors.lastname: Ripatti
mesh_terms: D016022:Case-Control Studies; D030541:Databases, Genetic; D005788:Gene Pool; D014644:Genetic Variation; D005828:Genetics, Population; D055106:Genome-Wide Association Study; D006801:Humans; D020407:Internet; D012537:Scandinavian and Nordic Countries