title: 'Racial' differences in genetic effects for complex diseases.
abstract: 'Racial' differences are frequently debated in clinical, epidemiological and molecular research and beyond. In particular, there is considerable controversy regarding the existence and importance of 'racial' differences in genetic effects for complex diseases influenced by a large number of genes. An important question is whether ancestry influences the impact of each gene variant on the disease risk. Here, we addressed this question by examining the genetic effects for 43 validated gene-disease associations across 697 study populations of various descents. The frequencies of the genetic marker of interest in the control populations often (58%) showed large heterogeneity (statistical variability) between 'races'. Conversely, we saw large heterogeneity in the genetic effects (odds ratios) between 'races' in only 14% of cases. Genetic markers for proposed gene-disease associations vary in frequency across populations, but their biological impact on the risk for common diseases may usually be consistent across traditional 'racial' boundaries.
authors.affiliation: Clinical and Molecular Epidemiology Unit, Department of Hygiene and Epidemiology, University of Ioannina School of Medicine, Ioannina 45110, Greece. jioannid@cc.uoi.gr
authors.forename: John P A
authors.initials: JP
authors.lastname: Ioannidis
authors.forename: Evangelia E
authors.initials: EE
authors.lastname: Ntzani
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Trikalinos
mesh_terms: D005787:Gene Frequency; D005819:Genetic Markers / Q000235:genetics; D020022:Genetic Predisposition to Disease; D014644:Genetic Variation; D005826:Genetics, Medical; D006801:Humans; D011110:Polymorphism, Genetic; D044469:Racial Groups / Q000235:genetics*
chemical_list: D005819:Genetic Markers