From age correction to genome-wide association

Objective: Eric Stromgren was one of the pioneers of psychiatric genetics and family studies. There has now been an explosion of interest in this field and research progress, including linkage and association studies, whole genome genotyping, copy number variants and epigenetics is reviewed here. Method: An overview of this area of psychiatric research is presented and discussed based on the relevant literature aiming at giving a recent status of the progress. Results: Broadly speaking linkage and association are complementary approaches used to locate genes contributing to the genetic aetiology of psychopathology. Linkage can be detected over comparatively large distances, however power is problematic when searching for quantitative trait loci with small effect sizes. In contrast, association studies can detect small effects but only over very small distances. Therefore, while several genome-wide linkage studies in psychiatric disorders have been performed, the majority of association studies have investigated specific functional candidate genes. Conclusion: Due to very recent technological advancements, genome-wide association studies have now become possible and have identified some completely novel susceptibility loci. Other recent advances include the discovery of epigenetic phenomena and copy number variants.