[Phenotype-based genetic association studies (PGAS): a new approach to understanding the genotype contribution to...

Schizophrenias are diagnosed purely clinically. The biological basis for this clinical entity is still fully unknown. Genetic studies have revealed some interesting hints but have not led to the identification of actual disease genotypes. On the contrary, it has become more and more probable that widely differing genotype constellations together with manifold environmental factors can trigger schizophrenia according to the motto "many roads lead to Rome...". Thus, new strategies that allow a better insight into complex genotype-phenotype relationships, e. g. PGAS (phenotype-based genetic associations studies) are urgently needed. PGAS became possible on the basis of the GRAS data collection, the as yet largest worldwide phenotypical databank of schizophrenic patients. First PGAS proof-of-concept results on cognition or development-relevant genes are already available.