Dissecting the genetic complexity of schizophrenia.

Twin, adoption and family studies have provided overwhelming but indirect evidence for a significant genetic contribution to the etiology of schizophrenia. More recent studies exploiting a plethora of highly polymorphic genetic markers provide a more direct approach to the identification and localization of genes. Current investigative efforts to identify schizophrenia susceptibility genes include diverse approaches such as linkage analysis, association studies, search for chromosomal abnormalities, analysis of disorders or syndromes with simple inheritance that overlap phenotypically with schizophrenia, studies of genetic anticipation and efforts to facilitate genetic analysis by reducing the phenotypic complexity of the disease. For the first time, after many years, there are now several promising findings, as well as replication efforts that inspire a certain degree of confidence in them.