[Genetics of schizophrenia]

Schizophrenia is a complex disease. Although family, twin and adoption studies have consistently suggested that genetic factors play an important etiologic role in schizophrenia, very little is known about the nature and number of these genetic factors. The familial transmission of this disorder cannot be explained by simple Mendelian models of inheritance, and non-genetic factors are also likely to play a substantial role in its aetiology. The current hypothesis is that genes with small interacting genetic effects, in conjunction with environmental factors, affect the risk for schizophrenia. But the relationship between observed genetic factors and specific DNA variants or protein alterations has not so far been identified. Classical methods, such as linkage or association studies, have led to inconsistent results. Other options such as the endophenotype strategy or the use of chromosomal aberrations associated with psychotic symptoms are probably more promising to identify candidate genes.