The Genetics of Schizophrenia

Summary

On the basis of findings from family, twin, and adoption studies, heredity emerges as a major etiological factor in the pathogenesis of schizophrenia. Molecular genetic techniques (mainly genetic association and linkage studies) indicate that area 13q32 on chromosome 13 and, possibly, areas 6p24–22, 6q16–24, 8p, and 22q11–13, as well as the gene of serotonin 2A receptor, may be implicated in the pathogenesis of schizophrenia. As yet, however, no major genes have been identified; this is mainly because of the assumed heterogeneity of the disease, multigenic inheritance, reduced penetrance of genotype(s), and interplay between genetic and environmental vulnerability factors. Identification of genetically homogeneous patient subgroups and carriers of genes with reduced penetrance is based on “soft” neurological signs; deficits in auditory sensory gating and smooth pursuit eye movements; neuroanatomical abnormalities; deviant patterns of cerebral regional blood flow, functional MRI and brain lateralization; and biochemical indices of neurotransmitter abnormalities. The integration of molecular genetics with other fields of neuropsychiatry could provide new advances in our understanding of the interactions among the various genetic and environmental mechanisms leading to schizophrenia and allow the implementation of accurate genetic counseling and more appropriate interventions for the prevention and management of this devastating disease.