Schizophrenia genetic factors

Research into the risk factors for Cluster A personality disorders has focused on genetic factors. In particular, many researchers have looked for a shared genetic linkage between these disorders and schizophrenia. Only schizotypal personality appears to be genetically linked to schizophrenia. It may be that STPD exists on a biological continuum with schizophrenia. In other words, STPD could theoretically be a far milder variant of Axis I schizophrenia. There is less evidence linking PPD or SPD to schizophrenia nevertheless, certain characteristic symptoms of these other disorders also overlap with schizophrenia. 

Genetic factors are important in the pathogenesis of schizophrenia (Karayiorgou and Gogos, 1997), and the notion that such factors may be more salient in very early onset-cases fueled two classic family studies of childhood-onset cases (Kallmann and Roth, 1956 Kelvin et al., 1971). 

Environmental factors, such as prenatal maternal infections and perinatal complications, have been implicated in the pathogenesis of schizophrenia. Also, the correlation of only 0.6 for age of onset in monozygotic twins concordant for schizophrenia suggests that non-genetic factors play a role in determining the age of onset (Kendler et ah, 1987). A greater frequency or severity of these factors could conceivably result in an earlier onset of schizophrenia. 

The exact cause of schizophrenia has been the subject of extensive research. It appears that genetic factors (i.e., chromosomal abnormalities that cause deviations in brain structure and function) are the primary risk factors in the majority of people with schizophrenia (70% to 80%).15,23 Environmental factors (social stresses, prenatal or childhood brain injury, and so forth) seem to be the underlying cause in the remaining 20% to 30% of people with schizophrenia.23 The precise role of these factors, and the interplay between genetic and environmental factors, continues to be elucidated.28,50 61... 

In order to facilitate detection of genetic factors linked to schizophrenia, Kenneth Kendler and Dermot Walsh recruited members of families in Ireland with a history of the disorder (Kendler et al., 1996). The field... 

We propose that a redox/antioxidant dysregulation due to GSH deficit could represent a vulnerability factor at the early phase of brain development in at least a subgroup of schizophrenia patients. Combined with other genetic factors and environmental factors, such as stress, obstetrical complications or viral infections, it could favor the development of the disease. The role of the GSH deficit proposed allows integration in a causal way many phenomenological aspects of schizophrenia. It is compatible with both the DA and the glutamate/NMDA hypotheses and with the neuropathological observations. In contrast to... 

Ujike H, Nomura A, Morita Y, Morio A, Okahisa Y, Kotaka T et al (2008) Multiple genetic factors in olanzapine-induced weight gain in schizophrenia patients a cohort study. J Clin Psychiatry 69 1416-1422... 

Millar JK, Pickard BS, Mackie S et al (2005) DISCI and PDE4B are interacting genetic factors in schizophrenia that regulate cAMP signaling. Science 310 1187-1191... 

A neurobioiogicai basis for schizophrenia and reiated psychotic syndromes remains eiusive. Compeiiing evidence iinking genetic factors to the etioiogy of schizophrenia is not apparent despite enormous progress in ... 

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