Disorder specificity of gray and white matter endophenotypes

Genetic risk for bipolar disorder was not significantly associated withvolume deficits in the gray matter endophenotype for schizophrenia, and therewas a significant interaction between the 2 relative groups (relatives ofpatients with schizophrenia vs relatives of patients with bipolar disorder)and genetic liability on PC scores (Table 3 and Figure 1B). These results indicate that graymatter variation in this distributed frontostriatal and temporal system isan endophenotypic marker specifically associated with genetic risk for schizophrenia.

Likewise, genetic risk for schizophrenia was not significantly associatedwith volume deficits in the gray matter endophenotype for bipolar disorder,and there was a significant interaction between the 2 relative groups (relativesof patients with schizophrenia vs relatives of patients with bipolar disorder)and genetic liability on PC scores (Table 3 and Figure 1C). These results indicate that graymatter variation in this relatively circumscribed cingulate and striatal systemis an endophenotypic marker specifically associated with genetic risk forbipolar disorder.

Genetic liability for bipolar disorder was associated with anatomicaldeficits in the white matter endophenotype defined by univariate analysisof the schizophrenia group; similarly, genetic liability for schizophreniawas associated with anatomical deficits in the white matter endophenotypedefined by analysis of the bipolar disorder group (Table 3). A finer-grained analysis of genetic risk and endophenotypicassociation for the white matter systems showed that genetic liability scorewas generally associated with variation in the left hemispheric parts of bothschizophrenia and bipolar disorder endophenotypes (Figure 2C) but that genetic risk for bipolar disorder was specificallyassociated with the right hemispheric parts of the bipolar disorder whitematter endophenoype (further details are available from us on request). Therewas no material change in the results of the analyses of the combined relativesgroup after excluding the 24 relatives who had a previous diagnosis of anyAxis 1 disorder, schizotypal personality disorder, or alcohol or substancedependence or were taking any psychotropic medications. These results indicatethat white matter variation in the left frontal and temporoparietal regionsis an endophenotypic marker generically associated with genetic risk for bothschizophrenia and bipolar disorder.

Дата добавления: 2015-08-17