A DTI study of white matter microstructure in individuals at high genetic risk for schizophrenia.

Structural brain developmental anomalies, particularly those in frontotemporal white matter pathways, may have a genetic component and place people at increased risk for schizophrenia. The current study employed Diffusion Tensor Imaging (DTI) to measure fractional anisotropy (FA) as a quantitative indicator of white matter integrity. We examined twenty-two participants at high genetic risk for schizophrenia (HR), 23 people with schizophrenia (most of whom were family members of those at HR) and 37 non-psychiatric controls for comparison. In those at HR, reduced FA was observed in the cingulate and angular gyri bilaterally. In a few regions, FA was higher in HR participants than in comparison participants. These regional variations in FA might reflect differences in white matter development from comparison participants. Our data provide some evidence that abnormal white matter integrity may be detectable before the onset of a psychotic illness, although longitudinal studies are necessary to determine whether these individuals at genetic risk with abnormal FA will develop illness and whether these changes are associated with the genetic risk for the disorder.