Our findings highlighted that white matter abnormalities were present by the time of remission of first-episode mania. The widespread occurrence of these white matter abnormalities both in first-episode mania and chronic bipolar disorder suggested that disruption of white matter cortical-subcortical networks as well as projection, associative, and commissural tracts is a hallmark of the illness.

Genome-wide association, case association genetic and meta-analytic studies have highlighted ZNF804A as a robust genome-wide supported susceptibility gene for schizophrenia (SCZ). In view of the possible involvement of ZNF804A gene in early neurodevelopment and cellular processes including oligodendrocyte proliferation and differentiation, we examined the effect of ZNF804A on brain WM (WM) integrity in patients with SCZ. Based on extant data in healthy controls (HC), we hypothesized that ZNF804A risk variant rs1344706 is associated with lower fractional anisotropy (FA) in brain regions within cortico-limbic circuits, namely frontal, parietal, medial temporal lobes, and cingulate gyri in SCZ. A total of 200 Chinese participants (125 patients with DSM-IV diagnosis of SCZ and 75 controls) were genotyped using blood samples, a subset of 153 participants (89 patients with DSM-IV diagnosis of SCZ and 64 controls) underwent structural magnetic resonance imaging and diffusion tensor imaging (DTI). There are significant effects of diagnosis (left cingulate gyrus: Adjusted F(1,149)  = 9.36, P = 0.003) and diagnosis-genotype interactions (left parietal lobe: Adjusted F(1,147)  = 7.39, P = 0.007; right parietal lobe: Adjusted F(1,147)  = 6.95, P = 0.009; right medial temporal lobe: Adjusted F(1,147)  = 8.79, P = 0.004; left cingulate gyrus: Adjusted F(1,147)  = 8.02, P = 0.005). Specifically, we found that patients with SCZ who are risk T homozygotes have lower FA in bilateral parietal lobes, and left cingulate gyrus compared with G carriers. Compared with risk T homozygotes in HC, patients with SCZ who are risk T homozygotes have decreased FA in bilateral parietal lobes, and left cingulate gyrus as well as right medial temporal lobe. Our findings suggest that ZNF804A risk variant influence WM integrity involving cortico-limbic brain regions in SCZ and highlight the importance of investigating the impact of genome-wide supported risk factors on intermediate phenotypes with potential to shed light on the neurobiology of SCZ.

These findings are consistent with known ARVCF gene effects on neurodevelopment in terms of cellular arrangement, migration, and intracellular signaling involving the striatum and may involve interactions with other brain networks such as prefrontal cortex, and they underscore the importance of imaging-genetic studies to elucidate the genetic influences underlying intermediate phenotypes in complex neurobehavioral disorders.