Cerebral ventricle-brain ratio in monozygotic twins discordant and concordant for schizophrenia

1. Several studies on monozygotic twins discordant for schizophrenia showed that the cerebral ventricle-brain ratio (VBR) was larger in the twins with schizophrenia, as compared with the corresponding normal twins. 2. The results suggest that the difference of the VBR of the discordant twins was larger than that of the concordant twins of schizophrenia. 3. The authors studied the VBR in four monozygotic twin pairs discordant and four monozygotic twin pairs concordant for schizophrenia by computerized tomography. 4. In the discordant twins, all pairs showed that the VBR of the normal twins was smaller than that of the corresponding twins with schizophrenia. 5. The difference of the VBR of the discordant twins and that of the concordant twins of schizophrenia was not statistically different using Mann-Whitney U test. 6. The preliminary results suggest that the VBR enlargement in schizophrenia is not genetically controlled in monozygotic twins either discordant or concordant for schizophrenia. 7. In monozygotic concordant twins, the brain pathology may be heterogeneous.