Brief ReportCopy Number Variation in Schizophrenia in the Japanese Population
Section snippets
Methods and Materials
We analyzed 1139 age- and gender-matched unrelated subjects of Japanese ethnicity (575 schizophrenic patients and 564 control subjects). Control subjects were members of the general public who had no personal history of mental disorders. This was ascertained during face-to-face interviews where subjects were asked if they had suffered an episode of depression, mania, or psychotic experiences or if they had received treatment for any psychiatric disorder. Patients were entered into the study if
Results
The numbers of rare CNVs stratified by size in cases and control subjects are listed in Table 1. Overall, we found an excess of CNVs in subjects with schizophrenia (case-control ratio = 1.16). Although not significant (p = .087, one-tailed permutation test), this is similar to that reported by the largest CNV study (4) where the case-control ratio was 1.15. The effect in that study (4) was coming mostly from deletions >500 kb and duplications in the 100 kb to 200 kb range. No subcategory of CNV
Discussion
In this study, we do not find a significant increase in the burden of CNVs in schizophrenia, either overall or for any specific size range of CNVs, as proposed in previous studies (2, 3, 4, 7). We did, however, find several trends in the same direction and of a similar magnitude as the largest global CNV survey of schizophrenia (4). Not all research has found such an increased burden, e.g., no evidence was obtained from a study in the Chinese population (5). It is possible that genuine
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