Construction of Balanced Translocation t(1;11)(q42.1;q14.3) Probe and Screening Application in Genomic Samples in Taiwan

The disrupted-in-schizophrenia 1 (DISC1) gene is a candidate gene in schizophrenia. The balanced t(1;11)(q42.1;q14.3) translocation with a breakpoint between exons 8 and 9 of DISC1 has been found to be co-segregated with psychosis in a Scottish family. To examine whether the t(1;11)(q42.1;q14.3) translocation exists in Taiwanese samples, we constructed a plasmid probe that carried the two DNA fragments of chromosome 1 (738 bp) and chromosome 11 (719 bp) that covered the breakpoint. This probe was validated using a derived DNA gift from the translocation carrier of the Scottish family. We screened genomic DNA samples from 619 subjects (507 cases and 112 controls). None of the subjects showed the designed polymerase chain reaction (PCR) product detected by the probe. We concluded that the significant association between schizophrenia and the DISC1 gene in the Taiwanese sample was not caused by balance translocation, but rather by polymorphic variations of the gene to be detected.