Schizophrenia hippocampus has elevated expression of chondrex glycoprotein gene.

To identify genes associated with schizophrenia, DNA microarray chips were used to compare schizophrenia and control hippocampus tissues, revealing four genes with elevated expression, chondrex (or YKL-40), histamine-releasing factor, HERC2, and heat-shock 70. However, using the quantitative real-time polymerase chain reaction method, only the expression of the chondrex gene, an extracellular matrix glycoprotein involved in cell growth and migration, was found to be significantly elevated, by 1.8-fold. Real-time PCR found that the expression of the histamine-releasing factor gene, known to be associated with cognitive deficits in Alzheimer's disease, was significantly reduced by 19%. The expression of the HERC2 and heat-shock 70 genes, as measured by real-time PCR, were not significantly altered in the schizophrenia hippocampus. The altered gene expression of chondrex suggests that disruption in neuronal migration may be involved in schizophrenia. The change in expression of the histamine-releasing factor gene suggests that this gene may be associated with the negative symptoms of impaired learning and memory in schizophrenia. Copyright 2003 Wiley-Liss, Inc.