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Disease Markers
Volume 21 (2005), Issue 2, Pages 61-69

Over-Expression of Dopamine D2 Receptor and Inwardly Rectifying Potassium Channel Genes in Drug-Naive Schizophrenic Peripheral Blood Lymphocytes as Potential Diagnostic Markers

Ágnes Zvara,1 György Szekeres,2 Zoltán Janka,2 János Z. Kelemen,1 Csongor Cimmer,2 Miklós Sántha,3 and László G. Puskás1

1Laboratory of Functional Genomics, Biological Research Center, Hungarian Academy of Sciences, Szeged, Temesvári krt. 62., H- 6726, Hungary
2Department of Psychiatry, Albert Szent-Györgyi Center for Medical and Pharmaceutical Sciences, Faculty of Medicine, University of Szeged, Szeged, Semmelweis u. 6., H-6725, Hungary
3Laboratory of Molecular Neurobiology, Institute of Biochemistry, Biological Research Center, Hungarian Academy of Sciences, Szeged, Temesvári krt. 62., H-6726, Hungary

Received 24 May 2005; Accepted 24 May 2005

Copyright © 2005 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Schizophrenia is one of the most common neuropsychiatric disorders affecting nearly 1% of the human population. Current diagnosis of schizophrenia is based on complex clinical symptoms. The use of easily detectable peripheral molecular markers could substantially help the diagnosis of psychiatric disorders. Recent studies showed that peripheral blood lymphocytes (PBL) express subtypes of D1 and D2 subclasses of dopamine receptors. Recently, dopamine receptor D3 (DRD3) was found to be over-expressed in schizophrenic PBL and proposed to be a diagnostic and follow-up marker for schizophrenia. In this study we screened PBL of 13 drug-naive/drug-free schizophrenic patients to identify additional markers of schizophrenia. One of the benefits of our study is the use of blood samples of non-medicated, drug-naive patients. This excludes the possibility that changes detected in gene expression levels might be attributed to the medication rather than to the disorder itself. Among others, genes for dopamine receptor D2 (DRD2) and the inwardly rectifying potassium channel (Kir2.3) were found to be over-expressed in microarray analysis. Increased mRNA levels were confirmed by quantitative real-time PCR (QRT-PCR) using the SybrGreen method and dual labeled TaqMan probes. The use of both molecular markers allows a more rapid and precise prediction of schizophrenia and might help find the optimal medication for schizophrenic patients.