Brief reportQuantitation of X-Y homologous genes in patients with schizophrenia by multiplex polymerase chain reactionRoss, Norman L. J.a; Mavrogiannis, Lampros A.b; Sargent, Carole A.c; Knight, Samantha J. L.b; Wadekar, Rekhaa; DeLisi, Lynn E.d; Crow, Timothy J.aAuthor Information aUniversity of Oxford, Department of Psychiatry, Warneford Hospital, Oxford, UK, bWeatherall Institute of Molecular Medicine, John Radcliffe Hospital, Oxford, UK, cHuman Molecular Genetics Group, University of Cambridge, Department of Pathology, Cambridge, UK and dNY University School of Medicine, Mill Hauser Laboratories, New York, USA. Sponsorship: The following authors received financial support for their work from the institutions stated. Timothy Crow, MRC and the Stanley Foundation; Norman Ross, Stanley Foundation; Rekha Wadekar, SANE. Correspondence to Norman L. J. Ross, University of Oxford, Department of Psychiatry, Warneford Hospital, Headington, Oxford OX3 7JX, UK. Tel: + 44 1865 226484; fax: + 44 1865 244990; e-mail: [email protected] Received 3 July 2002 Accepted 5 August 2002 Psychiatric Genetics: June 2003 - Volume 13 - Issue 2 - p 115-119 doi: 10.1097/01.ypg.0000056683.89558.1c Buy Metrics Abstract Objectives The genetic basis of schizophrenia is obscure. In an XX male patient with schizophrenia we previously showed that one X;Y translocation breakpoint was in pseudoautosomal region 1 (PAR1) with the effect that the proximal segment of PAR1 from the PAR1 boundary to acetylserotonin N-methyl transferase (ASMT) distally was triplicated in this patient. This study determined whether dosage imbalances of X-Y homologous regions in general are associated with schizophrenia. Methods A multiplex semi-quantitative polymerase chain reaction assay was developed to quantifyMIC2gene as a representative of PAR1 and compare it with theSYBL1gene which maps in pseudoautosomal region 2 (PAR2) and protocadherin XY (PCDHXY), located at Xq21.3. Each of these three loci was co-amplified with the autosomal geneMSX2using Cy5-labelled primers and the products separated by electrophoresis in polyacrylamide gels. Results were expressed as ratios of peak area of the target gene toMSX2which served as an internal dosage control. Results Using genomes with sex chromosome aneuploidies, the method was found sensitive enough to detect a two-fold difference in gene copy number. We confirmed theMIC2triplication in the XX male patient but found no significant difference in gene dosage ofMIC2, PCDHXYandSYBL1in a panel of 17 patients with schizophrenia compared to controls. Conclusions No evidence was obtained for gene dosage imbalances inMIC2, PCDHXYandSYBL1in patients with schizophrenia. Psychiatr Genet 13:115–119 © 2003 Lippincott Williams & Wilkins. © 2003 Lippincott Williams & Wilkins, Inc.