Brief report Interleukin-1 receptor antagonist genotype and brain morphometry in first-episode non-affective psychosis Roberto Roiz-Santiáñez a , Benedicto Crespo-Facorro a, ⁎ , Rocío Pérez-Iglesias a , José María Pelayo-Terán a , Eugenio Carrasco-Marín b , Ignacio Mata a , Elena Sánchez c , Francisco Leyva-Cobián b , José Luis Vázquez-Barquero a a University Hospital Marqués de Valdecilla, Department of Psychiatry. School of Medicine, University of Cantabria., Santander, Spain b University Hospital Marqués de Valdecilla, Department of Immunology, Santander, Spain c University Hospital Marqués de Valdecilla, Department of Neuroradiology, Santander, Spain Received 18 April 2007; received in revised form 18 July 2007; accepted 10 October 2007 Abstract Studies of schizophrenia that combine imaging and genetic approaches attempt to map structural brain anomalies associated with genetic risk variants. The aim of the present study was to investigate whether variations in the interleukin-1 receptor antagonist (IL- 1RN) were associated with structural brain characteristics of 73 minimally medicated first-episode non-affective psychotic patients. We did not find evidence for association between genetic variation in the IL-1RN gene and brain morphometry at early phases of the illness. © 2007 Elsevier Ireland Ltd. All rights reserved. Keywords: Structural neuroimaging; MRI; Brain morphometry; Schizophrenia; Gene; Interleukin-1 receptor antagonist genotype 1. Introduction Schizophrenia is a brain disorder that shows a high genetic heritability involving multiple genes (Sullivan et al., 2003). However, the biological consequences of these genetic components remain elusive. Understand- ing the neural mechanisms (intermediate phenotypes) by which genetic variations are associated with disease phenotype represents an appealing strategy for research in the field (Meyer-Lindenberg et al., 2006). Imaging genetic studies in schizophrenia attempt to map struc- tural and functional brain anomalies associated with ge- netic risk variants (Callicott et al., 2005). The interleukin-1 receptor antagonist (IL-1RN) gene maps on chromosome 2q.14.2, a region with evidence of linkage to schizophrenia (Lewis et al., 2003). A VNTR polymorphism, consisting of two to six repeats of a 86- bp core sequence, has been located within intron 2 of the gene (Tarlow et al., 1993). Variations in this polymor- phism have been reported to increase the risk for schizophrenia (Katila et al., 1999), to predict improve- ment in negative symptoms in first-episode patients (Mata et al., 2006), and to mediate ventricular enlarge- ment in a sample of mostly chronic and medicated schizophrenia subjects (Papiol et al., 2005). Imaging genetic studies at illness onset are of special relevance since the effects of confounding factors (such as Available online at www.sciencedirect.com Psychiatry Research: Neuroimaging 162 (2008) 167 – 171 www.elsevier.com/locate/psychresns ⁎ Corresponding author. Hospital Universitario Marqués de Valde- cilla. Department of Psychiatry, Planta 2 a , Edificio 2 de Noviembre. Avda. Valdecilla s/n, 39008, Santander, Spain. Tel.: +34 942 202537; fax: +34 942 203447. E-mail address: bcfacorro@humv.es (B. Crespo-Facorro). 0925-4927/$ - see front matter © 2007 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.pscychresns.2007.10.001