1. ¹Department of Biological Chemistry, University of California, Irvine, Irvine, California, USA
2. ²Asociación Centro de Estudios Neuropsiquiátricos de Costa Rica (ACENP de Costa Rica), San José, Costa Rica
3. ³Department of Psychiatry and Human Behavior, University of California, Irvine, Irvine, CA, USA
4. ⁴Hospital Nacional Psiquiátrico, Pavas, Costa Rica

Correspondence: Mrs K Cooper-Casey, Department of Biological Chemistry, University of California Irvine, UCI, Gillespie #837, Room 2216, Irvine, California 92697, USA. E-mail: kmcooper@uci.edu

Received 1 November 2004; Accepted 19 November 2004; Published online 8 February 2005.

Abstract

Schizophrenia afflicts roughly 1% of all people worldwide. Remarkably, despite differing cultures and environments, the expression of illness is essentially the same. Family, twin, and adoption studies identify schizophrenia as a genetically influenced disease. Linkage studies suggest many positive regions of interest, but as a complex genetic disorder most of the pathogenic loci have not yet been found. Isolated populations are commonly used to study rare Mendelian inherited diseases due to the more homogenous genetic background of the subjects and are thought to be useful for detecting linkage in complex genetic disorders such as schizophrenia. This study aims to define areas of the genome that exhibit co-inheritance with schizophrenia in one large, Mendelian-like family from the central valley of Costa Rica. The whole genome scan analysis of this pedigree, which included 11 cases of schizophrenia and schizoaffective disorder, identified a number of markers on chromosome 5p that appear to co-segregate with the disease with a maximum lod score of 2.70 at marker D5S426. Current studies include investigating additional Costa Rican pedigrees to replicate these findings and identify additional loci linked to the disease.