Suggestive linkage of schizophrenia to 5p13 in Costa Rica.

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.