Replication of 1q42 linkage in Finnish schizophrenia pedigrees.

Chromosome 1q has been implicated in the etiology of schizophrenia in several independent studies. However, the peak linkage findings have been dispersed over a large chromosomal region, with negative findings in this region also being reported. Our group has previously observed linkage on chromosome 1q42, maximizing within the DISC1 gene, which has also been implied in the etiology of schizophrenia based on functional studies. In the study presented here, we genotyped 300 polymorphic markers on chromosome 1 using a study sample of 70 families with multiple individuals affected with schizophrenia or related conditions, independent of the study samples in our previous reports. We again found evidence for linkage on 1q42 maximizing within the DISC1 gene (rs1000731, lod=2.70). Further, a haplotype containing the most strongly linked markers showed some evidence of association with the disease. This replicates the previous linkage finding in the same region and constitutes supportive evidence for a susceptibility gene in this region.