Abstract
Chromosome 8p21β12 has been reported to be a susceptibility locus for schizophrenia based on genomeβwide linkage scans. After neuregulin 1 (NRG1) was identified as a positional candidate gene for schizophrenia in this locus, several independent association studies have reported controversial results. To determine whether genetic variations in this locus are associated with schizophrenia in the Korean population, we investigated multiplex families and unrelated patients using linkage and association analyses. Seven microsatellite markers in 8p21β12 were genotyped for 40 families with schizophrenia, and a nonβparametric linkage analysis was applied. The association study was performed with 242 unrelated schizophrenia patients and the same number of normal controls for three single nucleotide polymorphisms (SNPs), two microsatellite markers and their haplotypes. A significant linkage signal was observed on D8S1769, which is located 352 kb upstream of the 5β² end of the first exon of NRG1 for two (βnarrowβ and βnarrow with auditory hallucination (AH)β) of the three adopted phenotype classes. In the association study, the G allele of SNP8NRG241930 was significantly in excess in the subgroup of patients with AHs. We also found haplotypes which were associated with schizophrenia with a protective effect. This study provides additional suggestive evidence for both the linkage and association of genetic variations on 8p12, a locus of NRG1, with schizophrenia. NRG1 might either play a role in the predisposition to schizophrenia or be in linkage disequilibrium (LD) with a causal locus of this illness. Β© 2006 WileyβLiss, Inc.