Significant linkage to chromosome 22q for exploratory eye movement dysfunction in schizophrenia

A genome-wide scan for a locus responsible for exploratory eye movement (EEM), which is quantitative and can be disturbed in association with schizophrenia, was performed. A 10-cM resolution genome-wide linkage analysis of the EEM disturbance with 358 highly polymorphic microsatellite markers in 38 nuclear families with 122 members (38 probands, 47 sibs, and 37 parents) including 58 sib-pairs yielded the suggestive linkage to the GCT10C10 marker on chromosome 22q11.2 (LOD = 2.48). Dense mapping with additional markers around the GCT10C10 marker yielded evidence for significant linkage between EEM disturbance and markers D22S429 and D22S310 on chromosome 22q12.1 (LOD score of 4.63) with suggestive evidence for the chromosome region 22q11.2-q12.1. Our findings suggest that a relatively small number of loci may control the schizophrenia-related quantitative EEM trait. We believe that identifying gene(s) on chromosome 22q associated with the EEM phenotype may forward our understanding of the etiology of schizophrenia.