Linkage analyses of schizophrenia to chromosome 6p24-p22: an attempt to replicate.

The present study evaluates evidence for linkage of schizophrenia to chromosome 6p24-p22. An independent sample of 211 families ascertained on the basis of having an affected sib-pair diagnosed with schizophrenia or schizoaffective disorder was assessed with seventeen polymorphic markers spanning a 37cM region. Linkage analysis was performed with parametric and non-parametric methods to test for cosegregation using 4 models of inheritance. Neither two-point nor multipoint non-parametric analyses reached significance at a level less than 0.01 for any markers examined in the region and lod score analyses were not suggestive of linkage. Based on initial findings in the present data set and recently published linkage results, two specific areas were densely covered with markers and tested for linkage disequilibrium. After correcting for multiple comparisons within each locus, no significant deviation from expected allele transmission ratios was observed. The present findings together with the published literature fail to find consistent evidence of a linkage for schizophrenia to a single locus on chromosome 6.