LINKAGE STUDY OF A SUSCEPTIBILITY LOCUS FOR SCHIZOPHRENIA IN THE PSEUDOAUTOSOMAL REGION

Several lines of evidence suggest that the sex chromosomes have a role in the expression of schizophrenia. Gender differences in response to treatment, age at onset of illness, and prognosis indicate an influen ce of sex in differential expression of schizophrenia. On the basis of a higher-than-expected concordance for sex among siblings with schizo phrenia, as well as the findings of cytogenetic abnormalities of the s ex chromosomes in some schizophrenia patients, a pseudoautosomal locat ion for a schizophrenia susceptibility locus has been proposed. To tes t this hypothesis, we investigated genetic linkage of the pseudoautoso mal region to schizophrenia in a large Swedish kindred. Using pairwise analyses we tested eight markers spanning the most telomeric region t o the boundary of the sex-specific region. In addition, we used multip oint analysis with five markers spanning the region to test for the pr esence of a schizophrenia susceptibility locus in the pseudoautosomal region. No evidence was found for linkage to schizophrenia under the g iven genetic model: ''autosomal'' dominant, f (penetrance) = 0.72, q ( gene frequency) = 0.02, phenocopies = 0.001.