An examination of linkage of schizophrenia and schizoaffective disorder to the pseudoautosomal region (Xp22.3).

We investigated linkage between schizophrenia and the loci DXYS14, DXYS17, and MIC2 within the pseudoautosomal region in 85 families with two or more siblings suffering from schizophrenia or schizoaffective disorder. A maximum lod score of 2.44 was reached at MIC2, with a dominant model of inheritance at a recombination fraction of 0.

Schizophrenia and sex chromosome anomalies.

An apparent excess of sex chromosome aneuploidies (XXY, XXX, and possibly XYY) has been reported in populations of patients with schizophrenia by a number of authors. These reports have received little attention because transmission of psychosis is regarded as autosomal and not sex linked, and the detection of extra X chromosomes by Barr body estimation alone is not a reliable procedure. In this article, we review studies in which either complete karyotypes were determined for the whole sample or in which the presence of a Barr body in an individual was checked by full cytogenetic analysis.

Male siblings with schizophrenia share alleles at the androgen receptor above chance expectation.

In families that included two or more siblings with schizophrenia or schizo-affective disorder male-male pairs were found to share alleles at the androgen receptor (AR) gene (in Xq11.2-q12) above chance expectation (p < 0.003); female-female and mixed sex pairs showed no such tendency.