PSEUDOAUTOSOMAL REGION IN SCHIZOPHRENIA - LINKAGE ANALYSIS OF 7 LOCI BY SIB-PAIR AND LOD-SCORE METHODS

In a previous study, we reported a nonrandom segregation between schiz ophrenia and the pseudoautosomal locus DXYS14 in a sample of 33 sibshi ps. That study has been extended by the addition of 16 new sibships fr om 16 different families. Data from six other loci of the pseudoautoso mal region and of the immediately adjacent part of the X specific regi on have also been analyzed. Two methods of linkage analysis were used: the affected sibling pair (ASP) method and the led-score method. Led- score analyses were performed on the basis of three different models-A , B, and C-all shown to be consistent with the epidemiological data on schizophrenia. No clear evidence for linkage was obtained with any of these models. However, whatever the genetic model and the disease cla ssification, maximum led scores were positive with most of the markers , with the highest scores generally being obtained for the DXYS14 locu s. When the ASP method was used, the earlier finding of nonrandom segr egation between schizophrenia and the DXYS14 locus was still supported in this larger data set, at an increased level of statistical signifi cance. Findings of ASP analyses were not significant for the other loc i. Thus, findings obtained from analyses using the ASP method, but not the led-score method, were consistent with the pseudoautosomal hypoth esis for schizophrenia.