ANALYSIS OF CHROMOSOME-18 DNA MARKERS IN MULTIPLEX PEDIGREES WITH MANIC-DEPRESSION

Six pedigrees segregating manic-depressive illness (MDI) were analyzed for linkage to 21 highly polymorphic microsatellite DNA markers on ch romosome 18. These markers span almost the entire length of the chromo some, and gaps between markers ave less than 20 cM. In particular, we analyzed several markers localizing to the pericentromeric region of c hromosome 18 which generated lod scores suggestive of linkage in an in dependent study. Lod score analysis was performed and results were exa mined by family, One region produced positive lod scores, though at 18 q23 and not in the pericentromeric region. We additionally used two no nparametric methods because the true mode of transmission of MDI is un known; results were again somewhat suggestive for markers in the regio n of 18q23 but not in the pericentromeric region.