A linkage study of affective disorder with DNA markers for the ABO-AK1-ORM linkage group near the dopamine beta hydroxylase gene.

Combining data from a number of studies has provided evidence for a susceptibility allele for affective disorder near to the ABO-AK1-ORM region on chromosome 9q34. The dopamine beta hydroxylase gene locus is also at 9q34. Five multigenerational families with bipolar and unipolar affective disorder were analyzed for linkage with highly polymorphic microsatellite markers from the candidate region. The segregation of the illness in these families was compatible with an autosomal dominant susceptibility allele. Linkage analyses using conservative parameters seemed to provide strong evidence against a major susceptibility allele in this region including the candidate gene dopamine beta hydroxylase in these families.