GENETIC ASSOCIATION BETWEEN MONOAMINE-OXIDASE AND MANIC-DEPRESSIVE ILLNESS - COMPARISON OF RELATIVE RISK AND HAPLOTYPE RELATIVE RISK DATA

There have been several conflicting reports of association of monoamin e oxidase (MAO) A gene polymorphisms and bipolar affective disorder, I n order to determine the possible role of the MAO region in susceptibi lity to affective disorders in an independent sample, we have genotype d 83 probands of bipolar affective disorder families, 56 sets of paren ts of bipolar probands, and 84 normal controls for intronic simple seq uence repeat polymorphisms of the MAO-A and MAO-B genes, For MAO-A the re were no significant differences in allele frequencies between bipol ar and normal control groups for both genders, However, for MAO-B ther e were significant differences between groups for both genders, In con trast, allele-wise haplotype relative risk analysis for the 56 bipolar proband-parent trios found no significant differences between transmi tted and nontransmitted allele frequencies for MAO-A or B, These data do not support the association of MAO-A or B with bipolar affective di sorder but do demonstrate that undetected population stratification ca n be an important source of bias in case-control studies, (C) 1997 Wil ey-Liss, Inc.