Abstract
Objective: Personality traits have been suggested as potential endophenotypes for Bipolar Disorder (BP). We have previously reported on the heritability of factors in the Five Factor personality model (NEO) in a large sample of pedigrees segregating BP.1 A recent genome-wide linkage scan for bipolar disorder in these families reported BP susceptibility loci at 8q24 and 14q32.2 We subsequently performed a quantitative trait linkage analysis for the five NEO factors in this same set of families.
Methods: The present study utilized data from 3757 individuals from 686 extended pedigrees originally ascertained for having multiplex cases of BP. The majority of subjects also completed assessments using The NEO Personality Inventory, Revised (NEO PI-R). Raw scores for each of the five factors were analyzed for linkage analysis using SOLAR (Sequential Oligogenic Linkage Analysis Routines). All subjects were genotyped using the Illumina HumanLinkage-24 Bead Chip, with an average genetic coverage of 0.67 cM.
Summary of results: Suggestive evidence for linkage was found for neuroticism at 1p11.2 (LOD=2.52), 1p22 (2.26), 6q23.3 (2.32), 16p12 (2.79), 17q11.2 (2.24)), extraversion at 4p15.3 (2.33), agreeableness at 4q31.1 (2.37), 5q34 (2.80), 7q31.1 (2.56), 16q22 (2.52), and conscientiousness at 4q31.1 (2.50). In addition, for the trait of openness, we found significant evidence of linkage to chromosome 3p24.3 (rs336610, LOD=4.75) and suggestive evidence at 1q43 (2.74), 3p26 (2.71), 5q35.1 (3.03), 11q14.3 (2.61), 11q21 (2.30), and 19q13.1 (2.52).
Conclusions: Our findings with regard to genetic loci for NEO personality traits support linkage findings of the openness trait to chromosome 19q13 and the agreeableness trait to 4q31 reported in other population based linkage studies. In terms of the genetics of BP in the Latino population we report a number of additional suggestive loci for personality traits (neuroticism, extraversion, agreeableness, and conscientiousness) not previously identified in linkage analyses for the BP phenotype itself.