Monoamine Oxidase A (MAOA) Gene and Personality Traits from Late Adolescence through Early Adulthood: A Latent Variable Investigation.

Abstract

31 Very few molecular genetic studies of personality traits have used longitudinal phenotypic 32 data, therefore molecular basis for developmental change and stability of personality remains 33 to be explored. We examined the role of the monoamine oxidase A gene (MAOA) on 34 extraversion and neuroticism from adolescence to adulthood, using modern latent variable 35 methods. A sample of 1160 male and 1180 female participants with complete genotyping data 36 was drawn from a British national birth cohort, the MRC National Survey of Health and 37 Development (NSHD). The predictor variable was based on a latent variable representing 38 genetic variations of the MAOA gene measured by three SNPs (rs3788862, rs5906957, and 39 rs979606). Latent phenotype variables were constructed using psychometric methods to 40 represent cross-sectional and longitudinal phenotypes of extraversion and neuroticism 41 measured at ages 16 and 26. In males, the MAOA genetic latent variable (AAG) was 42 associated with lower extraversion score at age 16 (β=-0.167; CI: -0.289, -0.045; p=0.007, 43 FDRp = 0.042), as well as greater increase in extraversion score from 16 to 26 years (β=0.197; 44 CI: 0.067, 0.328; p= 0.003, FDRp = 0.036). No genetic association was found for neuroticism 45 after adjustment for multiple testing. Although we did not find statistically significant 46 associations after multiple testing correction in females, this result needs to be interpreted 47 with caution due to issues related to x-inactivation in females. The latent variable method is 48 an effective way of modelling phenotype- and genetic-based variances and may therefore 49 improve the methodology of molecular genetic studies of complex psychological traits.