SU48 - HERITABILITY OF HAIR CORTISOL AND GENETIC OVERLAP WITH PSYCHOLOGICAL VARIABLES

Abstract

Background Measuring cortisol in hair is a promising method to assess the regulation of the Hypothalamus-Pituitary-Adrenal (HPA) axis which is altered in psychiatric disorders. First studies indicate a contribution of genetic factors to inter-individual variance in Hair Cortisol Concentration (HCC). Evidence for a genetic overlap between HCC and psychological variables would indicate a true biological link pointing at a causal involvement of the HPA axis in the vulnerability for psychiatric disorders. The aims of the present study were (1) to assess the heritability of HCC (2) to estimate the genetic and environmental association of HCC and perceived stress, depressive symptoms and neuroticism using twin models and a molecular genetic approach, i.e. Polygenic Risk Scores (PRS). Methods Hair samples from 671 individuals (mean age=14.5 years) including 183 dizygotic twin-pairs were analyzed. PRS scores were based on large published genome-wide association studies for depression, neuroticism and plasma cortisol, and analyzed in 432 individuals. Results The twin model revealed (1) a heritability of HCC of 72%, but (2) no phenotypic nor genetic overlap of HCC with psychological variables. Discussion HCC is highly heritable, but shows no phenotypic / genetic correlation with any of the studied psychological variables in our young individuals from the general population.