Genetic Dissection of Temperament Personality Traits in Italian Isolates.

Human personality (i.e., temperament and character) is a complex trait related to mental health, influenced by genetic and environmental factors. Despite the efforts performed during the past decades, its genetic background is only just beginning to be identified. With the aim of dissecting the genetic basis of temperament, we performed a Genome-Wide Association Study (GWAS) on Cloninger's Temperament and Character Inventory in 587 individuals belonging to different Italian genetic isolates. Data analysis led to the identification of four new genes associated with different temperament scales, such as Novelty Seeking (NS), Harm Avoidance (HA), and Reward Dependence (RD). In detail, we identified suggestive and significant associations between: MAGI2 (highest p-value = 9.14 × 10-8), a gene already associated with schizophrenia and depressive disorder, and the NS-Extravagance scale; CALCB (highest p-value = 4.34 × 10-6), a gene likely involved in the behavioral evolution from wild wolf to domestic dog, and the NS-Disorderliness scale; BTBD3 (highest p-value = 2.152 × 10-8), a gene already linked to obsessive-compulsive disorder, and the HA-Fatigability scale; PRKN (highest p-value = 8.27 × 10-9), a gene described for early onset Parkinson's disease, and the RD scale. Our work provides new relevant insights into the genetics of temperament, helping to elucidate the molecular basis of psychiatric disorders.