Association of NEO-PI Neuroticism and Extraversion with SNPs from the Dopaminergic System
Kokoszka, Noah A.
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The success of genetic studies in the area of mental health has been greatly limited by the complexity of psychiatric diseases. Therefore, a method that involves examining personality traits (endophenotypes) as risk factors that are correlated with psychiatric disorders is being implemented. Personality, a person’s thoughts, feelings and behaviors, is of particular interest to mental health researchers. Extreme scores on personality tests can often be risk factors of various mental health disorders. Mental health disorders, for the purposes of this study, are viewed at as phenotypes. In this study, each of these phenotypes has several components known as endophenotypes. For example, bipolar disorder (phenotype) consists of anxiety, depression, and positive emotions (endophenotypes). Due to scientific findings that suggest a strong relationship between an individual’s personality and their genetics, these endophenotypes can serve as biomarkers that link a phenotype with a SNP (Single Nucleotide Polymorphism) if the association between the endophenotypes and SNP is strong enough. The endophenotypes used in this study are facets from two domains, Extraversion and Neuroticism, of the Neuroticism- Extraversion-Openness Personality Inventory (NEO-PI) personality test.In this study, blood samples were taken and the NEO-PI personality test was administered to 903 participants. After the participants had their genomes sequenced, 64 SNPs of the Dopamine system from six genes (DBH, DRD1, DRD2, DRD3, DRD4 and SLC6A3) were examined in order to find any associations between SNPs of the Dopamine system and the NEOPI personality traits of Neuroticism and Extraversion. SNP rs6350 and rs11747728 were both found to be significantly associated with Neuroticism. In addition, it was found that rs11747728 not only had a significant association with Extraversion, but that the significance of its association was so strong that it passed correction for multiple testing. Since this finding has not een reported before, more tests must be done in order to solidify the validity of this result. Future directions include documenting associations between mental illnesses and endophenotypes, and determining the functional significance (if any) that rs11747728 has on its corresponding protein.