Masters Degrees (Molecular Biology and Human Genetics)

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Browsing Masters Degrees (Molecular Biology and Human Genetics) by Author "Benecke, Rohan Meerholz"

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    Genetic aetiology of anxiety disorders
    (Stellenbosch : Stellenbosch University, 2016-12) Benecke, Rohan Meerholz; Hemmings, Sian; Seedat, Soraya; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Biomedical Sciences: Molecular Biology and Human Genetics.
    ENGLISH SUMMARY: Anxiety disorders are among the most prevalent psychiatric disorders among both adults and adolescents. Comorbidity with other psychiatric disorders, including other anxiety disorders, is common and it is clear that a high degree of burden of distress and impairment is associated with the condition. Substantial evidence has been presented to suggest a strong genetic component in the aetiology of anxiety disorders. Twin and family studies suggest that panic disorder, general anxiety disorder, phobias and obsessive-compulsive disorder (OCD) aggregate in families. Twin studies in particular shown greater intrapair resemblance between monozygotic twins compared to dizygotic twins, suggesting a strong genetic component. Several genes have been implicated in the genetic aetiology of anxiety disorders, the most prominent of which are BDNF and SCL6A4. Furthermore, the role of the HPA axis in the regulation of the normal response to fear and stress may be influenced by genes contributing to cortisol functions such as FKBP5 and CRHR1. The severity of childhood trauma can contribute to the development of anxiety disorders by modulating gene expression. In this study anxiety sensitivity (AS) is investigated as a possible predictive marker for development of anxiety disorders. Adolescents (13-18 years of age) were recruited from senior secondary schools in the Cape Town area of the Western Cape. Participants were subjected to psychological screening, which included the childhood anxiety sensitivity index (CASI) as well as the childhood trauma questionnaire (CTQ), and saliva samples were collected and genotyping conducted. Gene-environment (G × E) interactions, focussing on the severity of childhood trauma and selected genetic variants, were investigated to determine how levels of AS in a South African adolescent population were modulated. Our cohort consisted of predominantly Xhosa and Coloured individuals and analysis was done on both ethnic groups separately. Significant findings in FKBP5 and CRHR1 in males of both ethnic groups suggests sex linked effect in genes regulating cortisol function. The severity of childhood trauma was found to modulate selected variants which is in line with previous literature. AS may be seen as a precursor to the development of anxiety- and anxiety-related disorders, and a potential clinical marker for early diagnoses of anxiety disorders.