Browsing by Author "Womersley, Jacqueline"

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    Examining the influence of childhood trauma and epigenetic variation in brain-derived neurotrophic factor on anxiety sensitivity
    (Stellenbosch : Stellenbosch University, 2022-02) Chifamba, Leah; Martin, Lindi; Seedat, Soraya; Hemmings, Sian; Womersley, Jacqueline; Womersley, Jacqueline; Hemmings, Sian; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Biomedical Sciences. Molecular Biology and Human Genetics.
    ENGLISH ABSTRACT: Anxiety sensitivity (AS) is defined as the likelihood of interpreting anxiety-related bodily sensations as having potentially harmful effects on psychological and physical wellbeing. Anxiety sensitivity is a risk factor for the development of anxiety disorders. The aetiology of AS is linked to genetic and environmental interactions. One environmental factor that has been linked to AS is childhood trauma (CT). The gene encoding the brain-derived neurotrophic factor (BDNF) has been implicated in psychiatric disorders, as well as neuroplastic changes that can occur after CT exposure. These changes can occur via epigenetic mechanisms, chemical modifications of DNA that alter expression without altering DNA sequence. DNA methylation is one epigenetic mechanism. The aim was to determine the associative and interactive effects of CT and epigenetic variation in BDNF on AS in adolescents from South Africa. This study investigated BDNF single nucleotide polymorphisms (SNPs), and DNA methylation associated with AS and CT effects in 951 participants who self-identified as being Xhosa or South African Coloured (SAC). Six BDNF SNPs, rs11030099, rs6265, rs11030101, rs2049046, rs908867 and rs1491850 were genotyped in 951 participants. Methylation of BDNF promoter I CpG sites was assessed in a subset of participants (n = 90). Statistical analysis was performed using R programming. In Xhosa females, the rs11030101 TT genotype was associated with decreased AS (p = 0.032). Furthermore, rs2049046 AT genotype was associated with decreased AS (p = 0.009) in SAC females. The interaction of CT with the BDNF rs2049046 AA genotype was associated with lower AS (p = 0.029) in Xhosa females. No significant association was found between CT, AS and methylation, also no significant genetype interaction with CT on methylation was identified. Our results provide insight into the role of genetic variation in BDNF on AS in adolescents and emphasises the importance of examining the influence of gene x environment interactions on AS in differentiated ethnic and sex groups.