Psychiatric genetics in South Africa: cutting a rough diamond

Abstract

Psychiatric disorders place a considerable healthcare burden on South African society. Incorporating genetic technologies into future treatment plans offers a potential mechanism to reduce this burden. This review focuses on psychiatric genetic research that has been performed in South African populations with regards to obsessive-compulsive disorder, schizophrenia and bipolar disorder. Preliminary findings from these studies suggest that data obtained in developed countries cannot necessarily be extrapolated to South African population groups. Psychiatric genetic studies in South Africa seem to involve relatively low-cost methodologies and only a limited number of large national collaborative studies. Future research in South Africa should therefore aim to incorporate highthroughput technologies into large scale psychiatric studies through the development of collaborations. On a global level, the vast majority of psychiatric genetic studies have been performed in non-African populations. South Africa, as the leading contributor to scientific research in Africa, may provide a foundation for addressing this disparity and strengthening psychiatric genetic research on the continent. Although the elucidation of the genetic architecture of psychiatric disorders has proved challenging, examining the unique genetic profiles found in South African populations could provide valuable insight into the genetics of psychiatric disorders. 356 pharmacogenetic studies). The Afrikaners are an example of a homogenous population as they arose from a small founder population of 1000-2000 Dutch immigrants that arrived in South Africa in the 17th century. 6,7 The ancient southern African Khoisan population possesses the highest level of genetic diversity reported to date, while the Mixed Ancestry population shows the greatest global admixture of any of the world's populations analysed thus far. 8 Additionally, the Nguni-speaking Xhosa population shows a significant genetic contribution from the Khoisan in their genomes, reflecting admixture between these ancient individuals and ancestral Bantu populations; artefacts of this exchange are also linguistically evident through the click consonants present in the isiXhosa language. 8,9 The prevalence of psychiatric disorders in the different ethnic groups of South Africa is not known, although evidence from the South African Stress and Health Study 10 suggests very little difference from non-African populations. However, alarmingly, it appears that the majority of individuals suffering from psychiatric disorders in South Africa do not receive treatment. 11 Revised burden of disease estimates place neuropsychiatric disorders as the third highest cause of disability-adjusted life years in the country, mainly due to the extended morbidity of such conditions. 12 Unipolar depression, alcohol use, bipolar affective disorder, schizophrenia, drug use, obsessive-compulsive disorder (OCD) and panic disorder are neuropsychiatric disorders that fall into the top 20 causes of years lived with ...

No gene-by-environment interaction of BDNF Val66Met polymorphism and childhood maltreatment on anxiety sensitivity in a mixed race adolescent sample

“…The South African mixed race population is characterized by high levels of admixture (Tishkoff et al, 2009) and ancestral diversity (i.e. Khoesan, European and Asian ethnicity) (Hemmings et al, 2016; Wright, Niehaus, Koen, Drögemöller, & Warnich, 2011), suggestive of genetic heterogeneity, which may have influenced our results. Findings of this exploratory study are therefore preliminary.…”