3. Electronic Theses and Dissertations (ETDs) - All submissions
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Item Duchenne and Becker muscular dystrophy: implications for at-risk individuals(2010-04-16T09:22:31Z) Erasmus, SurethaDuchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) are severe X-linked recessive, degenerative neuromuscular diseases. DMD/BMD are caused by deletions, duplications and point mutations in the DMD gene situated on the X-chromosome. Studies have shown that the risk of being a carrier for DMD/BMD has a psychosocial impact on individuals and affects their requests for DNA testing and their choices regarding reproduction. Very few articles have been published to date and this study is the first South African study to investigate the behaviours of individuals in DMD/BMD families. The study aimed to investigate why individuals attended genetic counselling and who referred them. It also aimed to identify factors that influence at-risk individuals‟ decisions regarding genetic counselling, carrier testing and reproduction. The study was retrospective and data were obtained by reviewing genetic counselling files at the Division of Human Genetics, National Health Laboratory Service and the University of the Witwatersrand. The sample consisted of 79 files of families seen for genetic counselling regarding DMD/BMD from 1995 to 2008. Subjects included the maternal female relatives of affected individuals, who were all of reproductive age (15-49 years); the total number of at-risk individuals identified was 237. Subjects were divided into three groups according to their assigned reproductive risks: low (0-9%), intermediate (10-24%) and high (>25%). The influence of reproductive risk and other identified variables on decisions to attend genetic counselling, have carrier testing and having children were analysed using chi-squared and logistic regression analysis. iii Reproductive risk and relationship to the affected individuals were shown to be significant predictors of individuals‟ decisions. Other factors that contributed significantly to the behaviour of at-risk individuals were ethnicity, age, whether a mutation was de novo and whether an individual had affected children.Item The use of genetic tests by the individual life insurance industry in South Africa(2010-02-24T07:09:43Z) Kinsley, NoeleneThe life insurance industry’s ability to access genetic test results has raised public concern regarding loss of privacy and discrimination. The insurer requires access to genetic test results to reduce the impact of individuals changing their insurance purchasing behaviour based on a predictive genetic test result, of which the insurer is unaware (anti-selection). In South Africa, industry guidelines have been established to reduce the risk of genetic discrimination whilst enabling insurance companies’ access to this information for appropriate assessment of insurance risk. This study was the first to investigate the use of genetic tests by the life insurance industry of South Africa and their compliance with the guidelines, in order to identify behaviour that could result in genetic discrimination or unexpected risk exposure for the insurer. A structured interview process was conducted with 13 companies (8 insurance companies and 5 reinsurance companies), representing the individual life insurance industry. The interview guide was structured in a manner to gain insight into the companies’ approach to using genetic information, including genetic test results, in defining the policy terms of an individual’s life insurance contract. This study found that the companies’ responses to genetic information, particularly genetic test results, were demonstrated to be aligned with the regulatory guidelines. Irregularities in their processes were noted and these could lead to discrimination or increased risk exposure for the insurance company. These resulted from inconsistencies noted in the companies’ understanding of the genetic disease mechanisms of a medical condition, which is used to interpret the genetic information to assign risk. In conclusion, this study identified the need for a consistent approach to the interpretation of genetic information which would reduce the risk of genetic discrimination. This may be established through the support of specialist genetic services.Item The practices, knowledge, and attitudes about common hereditary cancers: survey of general practitioners in Johannesburg(2009-02-26T09:23:14Z) Van Wyk, ChantelABSTRACT INTRODUCTION: Cancer is one of the most common diseases in the developed world and both genetic and environmental factors play a role in the development of cancer. About 5-10% of all cancers are due to predisposing genes. Some of the more common inherited cancer syndromes are hereditary breast and ovarian cancer (HBOC) and two colorectal cancer syndromes, familial adenomatous polyposis (FAP) and hereditary nonpolyposis colorectal cancer (HNPCC). Recognition of cancer susceptibility can allow “at risk” individuals and families to participate in cancer risk assessment, genetic testing, and various cancer prevention strategies. As the public is becoming more aware of inherited cancers, it is expected that there will be an increasing demand for genetic services and testing. For this reason more GP involvement is required to assess patients and families at risk and refer them appropriately. Since the Clinical and Counselling Section, Division of Human Genetics, National Health Laboratory Service and University of the Witwatersrand, Johannesburg is establishing a cancer genetics service it woud be of great value to assess the GPs’ practice, knowledge and attitudes with regards to cancer genetics and this was therefore the aim of this study. METHODOLOGY: A quantitative, exploratory research design was chosen and GPs in the Johannesburg area were selected as subjects. After the completion of a pilot study a research package was mailed to 196 GPs. This package was sent out twice and both times the GPs were asked to respond within 3-4 weeks. The final sample consisted of 61 GPs and the data were analysed using descriptive statistics. RESULTS: Of the 61 participants more male GPs (42, 69%) than female GPs (19, 31%) responded and there were about an equal number of GPs practicing alone (29, 48) and in a multiple practice (32, 52%). Twenty two (33%) of the GPs had never had personal experience of cancer. Practices: The GPs made use of several cancer screening procedures but obtained limited information on cancer history from their patients particularly from second degree relatives and about age of onset. Very few subjects (15, 25%) reported that they assess patients’ risk for inherited cancer susceptibility and only 22 (36%) reported that they refer patients to other facilities for risk assessment and genetic testing. Knowledge: Only 32 (52%) of the GPs were aware of genetic testing facilities and 54 (86%) reported never having received advertising material to promote genetic testing for cancer susceptibility services. They also are not aware of genetic counselling facilities but do feel patients should have genetic counselling by a genetic counselor, clinical geneticist or oncologist before genetic testing. Even though genetic testing for inherited cancer susceptibility is only available at some academic institutions, mostly on a research basis, the GPs seem to be unaware of the availability of genetic testing in South Africa for colorectal cancer genes (8, 13% and 9, 15%) but 28 (46%) knew about breast cancer genes. They were not aware of the autosomal dominant inheritance of hereditary breast cancer and the percentage of individuals with breast cancer who carry the BRCA1/2 gene nor did they know the penetrance of HNPCC genes. Attitudes: The subjects’ attitudes to genetic testing for inherited cancer susceptibility were positive although they reported that they were unaware of several general factors regarding cancer genetic testing. The GPs had limited knowledge about inherited cancers and do not take an active part in cancer genetic management. However, 53 (87%) of the GPs reported interest in learning about these services and expected to play a role in cancer genetics in the future. CONCLUSION: The findings of this study suggest that there is a need to educate GPs about the basic cancer genetic concepts so that they can identify patients at risk for an inherited cancer syndrome. They need to be informed about the genetic tests currently available for the inherited cancer syndromes, and about genetic counselling and testing facilities.Item Molecular metaphors taking on lives of their own: An investigation of metaphor in the conceptualisation of genetics and immunology(2006-02-09) Brom, Lauren SylvanGenetics and immunology presently hold tremendous possibilities for changing the future through their biotechnological applications. To comprehend such complex subjects metaphor is generally employed. It is my contention that as these scientific concepts are repeatedly reinforced in both scientific and mass media representations, the metaphors suffuse our conceptual system to such an extent that they are no longer recognised as metaphors. Instead, they tend to be viewed as scientific ‘fact’. I have termed such pervasive metaphors, ‘concept metaphors’. I argue that the predominant concept metaphors regarding genetics and immunology are ‘information coding’ and ‘militarization’, respectively. Through this research, the origins of these concept metaphors as well as the extent to which they influence our current perceptions of life and health, become startlingly patent. I conclude by demonstrating how the utilisation of novel metaphors can significantly alter our conceptualisations and consequently, perceptions of these areas of molecular biology.