Science & Technology, UK (Commonwealth Union) – Gene testing, is a medical test that examines a person’s DNA to identify any changes or mutations in their genes. Gene testing can help identify the risk of developing certain genetic disorders, inherited diseases, or predispositions to certain conditions.
Professor Aroon Hingorani of the University College London (UCL), has indicated that conducting a test on a population for multiple genes is restricted to its capability to forecast disease risk.
DNA sequence generally varies between individuals at a variety of points throughout the genome. Certain genetic variants impact individual risk of common diseases like dementia, cancer, diabetes, and cardiovascular disease, via effects for expression or function of the encoded proteins. Factors playing a role on these variants on disease risk in any person can be summarized by producing a polygenic risk score according to researchers.
Strong claims in regards to the transformative possibilities of polygenic risk scores in forecasting, prevention, and early detection of disease and such testing have gained attention from policy makers and the commercial establishments. But evaluations made in an article appearing in the British Medical Journal, had clinical scientists from UCL, The Institute of Cancer Research, London, together with the University of Oxford point out that the forecasting ability of these had restrictions.
Co-author Professor Hingorani of the UCL Institute of Cardiovascular Science, and the Cardiovascular Theme Lead for the UCLH NIHR Biomedical Research Centre as well as a Consultant in Internal Medicine at UCLH, says “Population-wide ‘polygenic scoring’ is inherently limited because many cases of disease occur among people who do not have high polygenic scores and many of those with high polygenic scores do not develop disease.”
NHS genetic testing has presently drawn its attention towards a small number of well-known disease mutations which strongly increase the risk of disease, like BRCA1 and BRCA2 in breast and ovarian cancer.
Polygenic scoring provides a unique kind of genetic testing which instead has explorations across 1000s of common variants in an individual’s DNA, where each can individually have only a minor effect on risk, to obtain a collective evaluation of the genetic risk of disease.
The 2 recent Government reports demonstrated a marked interest for polygenic scores in health care and assert that they provide a ‘step change’ for the screening of disease.
The National Health Service is presently joining hands with the UK’s most extensive research programme, Our Future Health, in providing risk information based on polygenic scores to 5 million individuals within the population of the UK. This information is expected to notify clinical decision-making together with access to screening as indicated by researchers.
Researchers pointed out that since polygenic risk scores only show a minor proportion of overall disease risk, that they must show the full context, with the normal background disease risk given for contrasting for patients and clinicians.
They provided an example, where women in the top 5% of polygenic scores for breast cancer have a 19% lifetime risk of getting the disease, when contrasted with a population risk of 11.8%.
Lead author Dr Amit Sud, Academic Clinical Lecturer in Genetics and Epidemiology from The Institute of Cancer Research, London, says “There is a huge amount of enthusiasm about polygenic scores, and they do have the potential to improve our ability to predict who will or will not develop a disease, albeit rather modestly.
“But we argue that the benefits and harms surrounding the use of polygenic scores are carefully evaluated before they are widely implemented. Given most of the disease in a population occurs in people who are not at high polygenic risk, these scores should not detract from effective population-wide screening and interventions to address modifiable and impactful risk factors like smoking and socioeconomic deprivation.”
