Genomic medicine: a new frontier of medicine in the twenty first century

Abstract

Although the concept of heredity has been in existence since ancient times, the science of genetics began to evolve only around 150 years ago. The Darwinian theory of evolution by natural selection made clear reference to hereditary factors that reflect at least some of the present-day concepts of the genetic basis of life. Mendel’s laws of inheritance, and successive discoveries in various aspects of genetics, laid the foundation for a number of disciplines covering different areas within the modern science of genetics. The emergence of human genetics was no exception. It has taken six decades since the recognition of DNA as the carrier of hereditary information to arrive at our present state in the science of genetics. The future now appears bright, opening up many new and challenging opportunities. During the last four decades, medical genetics has established itself covering clinical and laboratory diagnostic applications. The basis of medical genetics is grounded in a sound knowledge and understanding of principles governing ‘human genetics’. Clinical genetics is now a recognized medical specialty among several disciplines comprising the current spectrum of modern medicine. Fifty years after the discovery of the double-helical structure of the deoxyribonucleic acid [DNA] molecule (Watson and Crick 1953), the characterization of the virtually complete sequence and organization of the human genome was successfully accomplished (Lander et al. 2001; Venter et al. 2001). This major scientific achievement laid the foundation of ‘human genomics’; that section of the biological sciences which studies variations, mutations and functions of genes and controlling regions, and their implications for human variation, health and disease. This is strengthened by developments in the other areas of genomics relating to micro-organisms, animals and plants. The identification of all human genes and their regulatory regions provides the essential framework for understanding the molecular basis of disease. This advance has also provided a firm foundation for the future development of genomic technologies that can be applied to medical science. Rapid developments in global gene analysis, gene product analysis, medical bioinformatics, and targeted molecular genetic testing are destined to change the practice of medicine. However, many practicing clinicians perceive developments in genomics as primarily confined to the research arena with little clinical applicability. DNA/ RNA-based methods of disease susceptibility screening, molecular-based disease diagnosis and prognosis, and genomics-based therapeutic choices and prediction of treatment outcome are some of the key areas that are likely to influence the practice of modern clinical medicine. Undoubtedly, the science of genomics has tremendous potential for improving human health. The World Health Organization [WHO] has recently made several recommendations for the scope and application of genomics on global health (WHO 2002). It is acknowledged that the information generated by genomics will provide major benefits in the prevention, diagnosis and management of communicable and genetic diseases as well as other common medical diseases, including cardiovascular diseases, cancer, diabetes and mental illnesses (Cardon and Bell 2001). Together these constitute a major health burden, as reflected in chronic ill-health and mortality. In addition, a number of infectious diseases are associated with genomic mutations manifesting in the form of increased susceptibility, clinical severity, favorable and unfavorable response D. Kumar (&) Institute of Medical Genetics, University Hospital of Wales, Cardiff University, Heath Park, CF14 4XN Cardiff, UK e-mail: kumard1@cardiff.ac.uk