The human genome comprises some 20,000 genes, or 3 billion base pairs. Vari-ation in this genetic sequence is common and some of these variants affect gene function or the protein transcribed from it. Human characteristics are determined by the interaction of the genome with en-vironmental challenges, and differences between us thus result from variation in those challenges and in the genome itself. This is true of human susceptibility to dis-ease, and survival from it. Genetic varia-tion influences human behaviours which may predispose to health or disease; the risk of contracting an infectious disease, or of suffering diseases such as cancer or myocardial infarction; the development of complications; the response to any treat-ment administered; and thus the outcome of the disease state. Genetic studies can help shed light on the mechanisms which underpin disease processes, whilst perhaps suggesting ways in which treatment might be ‘personalised’, and novel therapeutic targets for drug development.
More sophisticated approaches to such en-deavours are required, given the failure to identify the bulk of gene variants of influ-ence using conventional strategies.