Is Genetic Analysis Beneficial?

One of the pressing questions in recent years is whether or not an individual's genes can predict their risk of developing diseases or illnesses later in life, such as cardiovascular disease, cancer, diabetes, or other varieties of common diseases that plague modern humans. When the human genome was finally decoded in 2003 the floodgates were literally thrown open as researchers began scrambling to find ways to use this new information about genes and their variations to determine whether or not various chronic diseases are tied to the genetic structure. The sheer number of companies which have opened in the wake of the genome project, offering genetic screenings and disease risk assessments is staggering, but at the end of the day one simple question remains: can an individual's chance of developing disease based upon their genetic makeup actually be predicted with any certainty?
According to a recent set of commentaries published in the New England Journal of Medicine, the answer is no. One of the authors of the commentary, David B. Goldstein of Duke University, suggests that, “with only a few exceptions, what the genomics companies are doing right now is recreational genomics. The information has little, or in many cases no, clinical relevance.”
Analysis of the genome on a global basis has shown some success, such as illuminating the differences between the genetic codes of healthy and unhealthy patients. Unfortunately, these differences—though measurable—do little to provide significant information as to actual risks or predictability of diseases. Researchers initially expected to find measurable genetic variations responsible for the different types of diseases, thus allowing predictions to be a simple matter, however, what they found instead was that the most common gene variants affect disease risk on a very marginal scale.
Goldstein suggests that the source of the difficulty can be found in the number of rare genetic variants, making screening far less helpful in predicting risk. For example, if only a small number of variables are involved in the process they could provide information on the biological nature of the disease's development, but the problem lies in the fact that complex diseases have exceedingly complex variations, which provides almost no direction to researchers. After more than 100 genome-wide studies conducted on thousands of patients throughout the world, virtually no evidence has been discovered which would provide any degree of certainty with respect to the prediction of disease in a given individual based simply upon his or her genetic makeup. As Goldstein says, “discovering rare variants… is beyond the grasp of the genome-wide association studies.”
While it is true that some diseases, such as sickle cell anemia and certain breast cancers can be caused by as few as one mutation on a single gene, the problem is that most diseases are far more complex and develop under a series of circumstances that require interaction between various genes and environmental factors. Thus, predictions regarding potential disease become virtually impossible due to the complexity of factors attributable to even a single mutation. Barring a revolutionary breakthrough, at this point in time, genetic screening for disease appears to be more relevant to the realms of science fiction than scientific research.