One of the biggest hurdles for a plaintiff to overcome in toxic tort cases is establishing that exposure to a toxin resulted in his or her injury. Generally, causation is determined through a battle of expert witnesses, each contending that a toxin can or cannot cause the injury at issue. With advances in gene sequencing and identification, some plaintiffs have begun to use their genetic information in order to show that they were exposed to certain toxins and that such exposure was "more likely than not" the cause of his or her illness.
Biomarkers are measurable indicators of molecular changes in blood or tissue that can indicate an abnormal condition or disease. In relation to toxic tort cases, two of the most important biomarkers are those which show chromosomal rearrangements or specific gene mutations. These gene expression biomarkers can not only show that a person was exposed to a certain toxin, in some instances, it can also quantify the amount of exposure. Accordingly, a plaintiff who claims to have been injured by exposure to toxins could provide genetic information to establish both exposure and causation.
However, genetic testing, biomarkers, and gene expressions are not only tools to be used by plaintiffs. Defendants can use genetic information in order to determine whether a plaintiff was predisposed to developing the alleged illness, showing alternative causation. Additionally, a gene expression that is inconsistent with exposure to the toxin at issue, or alternatively, a lack of any gene expression at all, can firmly establish that a defendant was not responsible for the development of a plaintiff's illness. In this vein, a defendant can rely less on statistical rules of thumb and have a "battle of the experts" to explain how their toxin could not result in plaintiff's injury. Rather, with plaintiff's genetic data in hand, defendants can now provide objective information regarding plaintiff's individual molecular changes to definitively show a jury that their product did not cause a plaintiff's alleged injury.
With the benefits that genetic information can provide both plaintiffs and defendants in toxic tort litigation, it is surprising that genetic data has not played a more significant role in such cases. This may be explained, in part, by the historically high expense and time consuming nature associated with genetic testing. However, with advances in modern technology and medicine, results for certain genetic information, such as biomarkers, can be provided within a day or two at a cost of a few hundred dollars. As research continues to identify different gene expressions and the cause of said expressions, coupled with increased accessibility to testing, it is safe to assume that genetic information will play a dominant role in toxic tort litigation in the years to come.