Genetic Testing

In the case of genetic disease, options often exist for presymptomatic diagnosis—that is, diagnosis of individuals at risk for developing a given disorder, even though at thetime of diagnosis they may be clinically  healthy. Options also may exist for carrier testing, studies that determine whether an individual is at increased risk of having a child with a given disorder, even though he or she personally may never display symptoms.  Accurate predictive information can enable early intervention, which often preventsthe clinical onset of symptoms and the irreversible damage that may have already occurred by waiting for symptoms and then responding to them. In the case of carrier testing, accurate information can enable prospective parents to make more-informed family- planning decisions. Unfortunately, there can also be negative aspects to early detection, including such issues as privacy, individual responses to potentially negative information, discrimination in the workplace, or discrimination in access to or cost of health or life insurance. While some governments have outlawed the use of presymptomatic genetic testing information by insurance companies and employers, others have embraced it as a way to bring spiraling health-care costs under control. Some communities have even considered instituting premarital carrier testing for common disorders in the populace. Genetic testing procedures can be divided into two different groups: (1) testing of individuals considered  atrisk  from phenotype or family history and (2) screening of entire populations, regardless of phenotype or personal family history, for evidence of genetic disorders commonin that population. Both forms are currently  pursued in many societies. Indeed, with the explosion of informationabout the human genome and the   increasing identification of potential “risk genes” for common disorders,such as cancer, heart disease, or diabetes, the role of predictive genetic screening in general medical practice is increasing.