Through the many forms of genetic screening available today, doctors can find out whether a patient is susceptible to a certain disease, if an unborn child has a defect, or if a potential parent may pass on a genetic abnormality to their child. However, current methods cannot tell us about the patient’s current health or if an illness is developing. That may be all about to change with the advent of testing free-floating DNA.Discovered in 1948, these genetic fragments circulate in the bloodstream, and while it is still unknown how they survive outside of a cell, it has been found that some illnesses are correlated with increased levels of specific circulating DNA. If fully developed into a diagnostic tool, this could widen the options of doctors when deciding the next step for a patient.
For example, the current method for diagnosing genetic defects in an unborn child is amniocentesis, which requires drawing a small amount of amniotic fluid (and with it, cells from the child) from the amniotic sac surrounding the baby. This carries a small but very real risk of miscarriage. In the late 1990’s, researchers found small amounts of DNA from the baby circulated in the mother’s bloodstream: this DNA could be tested by drawing some of the mother’s blood, eliminating the risk that amniocentesis carries.
Genetic markers have also been found for retinal damage due to diabetes and even mad cow disease in cattle. Researchers are searching for genetic patterns for cancers that inform them of the location and state of the tumour to enhance treatment and hopefully increase survival rate. They also want to develop methods to test urine instead of blood for the circulating DNA, in order to run screening operations in areas where maintaining sterile conditions might be difficult, like in third-world situations.
In the future, genetic screening may become part of regular check-ups at our local GP, paving the way for very early diagnosis and more effective treatment.
By Student 42025302
Juncosa, B. (2009). DNA on the Loose: Next-Gen Blood Tests Tap Free-Floating Genetic Material. Retrieved March 25, 2009 from http://www.sciam.com/article.cfm?id=next-generation-blood-test
