Markers for disease genes open new era in diagnostic screening

Nancy S. Wexler, PhD, is a clinical psychologist, a member of the department of neurology at Columbia University in New York City, president of the Hereditary Disease Foundation, and one of the principal investigators of the team that found the marker for Huntington's disease. Her curriculum vitae is impressive, but her future is uncertain. She stands a 50% chance of developing the disease she has studied.Like others at risk for Huntington's disease or adult polycystic kidney disease—another late-onset genetic disorder—she has been consigned to decades of uncertainty. There are no enzyme assays or easily identified chromosomal abnormalities that foretell these diseases. Those with a family history must go through their 20s, 30s, and possibly 40s looking for the symptoms of the disorder—and hoping that they won't find them.But this won't be the case much longer, if reports given at the 38th Annual Meeting of the American Society for