Gene Therapy, Genetic Testing, and Uses of Genetic Information - Case J2
Helen Freitag is a physician and geneticist who has conducted
groundbreaking research on the genetic basis for Huntington's
disease, a debilitating, incurable disease that slowly robs its
victims of mental and physical functioning and is ultimately fatal.
Onset typically occurs in the late 40's to early 50's and the disease
may progress in excruciating fashion for up to 15 years. The ultimate
goal of Dr. Freitag's research is to find the sequence defect that
causes the disease so that some mechanism of repairing the defect can
be developed and implemented through gene therapy. In the meantime,
Dr. Freitag's task is to locate the gene, which is done by
identifying a genetic marker -- a sequence of genes that are not
responsible for the disease itself, but that are detectable and
inherited in very close correlation with the defective genes.
Dr. Freitag believes she has uncovered a highly predictive marker
and wishes to conduct a special project in which she would
characterize the inheritance of the marker in families with a history
of Huntington's disease. This project will confirm the predictive
value of the marker.
- Given the moderate uncertainty with regard to the predictive
value of the marker, what should Dr. Freitag tell her research
subjects when she finds that they have the genetic marker? What if
the marker were predictive in every case? How might she involve
patients in this decision and what issues might they consider?
- Assume this is not a project of research, but a diagnostic
procedure in which the predictive value of the marker were certain.
If you knew you had a 50% probability of inheriting the defective
gene, would you choose to take this test? Why or why not?