Pro & Con: Should preimplantation genetic diagnosis be used to avoid inheritance of early Alzheimer's disease? (Opinion).

[YES] Testing for disorders with genetic predisposition has never been accepted as a prenatal diagnostic technique, even though there is technically no difference between its use in detecting early-onset or late-onset genetic predispositions and its use in detecting chromosomal and single-gene disorders with onset at birth or early childhood.

The difference is that if the fetus is found to be carrying the gene predisposing it to Alzheimer's disease or other early-onset or late-onset disorders, the couple has to make the extremely difficult decision of whether to terminate the pregnancy Such a decision could hardly be justified by genetic predisposition alone, since the clinical manifestations of the disease may be realized in the very distant future or not realized at all in some cases.

Alternatively, preimplantation genetic diagnosis (PGD) technology allows genetic testing of human eggs and embryos before pregnancy making it completely realistic to establish only potentially normal pregnancies without Alzheimer's disease or any other early-onset or late-onset disorder with a genetic predisposition. Therefore, prospective at-risk couples have the right to know about the availability of PGD technology so they can make the decision themselves about their reproductive options. My colleagues and I recently published an article on the first known PGD procedure for inherited early-onset Alzheimer's disease resulting in a clinical pregnancy and the birth of a child free from inherited predisposition to the disease (JAMA 287[8]:1018-21, 2002).

With no current prospect for the treatment of Alzheimer's disease, prevention of an inherited predisposition to Alzheimer's is the only option for couples at risk.

The extremely difficult life experience of families affected by inherited Alzheimer's disease or any other catastrophic early-onset or late-onset disorder--being unable to help their family members suffering from the disease and being afraid they will soon develop the disease themselves--makes them responsible for insuring that their children will not face the same difficulties.

Using PGD is better than having children without testing them, because children who aren't tested will have a 50% risk of getting Alzheimer's disease.

Dr. Anver Kuliev is director of ...