human genome project, The

Health Progress, Mar/Apr 2001 by Reilly, Philip R

In June 2000, scientists gathered in Washington to announce they had completed the first survey of the entire human genome and had roughly established the sequence of approximately three billion genetic letters that make up the code of our genes. This achievement has profound implications that will take us a long time to understand. This discovery, at least for me, is deepening the mystery of what it means to be human, not simplifying it.

But what is the nature of this Human Genome Project milestone? What are the near-term, mid-- term, and long-term implications? Most importantly, how will Catholic health care address these potential ethical dilemmas?

NEAR-TERM IMPLICATIONS

Cancer Treatment In the next five years, we will see major advances in identifying persons at risk for certain cancers. These advances have already begun with both breast and colon cancer. Cancer, in many respects, is a genetic disease. Cancer is created by a series of genetic errors in the somatic cells of our body. Researchers at Johns Hopkins have shown that colon cancer is the result of five to seven different genetic errors that shut down certain protective mechanisms; when they've all failed over 50 to 60 years as cells divide, the result can be a form of cancer. Cancer happens because of changes in the DNA molecule, although environmental agents cause many of those changes.

Heart Disease Even though the major risk factors for heart disease are high cholesterol, high blood pressure, a sedentary lifestyle, diabetes, and family history, half the people in the United States who die of heart disease this year will have normal cholesterol and normal blood pressure, exercise regularly, and not have diabetes. Obviously other things need to be learned about heart disease, and many of the risk factors will likely turn out to be genetic. One risk factor won't explain 10 percent or 20 percent of this risk-the answer will be several smaller risk factors. We will need very powerful tools, which are being developed, in the area of bioinformatics to crunch all these risk numbers and create a profile. Many problems will be associated with assessing those risks. In a way, the genetic physician of the near future will be somewhat like a meteorologist-right most of the time, but not completely certain about the risks and outcomes.

MID-TERM IMPLICATIONS

DNA-ased Newborn Screening Virtually every child in the United States, by compulsory state law, is currently screened for a number of genetic disorders that can be treated by intervention, such as phenylketonuria and hypothyroidism. However, in the next 10 years, we are poised to greatly expand the number of screenable disorders, which raises fundamental questions. For example, what constitutes a disease? What should we be screening for? Why? What criteria do we need to know to treat the disease? How are we going to share the information?

Personalized Pharmaceuticals The pharmaceutical industry has made a multi-billion-dollar bet on an entirely new approach to drug development in which pharmaceuticals will be tailor-made to individual DNA differences. Not one drug for a single person-although that may be possible 100 years from now-but different drugs geared toward different groups of patients. For example, for a given disease, 10 percent of patients might react negatively to a drug that would help the other 90 percent. If we could isolate that 10 percent and not give them that drug, a drug that might have been kept off the market because of a bad risk profile would be an excellent treatment for the other 90 percent.

Expanded Premarital Screening Many genetic tests are offered to people before they marry, such as for sickle cell anemia among African-Americans, TaySachs disease among Ashkenazi Jews, and cystic fibrosis among people of northern European extraction- More of these tests lie in our future. This type of screening raises profound questions abut the role of science and medicine in human reproduction that must be confronted squarely-and soon.

Somatic Cell Gene Therapy Gene therapy, despite its current riskiness, is inevitable in the next 10 years. Hurdles will appear and mistakes will be made, but both will eventually be overcome.

Xenotransplantation Xenotransplantation refers to the genetic manipulation of animals, such as the pig, to develop organs that our bodies would recognize as human. Xenotransplantation has the potential to overcome the chronic lack of organ donors, such as for people with end-stage kidney disease. Xenotransplantation is likely to occur in the next 10 years and will be a two-edged sword.

LONG-TERM IMPLICATIONS

I hesitate to peer much more deeply into the future than 20 years, considering how far we've come in the last 20 years. In this time frame, I see a set of profoundly challenging ethical and social dilemmas.

Universal DNA Banking Universal DNA banking is a very realistic possibility for the next generation. This term refers to collecting DNA samples of every individual at birth, storing the data, analyzing the data, and using it to guide that person's health. Here, room for nefarious misuse exists: What kinds of controls do we need to move ahead in this arena in a reasonable way?