November 4, 1999
The Trouble with Testing
Genetic medicine presents Jews with powerful solutions, difficult questions
Not according to Dr. Jerome I. Rotter, co-director of the Medical Genetics-Birth Defects Center at Cedars-Sinai. "While the Jews are very special," he says, "when we talk about the distribution of disease, they're not all that special. Every population has a susceptibility to its own set of hereditary diseases." It's an important point to make, coming as it [did] at the conference "Genetic Medicine and the Jewish Population," was held at Cedars-Sinai Medical Center on Oct. 24.
While science has made enormous strides in creating tools to fight the genetic diseases that afflict many Jews, the impact of those tools have a profound and intimate effect on all of us, Jews and non-Jews alike. And as a result, our society is now confronted with some of the most complex and difficult questions we've ever had to face.
Our genes are the code that stores all the information needed to build a human being. Occasionally, through the process of evolution, a single gene can mutate, confusing that information and rendering an individual susceptible to disease. Sometimes an individual is just a carrier, meaning he will never develop symptoms of the disease, but might pass on that susceptibility on to his children. For recessive diseases, like Tay-Sachs or Gaucher disease, both parents must be carriers, and both must pass on an abnormal gene for a child to develop the disease.
Over the last half-century, scientists have developed methods to pinpoint specific mutations on individual genes, allowing them to test individuals for genetic diseases. And although most of us are aware of this work, few of us seem to understand its profound implications: In a very real way, science can now tell the future. Suddenly, we've entered a brave new world of medicine, and the benefits we already reap from this new paradigm are great.
This is uniquely apparent in breast and ovarian cancer, two of Ashkenazi women's most serious health concerns. While all women are susceptible to these diseases, Dr. Maren Scheuner, director of the GenRISK genetic testing and counseling program at Cedars-Sinai, says that when a family history of breast cancer is present, Jewish women are at a much greater risk than non-Jews of developing the disease.
While there are currently no easy cures, women who test positive for one of the genetic mutations that cause breast cancer can take steps to improve their chances of survival if the cancer does develop. "For high risk women, you'll just have a higher suspicion and start all the screening much earlier, usually around 25," says Scheuner. Now, most women begin screenings at age 40.
Genetic medicine's new tools mean that we can screen entire populations to find healthy carriers of a disease and prevent that disease from spreading, eliminating the need for any treatment at all.
Dr. Kaback is intimately familiar with this process, being one of its pioneers. He began the first screenings for Tay-Sachs in Baltimore in 1969, and in Southern California in 1971. Since then, his program has voluntarily tested more than 1.4 million adults, identifying and counseling almost 1,400 couples at risk for bearing children with the disease. "These families have had over 3,200 pregnancies, and of those, 620 were Tay-Sachs-identified," says Kaback. "With the exception of about 20 of them, the families elected to terminate the pregnancy." Certainly, abortion is an extremely difficult decision, but many parents found it a better alternative to watching their child develop this disease by six months of age, deteriorate into mental and physical paralysis, and finally die before age 5.
It's estimated that one in 25 Ashkenazi Jews is a Tay-Sachs carrier. Prior to genetic screening, the disease was so common among Jewish populations that hospitals across the country had special wards to care for these children. Today, only three to four Tay-Sachs babies are born in North America each year. Similar screening programs have been implemented to help prevent Gaucher disease, Canavan disease (a neurodegenerative disease) and cystic fibrosis, among other genetic diseases .
So genetic screening is wonderful, right? Not always. The process can quickly transform the most logical questions of science into sticky ethical dilemmas. Even such issues as a doctor's responsibility become obscured. "If I know that my patient carries a certain genetic trait, he may not be at risk for that problem, but his sister may be at risk," says Dr. Kaback. "Do I have an obligation to contact his sister? Suppose I don't contact her, and she has a child affected with that condition. Do I have any legal responsibility in that context?"
And the questions get even more existential. "If I'm tested for a genetic trait and have it," says Kaback. "Instantaneously the doctor who does that test knows that my brothers and sisters are at a 50 percent risk of having that same genetic trait. They know that my children have a 50 percent chance of having that trait. Who is the geneticist's patient? Is it the client sitting across the desk, or is it their extended family? Or is it the entire population group from which that individual is derived?"
The problem is that genetic screening can tell us the future, and knowing the future is always a double-edged sword. When you screen healthy individuals, you may find a gene for a disease that won't show up for years. "How does it affect the person's self-image," asks Dr. Kaback. "To know that they have a gene that's going to possibly cause them to have cancer or mental illness or some neurological problem or heart disease later in life? How does it affect their upbringing? How many Willie Mayses or Sandy Koufaxes might never have achieved excellence athletically, if someone knew they had a predisposition to some illness later in life when they were children?"
Dr. David L. Rimoin, director of Cedars-Sinai's Medical Genetics-Birth Defects Center, and one of the organizers of the conference would agree.
"The reality is that we can screen for every disease," he says. "And every one of us in the population, of any population, will be found to be carriers of several genetic diseases."
But Rimoin feels that this knowledge can do so much good, as it's done with Tay-Sachs, that it shouldn't be ignored. That's why he organized the conference, and why he is trying to start a Jewish genetics center at Cedars-Sinai.