Genetic Screening: Cure or Curse?

In the 2002 PBS documentary Cracking the Code of Life, which narrates the scientific effort to decode the human genome, one episode relates the story of the Lord family. Parents Tim and Allison Lord discovered that their son Hayden had Tay-Sachs disease when he began to miss developmental milestones when he was just a few months old. Tay-Sachs is a devastating genetic disorder in which the protein that breaks down gangliosides (a type of fat in the brain) is nonfunctional, resulting in a baby’s inability to break down this fat. The gangliosides accumulate in the nerve cells of the baby’s brain, noticeably impairing development by six months. As more and more gangliosides accumulate, nerve cells begin to die off, and the child’s development is not only halted, but reversed. Hayden Lord, a formerly happy, seemingly healthy baby lost the ability to smile, went blind, lost the ability to swallow, and had increasingly frequent seizures until he, like all babies with classical Tay-Sachs disease, died before reaching age 7. In the words of narrator Robert Krulwich, this heartbreaking disease is caused by only “one defective letter out of three billion,” meaning that a mutation in only one nucleotide in Hayden’s entire DNA sequence had caused his inability to break down gangliosides, and eventually, his death.

Krulwich went on to describe the Human Genome Project, which made a total sequence of human DNA from a small sample of healthy people available to the public, as “an early warning system for a whole host of diseases,” which could enable doctors to stop, treat, or “eventually” cure these diseases. Tim Lord expressed hope that the project would result in a test for a great number of genetic disease “so that parents could be informed of the dangers that faced them before they started to have children” and “not have the diseases affect a child.” But is this really what the Human Genome Project provides? And is this untempered, unwavering faith in the hopeful future of medical science beneficial for the regular, nonscientific community?

While the Human Genome Project has offered a means to begin to identify some genetic causes of disease, it is only a beginning. Many diseases don’t have as clear of a genetic cause as Tay-Sachs disease, and even if there were a single mutation as the cause of heart disease, and then another single mutation as the cause of lung disease, and so on, there is no guarantee that the ability to identify the genetic cause of disease will result in the ability to cure, or even in the ability to stop, the disease. Screening ability for genetic diseases has improved as a result of the Project, but this is not the cure-all that it might seem. Screening does not tell parents that they either will or will not have a healthy child; it may tell them that they have a 20% chance of having a baby with Downs Syndrome, or a 50% chance of having a baby with Tay-Sachs, or a 50% chance of having a baby with Cystic Fibrosis. For some diseases, the chances may be even less. How are potential parents supposed to deal with news like this? If they find a chance, even a small one, say 15%, that they will have a baby with a serious genetic disorder, they are then faced with two incredibly difficult alternatives–either take the risk to have children knowing that their children might face serious disability and even untimely death, or choose not to have children at all. What would you do?

-Mary Virginia Harper 

~ by mvharper on January 12, 2014.

3 Responses to “Genetic Screening: Cure or Curse?”

  1. That has definitely got to be an incredibly difficult decision – I can’t imagine having to make it as a parent. My hope though, is that this era of betting on statistics and dealing with uncertainty will only happen in the interim between identification and the finding of cures for these genetic diseases. Unfortunately, that era is probably going to be ours, and I’m certainly not looking forward to having to know and play those odds.

  2. I’m not sure what I’d do in this situation. Raising kids is all about having a plan and preparing for the future, and parents deserve to know these figures so they can plan their lives, so at very least I’m certain I would want to know the odds for my children. And while this situation might be an incredibly difficult one, I wonder if it might also lead to an increase in adoptions across the country.

  3. Your question regarding faith in this science as beneficial to the general public is intriguing. It seems to me that you’re right – it may not be helpful to people to be more dependent, because that’s the very thinking that might lead to a world like that of Gattaca. We may never be able to fully cure or prevent genetically influenced diseases, but reliance on it would lead straight to your later question about parental decisions. It would not be fair to anyone to force them to choose between having a child and putting that child in potential danger. It could be that we will be able to screen in this way, but reliance on these screenings would put many in an impossible position.

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