Posts Tagged ‘ Genetic Engineering ’

Childhood Psychiatric Disorders: Will Genetic Engineering Ever Be A Solution?

Wednesday, February 27th, 2013

Following a stimulating Intelligence Squared debate, we’ve been discussing genetic engineering (think of it as directly changing DNA) here at Parents.com – both in terms of using it to create a “Super Baby” and to prevent disease. As a follow-up, let’s consider the likelihood of genetic engineering being a factor in the future for a number of childhood psychiatric disorders – or more to the point, the challenges that lay ahead. 

Autism Spectrum Disorder (ASD)

There would be hope that genetic engineering would be feasible in the future, as ASD is believed to be highly genetic in origin. However, the genetic basis for ASD is not clear. In fact, there may be a range of genetic etiologies. For example, some cases may be due to a rare genetic mutation – but there could be a number of mutations that can lead to ASD (not just one identified disease gene) making the idea of genetic engineering more challenging. The majority of ASD cases may reflect a complex mix of genetic and environmental influences – and the latest statistical modeling suggests that the genetic contribution to ASD may not be as strong as previously thought (and that the role of the environment may be more pronounced). For those situations, the idea of using genetic engineering is even more murky, because there may be many genes involved and they probably interact with a variety of environmental factors. All of this is not to say that genetics won’t lead to possible biological therapeutics – rather it’s to point out that the lure of genetic engineering as a solution may not be the avenue that will be pursued.

ADHD

The best evidence to date suggests that ADHD is due to a mix of genetic factors along with the influence of a number of environmental factors. As discussed above, this makes the pure application of genetic engineering difficult to imagine. There may a large number of genes involved, each of which may only have a small effect on the likelihood of developing ADHD – which, simply put, would make it very difficult to know what genes to target. Again, it’s tough to predict where genetic research will go, but while it may certainly lead to improved treatments over time for ADHD, it’s tough to see the role of genetic engineering.

Depression

You’re starting to see a pattern here. Like ADHD, depression is also thought to be influenced by many genes as well as the environment. As discussed above, this constellation of risk factors does not suggest that genetic engineering will be a factor any time soon.

Conduct Disorder (CD)

This is the same deal as the case for ADHD and depression – and it may be that the environment plays an even stronger role in the etiology of CD.

Conclusion

The idea of genetic engineering is provocative. But the reality may be far in the future for most childhood psychiatric disorders – and in many cases it may not be the way in which genetic research gets translated into prevention and intervention.

Molecular Biology Test via Shutterstock.com

 

 

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Genetically Engineered Babies: Good Or Bad Idea?

Wednesday, February 20th, 2013

Would you want the option of harnessing the power of genetics to alter the DNA of your unborn child? Would you want this to prevent disease? Select physical characteristics? Or “design” your baby by changing the genetic code? 

Such was the topic of an Intelligence Squared debate held in New York City on February 13. Two experts argued that genetic engineering should be banned; two experts argued that it should be supported. The audience – of which I was a part – had a chance to vote both before, and after, the arguments were made. Prior to the debate, I was in favor of supporting genetic engineering – with many caveats. After listening to both sides present their point of view, I pondered three points to help me come to a final decision:

Is genetic engineering feasible?

The science of genetics is fast paced. Although we don’t have much in the way of actual examples, it is worth assuming that it would be feasible at some point in the future. That said, my position is that it will only be worth considering for diseases or traits that are shaped by a single gene. There are certainly many diseases for which this is the case, such as cystic fibrosis and Huntington Disease. I certainly think there may come a time when it would be possible to try to intervene biologically to correct the mutations that underlie these conditions. However, bear in mind that most diseases and traits are believed to be due to the effects of many genes (polygenic) as well as environmental influences (multifactorial). Even height, which we think of as being “genetic”, is due to the combined effects of many genes as well as environment, and hence is multifactorial. Eye color is not as straightforward in terms of genetics as you might think. So … I think we can have the conversation about those more rare diseases and traits that are due to the “necessary and sufficient” effects of a single gene which can be identified along with the gene product. Having the debate about polygenic and multifactorial traits (more on this below) seems to be morphing into science fiction rather than science (unless science proves that wrong).

Why should we pursue it?

The primary reason would be to eradicate disease, especially disorders that are known to cause premature death. Certainly think about the life of a kid with cystic fibrosis – who wouldn’t want to spare a child that? Huntington Disease is an interesting example because it reveals that genes don’t just express themselves at birth – they can have a deleterious effect in adulthood. If we could alter that gene and prevent Huntington Disease, shouldn’t we do that? Some cases of breast cancer involve the primary (though not fully deterministic) effects of a single gene – again, if we could alter that mutation, wouldn’t we do that?

Why shouldn’t we pursue it?

Many feel that there are ethical considerations. For example, some do not like the idea of changing DNA – in essence, the thought is that it should be left alone. However, in terms of disease treatment, it’s worth noting that we do have examples of changing what a mutation does, and in the process keeping people healthy. A great example is a type of lymphoma caused by the “Philadelphia Chromosome” (so named because the mutation was discovered by scientists at the University of Pennsylvania). While the discovery was made in 1960, it took about 40 years to discover a genetically tailored drug that keeps the disease in check and allows people with this mutation to lead healthy lives. Although this isn’t genetic engineering in the strict sense, the principle is the same – alter the effects of DNA to change the likelihood of disease.

Less clarity surrounds the use of  genetic engineering to try to give parents the opportunity to control a variety of traits in their child to be – their appearance, personality, intelligence. As discussed by Melanie Abrahams, the pregnancy editor at Parents.com, the issue is would you want to create a Super Baby if you were given the choice? Again, my two cents to throw into this part of the debate is that it’s hard for me to imagine genetic engineering for polygenic, multifactorial traits – which includes appearance, personality, and intelligence. But then again, we don’t really know, do we?

Where do I land on this issue?

Bottom line, I support the idea of genetic engineering for well-defined diseases that are known to cause suffering and death. I don’t see any difference between designing a drug that is tailored to counter the biological effects of a mutation, and in principle directly altering the mutation. I don’t like the idea of applying genetic engineering principles to anything other than disease. Even “black or white” questions have their gray area.

DNA Structure via Shutterstock.com

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