On BioScience and Life and Such

Archive for March, 2008|Monthly archive page

Add this to the “uses of DNA” collection

In Uncategorized on March 28, 2008 at 7:20 pm

This post follows previous posts 10 ways to use your DNA and 9 more ways to use DNA. The collection so far: 3 blog-items containing 21 uses.

20. Will coffee make you sick ? Consumer genetics will tell you if you are likely to brake down coffein slowly or rapidly (SNP CYP1A2*1F in the CYP1A2 gene). The health implications are clearly overrated, but perhaps you would still find it interesting to know just how much coffee you have to drink in order to read DNA blogs all night.

21. Quit smoking. Nicotest analyzes two genes Cyp2A6 og DRD2. The testresult will tell the company which of its quit smoking products to sell you. However, if you look really hard you will find (faq, How does it work, section 4 second line and down), that the actual link to genetics is quite weak.

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Should public health care pay for IVF-treatment ?

In Uncategorized on March 18, 2008 at 9:34 am

Some developed countries with public health care will offer in-vitro fertilization (IVF) to aid couples with their reproductive problems. Having trouble conceiving is thus regarded as a medical problem and treatment although expensive, is paid for through public health services. Now, nature news reports on a drive to extend such IVF-treatment to developing countries as well.

Why ?

Because:

“The inability to have children can create enormous problems, particularly for the woman,”

…………problems like……………….

“She might be disinherited, ostracized, accused of witchcraft, abused by local healers, separated from her spouse or abandoned to a second-class life in a polygamous marriage.”

I know perfectly well that I myself, am fortunate to have my own children. I thus, may not be able to understand the suffering that infertility can lead to (especially in the developing world).

Nevertheless, trying to be objective on this issue, isn’t it obvious that this is a misuse of health resources ?

In the developed world I find it immoral to spend public resources and money, on IVF. Adoption can help children who would otherwise suffer and in my mind, should be the alternative for infertile couples. Of course one cannot and should not, stop people if they would like to pay for assisted reproduction themselves. But, treating infertility is not a public responsibility.

In the developing world where resources are scarce, I find it even more immoral. The problem for infertile women in these countries is so clearly, a social problem, not a medical one. Put the money towards making them treat their women better, instead of giving credibility to prejudice and discrimination by treating this condition.

Also, in a world soon to be overpopulated, isn’t this just another step towards doom ?

9 more ways to use DNA

In Uncategorized on March 12, 2008 at 1:19 pm

In a follow-up to my previous post 10 ways to use your DNA, here are 9 more uses:

11. Artwork. DNA Art Forms, dna11 and DNA-Artistry all isolate your DNA from a swab-sample and subsequently chop it up to create a pattern that is unique to you (similar to the old way of determining human identity). The product is a piece of art to put on your wall. You can see examples here and here.

12. Testing for predisposition to psychiatric disorders. Three companies offer this service, NeuroMark, Psynomics and SureGene. These tests should however, under no circumstance be confused with proper diagnostic tests, as stressed in this article.

13. Genetically customized flowers. Blue roses to replace the now outdated red ones.

14. Test your athletic abilities. Although most of us are probably painfully aware of our limitations already.

15. Glow in the dark goldfish.

16. Genetally optimized SPA-treatment. This however, looks like they have just renamed a nutrigenetics test. Note that nutrigenetic testing has been heavily criticised by authorities.

17. Surname testing which is basically a tool for genealogists.

18. Another such tool is Common birthplace testing.

19. And finally we have the appalling misuse of DNA offered here. This service has rightfully been deemed nonsens….

More uses to follow in what seems to develop into a collection of DNA-use posts.

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Proving the usefulness of pharmacogenetics

In Pharmacogenetics on March 7, 2008 at 10:37 am

Pharmacogenetics is the analysis of genetic markers that informs you of how efficiently you metabolize a given drug. Three genes are commonly analyzed: Cyp2C9, Cyp2C19 and Cyp2D6. These genes are important for the metabolism of drugs used for treating psychiatric disorders ranging from mild depression to severe psychosis. Of course, there are other things that influence how you respond to a drug, like compliance, diet and smoking, but the genetic differences have profound stand-alone effects. For a patient experiencing adverse events or no response at all when taking his medicine, pharmacogenetics can be a tremendous help in choosing more fitting medications (other brands or another (sub)class of drugs). Pharmacogenetics is thus, a vital part of personalized medicine.

There are a couple of arguments against pharmacogenetics analysis we in the diagnostic lab often meet:

1: It’s too expensive

2: The frequency of mutant alleles in the normal population does not differ from that in a given patient population. Thus, physicians seems to be unable to pick the right patients, and pharmacogenetics ends up as an inefficient (as well as over hyped and expensive) general screening method.

The first objection is easy to respond to: A patient that has to try many different drugs to achieve the desired effect without adverse reactions, costs much more than this once in a life-time test allowing a targeted approach straight towards the medication most likely to be suitable.

The second objection can be countered by saying that the overall frequency in a population is irrelevant to the patient, as finding his individual response to the drug is what matters. This argument however is just an argument favoring screening in any given field of medicine. One can still argue that the overall cost-effectiveness is insufficient. Thus, it seems that one either has to prove that physicians are able to pick the right patients (resulting in targeted diagnostics rather than general screening), or prove that general screening with pharmacogenetics is cost-effective.

Now, it seems that doctors using our lab are able to pick the right patients. This is based on results from a small study we have performed (more details below). The argument saying pharmacogenetics is just expensive general screening, thus, falls.

The study of whether general screening is also justified, we need to leave to others, but indications are that doctors are rapidly learning how to use pharmacogenetics.

Consequently, pharmacogenetics seems to be justified in terms of cost-effectiveness and it is undoubtedly in the best interest of the patient.

Our small study (595 patients) can be summarized like this:

Allele Our frequency (%) Frequency (%) in a normalpopulation with similar ethnicity
2C9*2 11,5 10
2C9*3 6,9 7,4
2C19*2 16,7 9,1
2D6*3 1,3 1,1
2D6*4 20,0 15,6
2D6*6 1,0 1,2
2D6 gene duplication 2,1 2,2
2D6 gene deletion 3,4 2,4

The frequency in all but three (2C9*3, 2D6*6 and 2D6 duplication which had similar frequencies), were higher in our selected population than the normal population. Consequently, it seems that physicians are able to pick the right patients. There seems to be no general screening of patients receiving psychoactive drugs, among physicians using our service.