Study Says DNA’s Power to Predict Illness Is Limited

NY Times ^ | April 2, 2012 | GINA KOLATA

[neverdem]

If every aspect of a person’s DNA is known, would it be possible to predict the diseases in that person’s future? And could that knowledge be used to forestall the otherwise inevitable?

The answer, according to a new study of twins, is, for the most part, “no.”

While sequencing the entire DNA of individuals is proving fantastically useful in understanding diseases and finding new treatments, it is not a method that will, for the most part, predict a person’s medical future.

So, the new study concludes, it is not going to be possible to say that, for example, Type 2 diabetes will occur with absolute certainty unless a person keeps a normal weight, or that colon cancer is a foregone conclusion without frequent screening and removal of polyps. Conversely, it will not be possible to tell some people that they can ignore all the advice about, for example, preventing a heart attack because they will never get one.

“The punch line is that this sort of personalized medicine will not in any way be the most important determinant of patient care,” said Dr. Bert Vogelstein of Johns Hopkins, who, with his colleagues and his son Joshua, analyzed the power of sequencing all of a person’s DNA to determine an individual’s risk of disease. The study, published online Monday in the journal Science Translational Medicine, involved data from 53,666 identical twins in registries from the United States, Sweden, Finland, Denmark and Norway. The registries included data on 24 diseases, telling how often one twin, both or neither got a disease.

Since identical twins share all of their genes, the investigators could ask to what extent genes predict an increased chance of getting a disease. Using a mathematical model, they reached an answer: not much. Most people will be at average risk...

[neverdem]

The Predictive Capacity of Personal Genome Sequencing

[JohnBovenmyer]

Before we can make good predictions we’ll need to know more than the DNA. We’ll need to know, and understand, their epigenetics, which is just now beginning to be studied and remains poorly understood, and quite possibly additional layers of complexity we haven’t even imagined yet. Life is incredibly complex and not easily simplified. Still, I expect we’ll find knowing just the DNA will be useful for a fair amount of things, just not as many as had been hoped.

[Theoria]

Obviously ‘nurture’ plays a important role. The fact that identical twins can differ in height, weight and illnesses, even though they share the same DNA. The list can go on and on.

[SunkenCiv]

GGG managers are SunkenCiv, StayAt HomeMother & Ernest_at_the_Beach	join list or digest view topics view or post blog bookmark post a topic subscribe
Thanks neverdem. Scientist Reveals Genome Secret: It's Him Scientist Reveals Genome Secret: It's Him by Nicholas Wade April 27, 2002 When scientists at Celera Genomics announced two years ago that they had decoded the human genome, they said the genetic data came from anonymous donors and presented it as a universal human map. But the scientist who led the effort, Dr. J. Craig Venter, now says that the genome decoded was largely his own. Dr. Venter also says that he started taking fat-lowering drugs after analyzing his genes... [M]embers of Celera's scientific advisory board expressed disappointment that Dr. Venter subverted the anonymous selection process that they had approved... Though the five individuals who contributed to Celera's genome are marked by separate codes, Dr. Venter's is recognizable as the largest contribution. He said he had inherited from one parent the variant gene known as apoE4, which is associated with abnormal fat metabolism and the risk of Alzheimer's, and that he was taking fat-lowering drugs to counteract its effects... Dr. Arthur Caplan, a biomedical ethicist at the University of Pennsylvania, said, "Any genome intended to be a landmark should be kept anonymous. It should be a map of all us, not of one, and I am disappointed if it is linked to a person." Venter spent millions or billions of other people's money so he would know to take fat fighting meds. Other folks get fired for surfin' the web at work. To all -- please ping me to other topics which are appropriate for the GGG list.

[neverdem]

So, the new study concludes, it is not going to be possible to say that, for example, Type 2 diabetes will occur with absolute certainty unless a person keeps a normal weight...

There's also LADA, latent autoimmune diabetes in adults, a type of Type 1 Diabetes, which the article says should, in theory at least, pick up as many as 75% of traditional Type 1 Diabetics.

FReepmail me if you want on or off the diabetes ping list.

[mamelukesabre]

obviously “nurture” doesn’t even explain it. Identical twins who grow up together often don’t look that much alike and have completely different health issues and personalities.

[Myrddin]

Falls in the same category as examining a Linux installation disk and trying ti divine if it eill be susceptible to a worm, trojan or virus infection.

[Myrddin]

Epigenetic changes during gestation cause phenotypic changes in the trajectory of development. Environmental toxins and variations in nutrients also change the way the initial software load of DNA plays out.

[mamelukesabre]

They gestate in the same womb at the same time in the same amniotic sac with the same placenta.

Try again.

[Gene Eric]

Good. Keep the curve balls coming, God.

No, you dumb mofus, I’m not anti-science.

[Myrddin]

Not always. I've read a bunch of twin studies. When the genetically identical twins have a blood supply that passes the "used" blood from one twin to the second one, the second one is born at a lower birth weight and usually with a measurably lower IQ. Fingerprints are different even with the same starting DNA. Read through the sections on epigenetics in
.

[trebb]

The Lefties are PO’d - if they can’t predict problems, they have one less basis to murder even more babies.

[bert]

The question in my mind is “who thought DNA revelation could be a universal predictor of future disease”

A few perhaps, but most , no

[bert]

Oh and for the record, is the slimes writer Gina the sister of Pina Kolota?

[exDemMom]

A few diseases are absolutely predicted by genetics, but in many cases, it is possible to find those defective genes without sequencing the entire genome. Huntington’s disease is one of those. But for most genetic diseases, we only know that a gene (or genes) are involved, but we still don’t know what triggers the disease.

Determining the role of environment vs. genetics will, no doubt, keep many researchers gainfully employed for decades to come.

[rod1]

Exactly!
The trajectories for most chronic diseases are established early in life and require misregulation of inflammation for disease onset. That makes it pretty clear where the big pay-off will be in terms of safety information, exposure avoidance, and meaningful prevention of chronic diseases. (Of course it is exactlty where we don’t look now in terms of safety testing of chemicals and drugs. This is despite the combined huge regulatory expense already required of companies and the pretense of regulatory agencies that we have chronic disease-relevant safety data to protect the health of kids).

[SuzyQue]

Really? I’ve never heard that. Every identical twin set I’ve ever know personally or read about, look pretty much identical, and have more similar physical experiences than do non-twins.