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I Had My DNA Picture Taken, With Varying Results

I Had My DNA Picture Taken, With Varying Results | Heart and Vascular Health | Scoop.it

A healthy 28-year-old with concerns about diseases in her family had three different companies check her genetic code. The discrepancies in their results were striking.

23andMe said the most elevated risks — about double the average for women of European ethnicity — were for psoriasis and rheumatoid arthritis, with lifetime odds of getting the diseases at 20.2% & 8.2%. But according to Genetic Testing Laboratories (GTL). The  lowest risks were for — you guessed it — psoriasis (2%) and rheumatoid arthritis (2.6%).

For coronary heart disease, 23andMe and GTL agreed that I had a close-to-average risk, at 26-29%, but Pathway listed odds as “above average.”

In the case of Type 2 diabetes, inconsistencies on a semantic level masked similarities in the numbers. GTL. said risk was “medium” at 10.3%, but 23andMe said risk was “decreased” at 15.7% . In fact, both companies calculated odds to be roughly three-quarters of the average, but they used slightly different averages — and very different words — to interpret the numbers. In isolation, the first would have left me worried; the second, relieved.

Medical ethicists worry about results like these: a lack of industry standards for weighing risk factors and defining terminology.

Scientists have identified about 10 million SNPs within our three billion nucleotides. But an entire genome sequencing — looking at all three billion nucleotides — would cost around $3,000; the tests I took examined fewer than a million SNPs.

“Imagine if you took a book and you only looked at the first letter of every other page,” said Dr. Robert Klitzman, a bioethicist and professor of clinical psychiatry at Columbia. “You’re missing 99.9% of the letters that make the genome. The information is going to be limited.”

Seth Bilazarian, MD's insight:

A life science executive told me recently how elated he was that he and his whole family had taken the"valuable"& progressive approach to have genetic testing.  Had he asked my opinion, I would have shared the experience outlined in this personal account, that my patients have had.
Genetic testing is not ready for prime time and is more likely to be misleading (predicting risk or providing reassurance) and imprecise.
Except for a few diseases like breast cancer genetic testing provides no medical decision making value.  A risk I am concerned about is the lifestyle modifications patient might fail to make because they are falsely reassured about modifiable risks like diabetes and coronary disease  

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DNA determinants of Blood Pressure Response to Antihypertensives

DNA determinants of Blood Pressure Response to Antihypertensives | Heart and Vascular Health | Scoop.it

My comment:  The personalized medicine revolution is still on the horizon. Being able to evaluate which drug would be best for a patient before trying multiple drugs would be desirable and of great benefit (less cost, less side effects) but insurance payers and guidelines have not yet caught up with this basic science.

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39 genetic association with hypertension (HTN) have been identified. This study looked at DNA characteristics (loci/SNPs) associated with HTN and blood pressure response to antihypertensive drugs (specifically the bgereically available atenolol or hydrochlorothiazide.  768 Caucasian hypertensive participants in the Pharmacogenomics Responses of Antihypertensive Responses (PEAR) study were evaluated.

Genotypes of 37 loci were obtained:  six reached nominal significance (p<0.05) and 3 were associated with atenolol BP response at p < 0.01.

The genetic score of the HCTZ BP lowering alleles was associated with response to HCTZ (p = 0.0006 for SBP; p = 0.0003 for DBP). Both risk score p values were < 0.01.

These findings suggest selected signals from hypertension GWAS may predict BP response to atenolol and HCTZ when assessed through risk scoring.

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Personalized Medicine Moves Closer

Personalized Medicine Moves Closer | Heart and Vascular Health | Scoop.it
In a major step toward personalized medicine, researchers reported they have sequenced the complete DNA material of more than 1,000 people from 14 population groups in Europe, Africa, East Asia and the Americas.

Generally, all humans share about 99% of the DNA code that shapes development, health, personality and other traits. But the common genetic variations that most people share account for only a fraction of the risk of inherited disease.

Genetic variation among people refers to the differences in the order of chemical units, known by the shorthand A, G, C, and T, which make up the three billion letters of DNA in the human genome. The differences can be as minute as a single character replaced by another, or can be sequences of characters that are out of order, missing, duplicated or inserted in the wrong place.

"The biggest question is trying to figure out how much of this variation is meaningful"

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