Just playing with Google this morning, I got the following statistics:

Direct to Consumer Medicine: 12,700,000 results
Direct to Consumer Genetics: 3,510,000 results
Pharmacogenomics (PGX): 1,450,000 results
Pharmacogenetics: 1,330,000 results
CYP2D6: 350,000 results

Of course, many of these results have nothing to do with the subject at hand, reflecting instead the way that Google searches by certain key words. Nevertheless, direct-to-consumer (DTC) genetic testing is hardly an obscure subject.

Recent newspaper articles in The New York Times and Boston Globe
have looked at direct to consumer genetic testing. Ryan Phelan, the CEO of DNA Direct (the business that sponsors this blog) is quoted in the Boston Globe article.

It’s important to recognize that “DTC genetic testing” covers an enormous spectrum. Much of this testing is ancestry testing, using mitochondrial or Y-chromosome DNA, or genomic screening to estimate the probability that an individual has descended from a particular set of geographic or ethnic ancestors. Other testing looks for genetic traits that are associated with disease risk or responses to medications (PGX). While there is some controversy about the significance or accuracy of some of these tests, all of them are based on serious science.

Unfortunately there is also some genetic testing that is simply bogus. This is testing that claims to use DNA analysis to specify, for example, dietary plans or skin care regimens. It’s unfortunate that this testing is conflated with the more serious analyses.

Please take a look at the articles cited above. You may need to register to view them on-line, but registration is free. I welcome your comments.

Technorati Tags: PGX, ancestry testing, direct to consumer

National Institutes of Health to Map Genomic Changes of Lung, Brain, and Ovarian Cancers The National Cancer Institute (NCI) and the National Human Genome Research Institute (NHGRI), both part of the National Institutes of Health (NIH), today announced the first three cancers that will be studied in the pilot phase of The Cancer Genome Atlas (TCGA) project. The cancers to be studied in the TCGA Pilot Project are lung, brain (glioblastoma), and ovarian. These cancers, which collectively account for more than 210,000 cancer cases each year in the United States, were selected because of the availability of biospecimen collections that met TCGA’s strict scientific, technical, and ethical requirements… The whole story is at The Cancer Genome Atlas site.

Technorati Tags: human genome, cancer genome atlas, lung cancer, ovarian cancer, brain cancer, glioblastoma

What follows is from the National Center for Biotechnology Information. I think it’s one of the best descriptions of a SNP. It’s important to remember that when considering SNPs in the context of pharmacogenetics, the actual SNP may not be the cause of a particular response (as, for example, the SNP associated with the ultrametabolizer form of cytochrome P450 (CYP2D6). Some SNPs probably are causes, while others are best considered markers.

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A Single Nucleotide Polymorphism, or SNP (pronounced “snip”), is a small genetic change, or variation, that can occur within a person’s DNA sequence. The genetic code is specified by the four nucleotide “letters” A (adenine), C (cytosine), T (thymine), and G (guanine). SNP variation occurs when a single nucleotide, such as an A, replaces one of the other three nucleotide letters—C, G, or T.

An example of a SNP is the alteration of the DNA segment AAGGTTA to ATGGTTA, where the second “A” in the first snippet is replaced with a “T”. On average, SNPs occur in the human population more than 1 percent of the time. Because only about 3 to 5 percent of a person’s DNA sequence codes for the production of proteins, most SNPs are found outside of “coding sequences”. SNPs found within a coding sequence are of particular interest to researchers because they are more likely to alter the biological function of a protein. Because of the recent advances in technology, coupled with the unique ability of these genetic variations to facilitate gene identification, there has been a recent flurry of SNP discovery and detection.

Technorati Tags: pharmacogenetics, DNA, SNP

If you’re actively engaged in genetic research, you surely know of the National Center for Biotechnology Information, a Division of the NIH’s National Library of Medicine. If you’re not familiar with NCBI, I suggest going to their site right now. Get a cup of coffee and set aside some time. You won’t be disappointed.

NCBI maintains several genetics databases, including the world’s largest repository of DNA sequencing data. In 2005, in collaboration with GenBank (Bethesda, Maryland USA), European Molecular Biology Laboratory’s European Bioinformatics Institute (EMBL-Bank in Hinxton, UK), and the DNA Data Bank of Japan (Mishima, Japan), the DNA sequence database topped 100 gigabases (100,000,000,000).

The site also has a set of map viewers that allow readers to compare physical chromosome maps with linkage and sequencing maps.

But for me, your basic general internist, the best feature of the site are its primers on pharmacogenomics and on Clinically important genetic diseases. I was also pleased to see that this site repeats the mantra of this blog: with respect to medications, one size does not fit all!

Here the introduction to their pharmacogenetics page:

Right now, in doctors’ offices all over the world, patients are given medications that either don’t work or have bad side effects. Often, a patient must return to their doctor over and over again until the doctor can find a drug that is right for them. Pharmacogenomics offers a very appealing alternative. Imagine a day when you go into your doctor’s office and, after a simple and rapid test of your DNA, your doctor changes her/his mind about a drug considered for you because your genetic test indicates that you could suffer a severe negative reaction to the medication. However, upon further examination of your test results, your doctor finds that you would benefit greatly from a new drug on the market, and that there would be little likelihood that you would react negatively to it. A day like this will be coming to your doctor’s office soon, brought to you by pharmacogenomics.

Technorati Tags: DNA databases, pharmacogenetics, pharmacogenomics, genetic diseases

It was nine years ago, the significance of which will shortly be revealed. I was attending on the medicine ward service. Our team—myself, a resident and two interns—was on-call every fourth night. If we were lucky, we would manage to squeeze in a few hours of sleep between admissions and pages from the various wards.

At morning report, the interns would present the cases and I would offer comments and a critique. After that, we’d go down to radiology to review any x-rays that accompanied our cases and then we’d go up to the wards to visit the patients. From an academic medical point of view, there were no particularly rare or challenging cases that day, but there was one patient who I could never forgot: Mr. Johnson.

Mr. Johnson was 103 years old, blind and stiff from arthritis, but entirely alert. Mr. Johnson did not have Alzheimer’s. Instead, he was admitted for treatment of a community acquired pneumonia.

When I went to the bedside I felt obliged to draw on my experiences to say something educational both for the housestaff and for the patient, but as we entered Mr. Johnson’s room I was drawing a blank. In the course of this clinical rotation, we’d pretty much discussed pneumonia to the limits of my knowledge. The interns and resident had taken excellent care of Mr. Johnson. He was getting the correct antibiotics and a whiff of oxygen through some nasal prongs. The TV was on, but I could tell he couldn’t see it through his clouded eyes.

“Good morning Mr. Johnson,” I said and I shook his hand. “I’m Doctor Eshleman—one of the doctors who’s taking care of you in the hospital.”

“Hello,” said Mr. Johnson.

“Mr. Johnson, we don’t get many patients as old as you. In fact, I think you’re the oldest patient I’ve ever had. Can I ask you a few questions?” (more…)