Talk

New, Promising Treatments for Cystic Fibrosis. Forbes has a long article on two drugs, Inspire and Vertex, that are in late stage clinical trials. The article has a great explanation of how cystic fibrosis on a cellular level causes its symptoms - breathing, lung, and digestive problems. (Forbes online is free, but they require registration)

Affymetrix to Launch a 1 Million-SNP Microarray. The new GeneChip will debut early next year, at around $500. Affy is also dropping the price of its 500,000-SNP genotyping to $250. More heralds of the fast-approaching age of affordable genotyping.

Couples Select Embryos to Halt Inherited Cancer. Part of the NY Times’ series, “The DNA Age,” this article explains how preimplantation genetic diagnosis, or PGD, can avoid the tranmission of fatal conditions like Huntington’s Disease as well as significant cancer risk genes, as the family profiled in the article chose to do. This technology and the use of it raises ethical issues and has many talking about what it means that this technology may only be accessed by those with the significant financial means. The Times, as usual, has a balanced discussion.

Update: A Genetic Code for Breast and Colon Cancer. The first draft is in, and The Biotech Weblog has the scoop. This is very exciting! The promise lies in both detection (with tests like PreGen Plus) and with targeted treatment.

Technorati Tags: cystic fibrosis, clinical trials, genotyping, genetic testing, GeneChip, preimplantation genetic diagnosis, huntington’s disease, inherited cancers, breast cancer, colorectal cancer, diagnosis, treatment

Last week, the Senate Committee on Aging had a very public hearing on nutrigenomic testing, four Internet-based companies that offer it, and regulations for at-home genetic tests. The hearing was prompted by a probe conducted by the US Government Accountability Office (GAO).

Interestingly, my colleague Jason was pointing out these issues three years ago, when some of these companies began offering their services. He said, “…nutritional profiling remains a concept under study and is not ready for mainstream consumption.”

In November 2003, Nature ran Erika Check’s article “Consumers warned that time is not yet ripe for nutrition profiling”:

But many scientists argue that it’s far too early for most of these tests to be useful. “The idea of marketing any individual genetic test at this point assumes there is information to justify the use of that test, and we really don’t have evidence that any single genetic marker carries enough information to guide dietary treatments,” says Ronald Krauss, director of atherosclerosis research at CHORI.

Today in Nature, Gene Russo’s article “Home health tests are ‘genetic horoscopes’” provides a tidy bookend:

Advocates of testing point out that the dubious nutrigenetic tests are very different to legitimate, reliable at-home tests for diseases such as cystic fibrosis.

What’s the difference? A key issue that consumers need to look for when considering genetic tests: clinical accuracy, clinical validity, and clinical utility. They mean different things, and for someone considering genetic testing - at-home or otherwise – all three are very important.

Clinical accuracy, also called analytic validity, is the measure of a test’s performance. If a test is looking to see if you carry a particular DNA sequence, clinical accuracy is the degree to which the test will reliably identify that DNA sequence (or the lack thereof). For example, cystic fibrosis testing is over 99% accurate as conducted in certified laboratories. More than 99 out of 100 times, the test won’t incorrectly identify a DNA sequence.

Clinical validity has to do with what a test means. Knowing the DNA sequence isn’t enough; we need to know the degree to which the DNA identifies or predicts a particular condition in order for the test to be meaningful. With cystic fibrosis, we know that if someone inherits two known mutations in the CFTR gene (one from each parent), they will have cystic fibrosis.

Clinical utility. This is the degree to which we can do something in response to knowing about our DNA sequence. If we’ve got a clinically valid test result, we can do things like take preventive steps, make lifestyle decision, choose effective treatment options. If you and your partner are both carriers of CF mutations, you can understand your odds of having a child with CF and make family planning decisions accordingly.

A few other points in this GAO discussion that deserve clarification:

• Not all at-home genetic tests are nutrigenomic tests. There are at-home tests available for clinically valid tests, such as cystic fibrosis, that are recommended under certain circumstances by medical guidelines from physician organizations.

• Not all nutrigenomic tests are direct-to-consumer or at-home. Some tests are being offered at wellness clinics and through alternative medicine practitioners, nutritionists, and other healthcare providers.

I think the bottom line is, as with any decision regarding healthcare choices and medical treatments, be smart. Do your research. Consult with your doctor or doctors (second opinions are never a bad thing). If you’re looking for a miracle pill or a crystal ball, you’re probably not going to find it.

Read more:

• Time magazine’s coverage
• Companies targeted in the GAO probe: Sciona, Suracell, Genelex, Market America
• DNA Direct’s philosophy about all this

Technorati Tags: nutrigenomics, nutrigenetics, nutrition, genetics, genetic testing, direct-to-consumer

Why be aware of cystic fibrosis? As many as 1 in 25 people in the US is a CF carrier. And that’s a pretty high carrier rate for a condition that most people don’t know about.

Cystic fibrosis, or CF, is an inherited disease that affects the lungs, digestive system, sweat glands, and male fertility. If you are pregnant - or thinging about getting pregnant - you should know about CF.

You might be suprised to know:

• A simple genetic test can help you find out if you are a carrier. If you are, you can figure out your chances of passing on that CF mutation to a child. If your partner is also a carrier, you have a 1 in 4 chance of having a child with CF.
• CF occurs in all ethnic groups, but people with European or Ashkenazi Jewish ancestry are more likely to be carriers than others.
• CF mutations can be passed down “silently” for many generations, without anyone in the family ever having CF.
• This is why medical guidelines say that everyone who is pregnant or planning a pregnancy — and everyone with Caucasian ancestry — should be offered CF carrier screening.
• In rare instances, people with frequent lung infections or chronic sinusitis are diagnosed late in adulthood as having CF. (Most people don’t hear about “mild” CF.)
• There are over a 1000 known CF mutations, and scientists are learning more about what they mean every day. Treatments are continually in development, and people with CF are living longer and healthier lives than before.

Want to learn more or spread the word about CF? The Cystic Fibrosis Foundation is a great resource that has been providing information, support and advocacy for 51 years. (Here are more resources.) Looking for support? The Lawrences are a family blogging about their experiences of raising their children, including a daughter with CF.

Technorati Tags: cystic fibrosis, CF, carrier screening, genetic testing, pregnancy, disease