Blogs / 80beats

It’s a mind-boggling piece of medical news: A genetic variant that’s commonly found in people of African descent raises the risk of HIV infection by about 40 percent, but also causes HIV-infected people to live longer. Researchers say the trait is extremely common because it used to have a beneficial effect; it protected people against a form of malaria that is now fairly rare.

The genetic variant may partially account for the high HIV rates in sub-Saharan Africa, where over 24 million people are currently living with the disease. While the differences in HIV prevalence in different parts of the world can be partly explained by different social conditions and sexual behaviour, scientists have long suspected that there may be genetic reasons why the virus is rife in certain communities [BBC News].

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Researchers say they turned a mouse with muscular dystrophy into a mighty mouse by injecting stem cells into its muscles. Just a few weeks after injecting the stem cells, which were taken from the muscles of healthy adult mice, the weak and wasting muscles of the ailing mice were almost completely restored to full strength.

While human trials are still years away, the results offer hope that one day skeletal muscle stem cells from healthy people could be grafted into those with muscle disorders, says Amy Wagers, coauthor of the paper…. People with other kinds of muscle damage could benefit as well, she says. “There are a lot of situations where muscle is degenerating or damaged and you might want to boost its regenerative capacity” [Science News]. 

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Researchers have discovered five new genetic defects that are linked to autism and that appear to share a common function: They’re associated with learning, and are part of a network that allows a child’s brain to build new connections in response to experience [Web MD].

Symptoms of autism typically emerge during the first five years of life — a period when a child normally picks up language, social skills and many other new abilities. Scientists call this kind of growth “experience-dependent learning,” and researchers know that it is associated with enormous changes in brain circuitry. At least 300 genes switch on and off to regulate experience-dependent learning [Time]. Researchers say that the newly identified genes, as well as others already linked to autism, may fail to turn on during this crucial developmental stage, preventing children from learning those social skills and abilities.

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In a few years, young women may be offered a genetic test that would gauge their probability of developing breast cancer decades later. The test, which could be a simple mouth swab, could make women who are at high risk more vigilant and could lead them to detect the disease earlier, researchers say. But some doctors warn the results could cause serious psychological stress and would not identify all women at risk [Sydney Morning Herald].

Researchers know that a woman’s risk of developing breast cancer is based on both genetics and lifestyle. Currently, women with a strong family history of breast cancer are offered genetic screenings, but those tests only look for the rare genes BRCA1 and BRCA2, which have long been known to carry a high risk of the disease. The proposed tests, which researchers say are just a few years away, would also look at seven genetic variants… which have been discovered to increase a woman’s risk of breast cancer, particularly if she has certain combinations of them [The Guardian].

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Fresh veggies and a healthy lifestyle are striking a blow against “genetic destiny.” When a handful of patients with early-stage prostate cancer made dramatic changes to their lifestyles, switching broccoli for red meat and exercising diligently, they made equally dramatic changes to the behavior of their genes.

In a new study, researchers took biopsies before and after the three-month experiment in healthy living, and found that the patients’ lifestyle changes had switched on or off over 500 genes. Some of the changes positively affect genes that help fight cancer, while others help turn off genes that promote cancer development [HealthDay News].

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They were starting to look like the next big thing in biotech. Personal genetics testing companies have been popping up in the last few years, offering regular citizens the chance to pay about a thousand bucks to see their own genomes. The companies say this service can give people insight into their chances of developing inherited diseases and can cast light upon their ancestry, and consumers have begun to plunk down their money.

But now there’s a hitch. Regulators in California sent “cease and desist” letters to 13 companies last week, ordering them to stop offering testing to California residents until they can prove that they have the proper clinical laboratory license, and, more importantly, that each genetics test was ordered by a doctor. The [Public Health Department] said it began investigating gene-testing companies after receiving complaints from consumers “about the accuracy and cost of genetic testing advertised on the Internet” [San Jose Mercury News].

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This is the kind of medical news that always leads to people feeling happy and virtuous as they rush to the nearest liquor store. A new study has just revealed that resveratrol, a compound found in red wine, slowed down the genetic aging of middle-aged lab mice, and appeared to keep their hearts particularly young and healthy.

Of course, resveratrol is also found in grapes, pomegranates, and other foods, and medical researchers still don’t know whether the amount found in a glass of red wine has a clear effect on humans. But the report in the journal Public Library of Science ONE brings enough interesting and promising data to the table to warrant the popping of a few corks.

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The next revolution in health care may be the dawn of “personalized medicine,” where a patient’s genetic makeup is taken into account when prescribing drugs and dosages. A sign of that coming era came over the weekend at an important oncology meeting, where the biotech company ImClone Systems announced that its colon cancer drug was not effective on about 40 percent of patients who have a mutated form of a cell-growth gene.

The trend towards personalized medicine will have repercussions for pharmaceutical companies, who are used to searching for the next blockbuster cancer drug that can benefit a vast number of patients.

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