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Vol. LIX, No. 10
May 18, 2007

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  Whippets are able to sprint to speeds approaching 40 miles per hour.<br><br><span class=byline  style='font-size:100%; color:#000000'>Photo: Tyrone Spady, NHGRI</span>  
  Whippets are able to sprint to speeds approaching 40 miles per hour.

Whippets, Whippets Good (or at Least Fast)

Last month, NHGRI identified a genetic variant that contributes to dog size; now, they’ve moved on to speed. In a study published online in PLoS Genetics on May 1, researchers reported that a mutation in a gene that codes for a muscle protein called myostatin can increase muscle mass and enhance racing performance in whippets, the sprinting dogs that resemble small greyhounds. This finding can help explain why some whippets— known to clock speeds of close to 40 miles per hour—run even faster than others: the fastest dogs inherited a mutated copy of the myostatin gene from one parent and a normal copy from the other. However, some mutation is better than a lot. Whippets with two mutated copies have a gross excess of muscle and are prone to shoulder and thigh cramping, making it hard for them to join a race.

Diabetes Milestones

More genetic news: a landmark study led in part by NHGRI director Dr. Francis Collins and supported by NIDDK and NHGRI’s Division of Intramural Research reported the identification of at least four new genetic variants associated with increased risk of type 2 diabetes; they also confirmed the existence of another six variants. The findings were published simultaneously by three groups (a U.S.-Finnish team, the international Diabetes Genetics Initiative and a British team) in the Apr. 26 online edition of Science, and could point researchers in the direction of new drug targets for the prevention and treatment of the disease, which affects close to 21 million people in the United States.

DNA Repair and Huntington’s Disease

Meanwhile, a study funded by NIGMS, NINDS and NIEHS linked faulty DNA repair to the onset of Huntington’s disease. In an advanced online publication of Nature, the study points to a potential way to stop or slow the onset of this inherited, incurable and fatal neurodegenerative disorder that affects around 30,000 Americans. The disease’s symptoms don’t usually appear until middle age, so scientists have long wondered what triggers it and how it can be stopped or slowed down. They do know that people with Huntington’s have a version of a gene named huntingtin that carries an extra segment. If that segment is too large, the gene produces a faulty protein that can harm the brain. And though it’s still a mystery why exactly Huntington’s progresses, the researchers say their findings—conducted on mice—support the idea that the disease advances when the extra segment expands over time in non-dividing cells, such as nerve cells. These insights on how the disease arises could point to the development of new treatments and prevention methods for Huntington’s in the future.

The Brain and Alzheimer’s

According to an imaging study by NIMH researchers, a part of the brain first affected by Alzheimer’s disease is thinner in youth with a risk gene for the disorder. The research, published in the June issue of Lancet Neurology, shows that having a thinner entorhinal cortex, a structure in the lower middle part of the brain’s outer mantle, could make these children and teens more susceptible to degenerative changes and mental decline later in life. The study reports that a variation in apolipoprotein, a gene that plays a critical role in the repair of brain cells, affects the development of the entorhinal cortex. However, only long-term brain-imaging studies of healthy aging adults will be able to confirm whether this early thinning predisposes someone for Alzheimer’s, researchers said.

Hold the Salt, Keep the Nuts

New clinical data from NHLBI shows that redu-cing sodium intake prevents not only high blood pressure, but also heart disease. The study, published online Apr. 20 by the British Medical Journal, reported that men and women with pre-hypertension who reduced their sodium intake by 25 to 35 percent had a 25 percent lower risk of total cardiovascular disease over the 10 to 15 years following their sodium intake reduction. Participants were able to lower sodium intake through dietary and behavioral intervention; data from follow-up questionnaires found that many of the dietary changes were long-lasting. On a side note, while you’re reducing sodium, you may not want to cut out macadamia nuts: a study from Penn State supported in part by NIH found that a daily diet containing 1.5 ounces—a small handful—of the Hawaiian treat reduced total cholesterol, low-density lipoprotein cholesterol and triglyceride levels compared with a standard American diet. —

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