17 June 2013

Will studying a rare mutation help defeat obesity?

A man without fat

Nadezhda Markina, "Newspaper.Ru"Scientists have found a mutation responsible for the rare and mysterious illness of Paralympic athlete Tom Staniford, whose body is not able to store subcutaneous fat at all.

Now we can hope that sooner or later doctors will be able to cure him. Well, until that happens, the discovery will allow him to become a world champion, since he will be able to correctly classify at the Paralympic competitions.

British Paralympian cyclist Tom Staniford suffers from a rare disease that still baffles doctors. The 23-year-old athlete looks extremely exhausted: his body is not able to store subcutaneous fat at all. Due to his incredible thinness, his body is unable to absorb shocks and the risk of limb fractures is high, and besides, he constantly suffers from cold. Tom Staniford was born with a normal weight, but in childhood and adolescence he lost all the subcutaneous fat from his face, arms and legs. At the same time, his hearing began to deteriorate progressively, and now he wears hearing implants. Finally, the disease led to the fusion of some bones in his limbs.

Oddly enough, Tom's body believes that he is obese, because his blood is constantly high in fat. A rare disease is also accompanied by type 2 diabetes.

Tom Staniford struggles with his diabetes with medications and a strict diet. But during training, the athlete reduces the dose of medication, since intense physical activity allows the body to independently control the level of insulin. Tom has several victories in cycling races of different levels, he is a member of the national Paralympic team of Great Britain.

Finally, an international team of researchers, coordinated by specialists from the University of Exeter Medical School, found the cause of the athlete's rare illness. After conducting a complete sequencing of its genome, scientists discovered a mutation that causes the so-called MDP syndrome. The researchers published the results of their work in the journal Nature Genetics on Monday night (Weedon et al., An in-frame deletion at the polymerase active site of POLD1 causes a multisystem disorder with lipodystrophy).

Professor Andrew Hattersley worked with Tom for several years. He leads an international team of researchers who are studying four patients in the UK, USA and India with similar symptoms. None of them has a family history of the disease, so scientists have suggested that the disease is caused by a spontaneous mutation, which neither parent has.

"We studied 3 billion nucleotides–Tom, his relatives and other patients — and found a key mutation," Hattersley said. "This is an example of how progress in genomic technologies makes it possible to determine the cause of unusual, extremely rare diseases."

The mutation was found in the POLD1 gene, in the 19th chromosome of all patients. The absence of one amino acid led to a defect in the enzyme DNA polymerase, which plays a key role in DNA replication. This led to such serious disorders in metabolism and, ultimately, in anatomy.

Accurate diagnosis of the disease is very important for Tom Staniford, as previously some experts believed that he had progeria — a genetically determined abnormally rapid aging of the body, ending in an early death. Now he knows that's not the case. But the cyclist considers the result to be no less important for his sports career. An accurate diagnosis can help him win the Paralympics.

"This will allow me to be properly classified at the Paralympic competitions," Tom Staniford said. "I hope that I will participate in the British national team at the 2016 Paralympic Games in Rio de Janeiro, and I have a real chance of winning."

Professor Hattersley and his colleagues believe that by identifying the genetic breakdown that leads to MDP syndrome, it will be possible to find a cure for its correction in the future. Then it will be possible to alleviate the condition of all patients suffering from this disease. In addition, the expert believes, the discovery of a mutation that prevents fat from accumulating will allow for a better understanding of the causes of the opposite condition – when there is too much fat. And this is relevant for a much larger number of people.

Portal "Eternal youth" http://vechnayamolodost.ru17.06.2013

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