Can what is done be undone? In a part answer to that adage researchers have announced the developing of a miracle drug to treat genetic disease- those which one is born with and which usually is not correctable.
Obviously the scientific world is too thrilled for silence. The drug named as PTC124 and been worked upon by researchers from PTC Therapeutics in New Jersey and those from University of Pennsylvania and Massachusetts , is slated to be licensed for public use by 2009.
AdvertisementThe drug which trains the crosshairs on diseases caused by faulty genes, has been so far successful on Duchenne muscular dystrophy (DMD) and cystic fibrosis. The drug is being tested on humans now after promising results on mice and researchers hope it could eventually be used to treat sufferers of around 2,000 other types of hereditary disease.
DMD is known to afflict one in 3,500 boys and is marked by weakness and muscle wasting. Children born with cystic fibrosis suffer digestion and respiratory problems and tend to die early. Both these conditions are caused by so-called "nonsense mutations" in the child's DNA meaning that the sufferer lacks a vital protein.
Accordingly, in most genetic conditions, between 5-15 per cent of cases are caused by a defect called a "nonsense mutation".
Genes are instruction manuals for cells to make proteins, but nonsense mutations in effect introduce a command halfway through that stops production. The kind of protein disrupted determines the nature of the disease.
In Duchenne muscular dystrophy, for example, the protein necessary for normal muscle development is not made, and the fatal wasting disease is the result. In hemophilia, it is the gene for the clotting agents factor VIII or factor IX that is disrupted.
Till now no known cure for either CF or DMD and sufferers rarely live beyond their 30s. Yet now the researchers have announced that mice suffering from a form of DMD began growing new muscles - after being treated with a the drug.
Says lead researcher Lee Sweeney, who is leading the research: " There are literally thousands of genetic diseases that could benefit from this approach. "What's unique about this drug is it doesn't just target one mutation that causes disease, but a whole class of mutations."
So how does the drug work? PTC124 works by binding to a part of the cell called the ribosome, which translates genetic code into protein, and allowing it to ignore nonsense mutations. The gene can be read straight through and a normal protein is produced. According to the report published in the journal Nature, the drug is already being tried out on 100 humans.
At the same time PTC124 is just one of a new generation of treatments which are bringing hope to sufferers of the genetic disease cystic fibrosis, such as gene therapy. Professor David Porteous at the Edinburgh University is pioneering this. Porteous hailed the announcement of PTC124 as "very exciting". "It will be very important to see if this exciting new drug can be used safely and effectively in the clinic," he was quoted. "But PTC124 or similar products could only ever be a small part of the solution as the vast majority of CF patients have a different type of mutation from the rare nonsense mutation which is specifically targeted by this class of compounds. Gene therapy is the obvious best hope."
Gene therapy involves manufacturing a fully working version of the cystic fibrosis gene and introducing it into the cells lining the lung where it is needed.
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