Using a new type of drug that targets a specific genetic defect, researchers at the University of Pennsylvania School of Medicine, along with colleagues at PTC Therapeutics Inc. and the University of Massachusetts Medical School, have for the first time demonstrated restoration of muscle function in a mouse model of Duchenne's muscular dystrophy (DMD).
The research appears ahead of print in an advanced online publication of Nature.
"This new class of treatment has the potential to help a large number of patients with different genetic diseases that have the same type of mutation," says senior author H. Lee Sweeney, PhD, chair of the Department of Physiology at Penn. This genetic flaw causes from 5 to 15 percent (and in a few instances up to 70 percent) of individual cases of most inherited diseases, including DMD, cystic fibrosis, and hemophilia.
The new drug, developed by the South Plainfield, NJ-biotech firm and called PTC124, binds to the ribosome, a cellular component where the genetic code is translated into proteins, one amino acid at a time. The drug allows the ribosome to read through a mistake in the genetic code called a premature stop codon in order to properly make whole proteins.
In DMD, patients are missing dystrophin, a protein that helps keep muscle cells intact. About 15 percent of DMD patients do not make dystrophin because of the mutation. DMD eventually affects all voluntary muscles, as well as heart and breathing muscles.