A single change in the DNA of mitochondria has been found to cause degenerative heart and muscle disease, according to University of California, Irvine researchers.
“While these diseases traditionally have been assumed to result from mutations in the genes encoded by DNA in the cell’s nucleus, most common degenerative diseases frequently do not exhibit inheritance patterns wholly consistent with our understanding of these nuclear DNA genetics,” explains Douglas Wallace, Ph.D., director of the Center for Molecular and Mitochondrial Medicine and Genetics at UC Irvine and study leader.
The scientists say that they generated a relatively mild mitochondrial DNA mutation in mouse cells. This reduced mitochondrial energy enzyme production by 50%. They then used female mouse embryonic stem cells to create mice in which this mitochondrial DNA energy deficiency mutation was inherited through the female germ line.
Mice harboring the mutant mitochondrial DNA appeared normal early in life but by one year, they developed marked muscle and heart disease, similar to disease that can develop in humans.
“Consequently, mitochondrial DNA mutations and their related energy defects are sufficient to cause age-related disease,” according to Dr. Wallace. “Therefore, mitochondrial energy deficiency may be a common factor in these diseases.”
The study appears in the February 15 issue of Science.