A critical advance in determining the cause of a common form of muscular dystrophy known as facioscapulohumeral dystrophy, or FSHD has been made by scientists.
They have identified a DNA sequence in individuals with FSHD that causes a gene called DUX4 to be more active.
Previous work from this research team and others has shown that this gene produces a protein that is toxic to muscle cells, and the current study indicates that it is likely to be key to developing FSHD. This finding points to potential new drug targets for treating - or potentially curing - FSHD, a progressive condition characterized by progressive wasting of muscles in the upper body.
The findings shed new light on how a genetic mutation identified nearly 20 years ago causes the disease.
Researchers at the University of Leiden led the study in collaboration with co-authors Stephen Tapscott, Dan Miller of the University of Washington and Rabi Tawil.
"In contrast to most genetic diseases, knowledge of the genetic mutation did not explain the cause of the disease," said Tapscott.
"These new findings provide a single, testable hypothesis," he said.
The research group identified a DNA variation, or polymorphism, necessary for FSHD that occurs near the mutation region on chromosome 4 that was discovered nearly two decades ago.
In those susceptible to this form of muscular dystrophy, this DNA mutation stabilizes the product of the DUX4 gene and thus causes the gene to be more active.
"This provides a new and unifying model for FSHD because it will focus future research on determining whether the DUX4 protein causes FSHD, as indicated by our consortium's genetic analysis," Tapscott said.
The findings were published in the journal Science.