A scientific team that included researchers from Europe, the University of Rochester and Seattle has worked out how a curious genetic mutation may cause a common form of muscular dystrophy.
People with the condition, called facioscapulohumeral muscular dystrophy or FSHD, develop muscle weakness starting in face, shoulders and upper arms.
The weakness tends to appear when a person reaches his or her teens, grows more severe with time and can eventually spread to other muscle groups. Severity can range from mild to disabling.
The findings of the new study may someday lead to a treatment for the disease.
Silvère M. van der Maarel, professor of medical epidgenetics at Leiden University Medical Center led the study in collaboration with Dr. Rabi Tawil, M.D. of the University of Rochester Medical Center and Dr. Stephen Tapscott of the Division of Human Biology at the Fred Hutchinson Cancer Research Center. Dr. Daniel Miller of the University of Washington was also on the research team.
The search for the gene
Early genetic studies indicated that the gene causing FSHD was located at the end of chromosome 4. But it was not clear exactly where the gene was.
One area of interest was a structure at the end of the chromosome called a macrosatellite repeat array. These arrays are composed of the same sequence of DNA repeated over and over again.
Such arrays occur commonly in our chromosomes, but are usually inactive.(to learn more, read this article)