WEDNESDAY, Jan. 26 (HealthDayNews) -- A new form of muscular dystrophy that develops after age 40 and causes limb weakness along with nerve and heart muscle damage has been identified by Mayo Clinic scientists.

They named this new form zaspopathy and said this finding increases the understanding of the muscular dystrophy disease process and the role that genes play in it. That knowledge could help in efforts to find a cure.

The study appears in the Jan. 26 online version of the journal Annals of Neurology.

This newly defined form of muscular dystrophy can be caused by any one of three mutations in a gene responsible for giving instructions for a protein called ZASP, the study found. The genes involved in zaspopathy are passed from parents to children in a dominant manner -- meaning that a child will develop the disorder by receiving one copy of the mutant gene from one parent.

The Mayo team made the finding using information gleaned in laboratory work combined with clinical data from a large patient base.

"The fact that we could pull together all different types of data and that it all pointed to the ZASP protein was key to the success of this effort," study leader and neurologist Dr. Duygu Selcen said in a prepared statement.

Approximately 50,000 Americans have muscular dystrophy, a group of genetic diseases characterized by progressive weakness and muscle degeneration. There is no cure, but therapies can slow its course.

More information

The Cleveland Clinic Foundation has more about muscular dystrophy.