New genetic cause of an inherited neuropathy discovered

A discovery by Penn researchers in siblings may hold answers to new gene therapies for Charcot-Marie-Tooth disease.

Inherited mutations in a gene that keeps nerve cells intact was shown, for the first time, to be a driver of a neuropathy known as Charcot-Marie-Tooth (CMT) disease. This finding is detailed in a study led by researchers in the Perelman School of Medicine, which published in Neurology® Genetics, an official journal of the American Academy of Neurology.

Three renderings of illustrated brains, one is an abstract scribble, one looks cloudy and ephemeral, one looks like plant matter.

The findings, thanks to siblings treated at Penn since the late 1980s, present a clearer picture of the disease’s genetic underpinnings that could inform the development of gene therapies to correct it.

The mutations in the gene known as dystonin (DST) add to a growing list of malfunctions found to cause their type of CMT, known as CMT2, which is defined by the loss of the nerve fibers, or axons, in the peripheral nerve cells. The researchers also showed that these mutations affect two key protein isoforms, BPAG1-a2 and BPAG1-b2, that are involved in nerve fiber function. Mutations in other isoforms of the same protein were previously tied to a blistering skin disease.

There are more than 100 mutations found to be associated with CMT, with likely many more out there. Past studies from Penn researchers have identified some of these mutations by studying patients treated at Penn Medicine.

“We are determined to fill in the blanks of this giant jigsaw puzzle,” says senior author Steven S. Scherer, a professor of neurology. “This latest paper is but one of many examples of where breakthroughs have happened between patients and the doctors at Penn and the support of different organizations and institutions to bring it all together."

Read more at Penn Medicine News.