Breakthroughs on rare neurologic disease.

• Position: CADASIL - Brief article

In fall 2013, a French neurologist who identified the gene responsible for a rare small vessel disease in the brain, CADASIL, approached University of Vermont, Burlington, researcher Mark Nelson after a workshop honoring the 20th anniversary of her discovery. She expressed frustration that she had nothing new to offer her patients about the mechanisms and progression of CADASIL --Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy--after two decades.

In the two-plus years since Nelson had that discussion with Marie-Germaine Bousser, neurology chief at Hospital Lariboisiere in Paris, France, he and an international research team studying CADASIL and other small artery diseases are uncovering what occurs in the brains of people born with the genetic mutation of a protein known as Notch3. "It's a cascade of things that happen afterward," says Nelson, distinguished professor and chair of pharmacology.

CADASIL is rare, affecting about one in 50,000 people, but the researchers' insights inform the study of stroke and dementia.

The researchers found that they can...