In a first, Huntington’s disease is slowed by an experimental treatment

Even hearing the phrase “Huntington’s disease” will make a room suddenly somber. So the joy that accompanied a recent announcement of results of an experimental gene therapy for the deadly diseases signaled an unfamiliar sense of hope.

In a small clinical trial, brain injections of a virus that codes for a tiny segment of RNA may have prevented the formation of the rogue proteins that make Huntington’s so devastating. The early results, announced September 24 in a news…