An Associated Press story this week spotlights a fascinating phenomenon occurring in the wake of drug companies’ reluctance to do research on exceedingly rare diseases. In the article, we meet twins Addison and Cassidy, whose Nevada mother worked to make sure the kids get an experimental medicine injected into their spines. The 7-year-old girls have a fatal disease, but one so rare that it has generated little research for a treatment.

There are treatments for roughly 200 of the roughly 7,000 rare diseases, which are defined as illness that affect less than 200,000 people. “Yet add those diseases together,” reports AP, “and more than 20 million Americans have one.”

From grass-roots efforts to the recently introduced Creating Hope Act in our nation’s Capitol, there is a concerted – and perhaps long-overdue – push to spur research for rare disease.