“When you hear hoofbeats, think horses not zebras,” is a saying well known to young doctors to remind them to think of the most common and likely diagnosis when assessing a patient. However, if a clinician is not that familiar with rare conditions, they may struggle to treat the horse when they should have diagnosed a zebra all along.
It is thought that around 350 million people are affected by undiagnosed genetic diseases, outnumbering people living with cancer and AIDS combined. There are more than 10,000 rare diseases that...
