'The right diagnosis is unbelievably powerful': It can take years to diagnose rare diseases, and scientists are trying to fix that

Millions of Americans are diagnosed with common conditions like cancer and diabetes — but some 10% of the population live with rare diseases that doctors often struggle to diagnose. On average, those with rare diseases will spend five to seven years searching for answers and see 12 specialists before they arrive at a diagnosis.

In the process, they may be subject to incorrect, ineffective or even harmful treatments.

"Any medicine that you prescribe has a one-third chance of working, a one-third chance of doing nothing, and a one-third chance of hurting you," said Dr. Ada Hamosh, a geneticist and the center director for the Johns Hopkins Medicine-Kennedy Krieger Institute National Organization for Rare Disorders (NORD) Rare Disease Centers of Excellence Network. "I do not want to understate this: The right diagnosis ...