With the advent of genomics, diseases that were once grouped based only on clinical descriptions are now being understood more precisely as different rare diseases.

"Everyone wants to find a rare disease that can also be used for a majority of the population," Lin said. "Many blockbuster drugs started off as rare indication. If you have something working for one disease, you want to try it for others as well." He added, "The drug pipeline for common diseases is drying out, so pharma companies are trying to get creative here."

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