Orphan diseases are rare diseases whose prevalence is low, between 1/1 and 1/200 000 000 inhabitants according to national definitions. To date, it is estimated that between 5000 and 8000 rare diseases.
Added to this criterion an absence of effective treatment.
Five new rare diseases are described every week in the world. 6-8% of the world population would be affected, directly or indirectly, by these diseases, so 4 million French, 25 million Europeans and 27 million North Americans.
65% of rare diseases are serious and disabling.
Cystic fibrosis is one of the orphan diseases