Narod SA. Tamoxifen ChemopreventionâEnd of the Road?. JAMA Oncol. 2015;1(8):1033â1034. doi:10.1001/jamaoncol.2015.2247. Download citation file:
About Rare Diseases. A rare disease is defined by the European Union as one that affects less than 5 in 10,000 of the general population. There are between 6,000 and 8,000 known rare diseases. Around five new rare diseases are described in medical literature each week.
A disease may be considered rare in one part of the world, or in a particular group of people, but still be common in another. Global Genes have estimated that more than 300 million people worldwide are living with one of the 7,000 diseases they define as rare in the United States.