There are more than 7000 rare diseases, also called orphan diseases. How does one decide the threshold for considering a disease to be rare? It depends. One study found more than 296 definitions of “rare disease.” In Europe, a disease is typically considered rare if it affects fewer than 1 in 2000 people, but the most widely used definitions place rare diseases as those that affect 4 or 5 out of 10,000 people. But in today's world of population growth and virtual communities, in many ways rare diseases are becoming common. 

By Melissa A. Wilson Sayres
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“ Do you feel tired ?” asks the silver fox in his outdoor jacket, wind in his hair. He then suggests that you may suffer from low testosterone, which apparently is a serious condition that could be impacting “millions of men.” Evidently the solution, he suggests, is just a...
By Benjamin Trumble
The greatest advance in entire history of medicine was recognition that bodies are machines assembled entirely from material substances. Now, however, the metaphor of body as machine is an obstacle to progress. To understand the body as a body, we need to blow the metaphor away...
By Randolph M. Nesse
This week is the 2nd annual meeting of the International Society for Evolution, Medicine, and Public Health . The presentations we'll see, and the conversations we’ll have, were instigated 25 years ago as George Williams and I discussed and grappled with how evolution could be...
By Randolph M. Nesse
In December 2013, in the village of Meliandou, Guinea, a dangerous pathogen jumped from a bat into a little boy. He may have been playing among the trees where bats roost, coming into contact with bat guano; the details are uncertain. But several days later, as the pathogen...
By Anne Stone