Take the Affliction Test Today!
A Rum and Monkey disease.
Congratulations, you're rickets!
Caused by insufficient phosphorous, vitamin D and/or sunlight, you cause those unlucky enough to suffer you to have swelling in the joints, and bending of the longer bones (such as those found in the legs) in growing children.
You're not very prevalent in affluent societies any more - but don't worry, there's always the third world!