Trevor's disease — formally known as dysplasia epiphysealis hemimelica (DEH) — is one of the rarest skeletal conditions in existence, with fewer than a few hundred confirmed cases described in the medical literature worldwide.

Kashin-Beck disease occupies an unusual position in medicine. It is geographically concentrated — endemic across parts of Tibet, rural China, and Siberian Russia — yet the biological processes driving it touch on mechanisms that are relevant far beyond those borders: selenium metabolism, selenoprotein function, oxidative stress in cartilage, and mycotoxin exposure from stored grain.