The internet is a superb repository of information about rare and unusual diseases, but the problem is often tracking down the relevant data. There are some highly rated search engines, but a good place to start is rarediseases.info.nih.gov/ord/site-index.html, the site index of the US based Office of Rare Diseases. From here, readers can rapidly assess the relevance of the site to their information requirements. The site also provides links, each with a brief description of the site, to an …