Information about many types of rare diseases and disorders, including causes, symptoms, diagnosis and treatment, including orphan drugs. Site also offers news about rare diseases, orphan drugs, and clinical trials.

Genetics Home Reference (GHR) provides free access to consumer-friendly information on medical genetics to patients and their family members, health care professionals, and the public. The site offers summaries for a broad range of inherited conditions or disorders caused by gene alterations. Each condition summary includes the causes, available genetic testing, and links to summaries on related genes. Descriptions of genes include gene names and their synonyms, normal function, chromosome location, and an explanation of any disorder-causing mutations. Additionally, GHR provides a genetics glossary, help on understanding genetics, and links to many useful consumer, support, and research organizations. GHR is a service of the U.S. National Library of Medicine at the National Institutes of Health.

The eMedicine point-of-care clinical reference features up-to-date, searchable, peer-reviewed medical articles organized in specialty-focused textbooks, and is continuously updated with practice-changing evidence culled daily from the medical literature.

PNHSource.com is leading resource for information, research, and treatment information for Paroxysmal Nocturnal Hemoglobinuria (PNH).

The National Library of Medicine (NLM), on the campus of NIH in Bethesda, Maryland, is the world's largest medical library. It collects materials in all major areas of the health sciences and to a lesser degree in such areas as chemistry, physics, botany and zoology. The collections stand at 5 million items--books, journals, technical reports, manuscripts, microfilms, photographs and images. Housed within the Library is one of the world's finest medical history collections of old (pre-1914) and rare medical texts, manuscripts, and incunabula.