Welcome to the official rare disease educational website developed by The National Organization for Rare Disorders. By raising awareness of rare diseases among physicians, clinicians and other medical professionals, NORD strives to help patients obtain earlier diagnosis and appropriate treatment. Learn more >
A rare disease is one that affects fewer than 200,000 Americans at any given time.
According to the National Institutes of Health, there are between 6,000 and 7,000 rare diseases affecting from 25 to 30 million Americans.
Approximately 50% of the people affected by rare diseases are children.
Since 1983, more than 2,200 rare disease treatments have entered the research pipeline and more than 360 have been approved for marketing.
NORD Physician Guides
Guide Index
Latest Guides
+ Amyloidosis
+ Hereditary Angioedema
+ Homocystinurias
+ Lipodsytrophy Disorders
+ Myelofibrosis
+ Pompe Disease
+ Treacher Collins Syndrome
+ Tyrosinemia Type 1
+ Urea Cycle Disorders
For additional information on over
3,000 other rare diseases visit
NORD's Rare Disease Database >
Pompe Disease
Pompe disease is an autosomal recessively inherited metabolic disorder that affects one of more than 40 lysosomal enzymes. Pompe disease can present in infancy, childhood, adolescence or adulthood.
View Guide >
Myelofibrosis
Myelofibrosis (MF) is categorized as a chronic myeloproliferative neoplasm (MPN). This is a group of heterogeneous, hematopoietic stem-cell malignancies.
View Guide >
Lipodystrophy Disorders
Lipodystrophies are disorders characterized by selective loss of adipose tissue (body fat) from various regions of the body. These disorders may be either inherited or acquired.
View Guide >
Urea Cycle Disorders
The urea cycle disorders are hereditary metabolic disorders caused by a deficiency of one of the enzymes in the urea cycle responsible for removing ammonia from the bloodstream.
View Guide >