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Genetic and Rare Diseases Information Center (GARD)

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Other Names for this Disease
  • Agnogenic myeloid metaplasia
  • Idiopathic myelofibrosis
  • Myeloid metaplasia
  • Primary myelofibrosis
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Your Question

I need to ascertain the incidence of myelofibrosis in the United States. I would also like to know if the Office of Rare Diseases (ORD) at the National Institutes of Health (NIH) lists myelofibrosis as a rare disease. 

Our Answer

We have identified the following information that we hope you find helpful. If you still have questions, please contact us.

What is myelofibrosis?

Myelofibrosis is a disorder of the bone marrow, in which the marrow is replaced by fibrous (scar) tissue.[1] Scarring of the bone marrow causes anemia, which can lead to fatigue and weakness, as well as pooling of the blood in abnormal sites like the liver and spleen, causing these organs to swell.[1][2] Although myelofibrosis can occur at any age, it typically develops after the age of 50.[1][2] In most cases, myelofibrosis gets progressively worse. Treatment is aimed at relieving signs and symptoms and may include medications, blood transfusions, chemotherapy, radiation therapy and surgery.[2]   
Last updated: 8/17/2011

What is the incidence of myelofibrosis in the United States?

Few epidemiologic studies are available to estimate the incidence of myelofibrosis.[3] Through the review of several medical textbooks, it appears as if the annual incidence rate in European, Australian, and North American populations ranges from 0.3 to 1.5 cases per 100,000 persons.[3][4][5]  

Last updated: 1/7/2009

Does the Office of Rare Diseases (ORD) at the National Institutes of Health (NIH) list myelofibrosis as a rare disease? 

Yes, myelofibrosis is included on the Office of Rare Disease's list of rare diseases and related terms.
Last updated: 1/7/2009

  • Dugdale DC, Mason JR. Primary myelofibrosis. MedlinePlus. July 11, 2008; Accessed 1/7/2008.
  • Myelofibrosis. February 1, 2007; Accessed 1/7/2008.
  • Hoffman R, Ravandi-Kashani F. Chapter 70 - Idiopathic Myelofibrosis. Hematology: Basic Principles and Practice, 4th edition. Philadelphia, PA: Elsevier; 2005;
  • Tefferi, A. Chapter 177 - Myeloproliferative Disorders: Essential Thrombocytopenia and Primary Myelofibrosis. Cecil Medicine, 23rd edition. Philadelphia, PA: Elsevier; 2007;
  • Tefferi A. Chapter 106- Myeloproliferative Disorders. Abeloff's Clinical Oncology, 4th edition. Philadelphia, PA: Elsevier; 2008;