Primary Myelofibrosis

What is primary myelofibrosis?

Primary myelofibrosis is a rare, chronic form of leukemia and a bone marrow disorder. When an individual has primary myelofibrosis, a single hematopoietic stem cell’s DNA is changed, causing it to continually make copies of itself, eventually pushing out the normal, healthy cells. Coupled with the fibrosis, bone marrow fails to produce enough normal blood cells. Primary myelofibrosis typically occurs in people greater than 50 years of age, though it can happen at any age. While the incidence of primary myelofibrosis is not completely known, it affects approximately one in 500,000 people worldwide and occurs in men and women equally. If the disease does affect a child, it occurs twice as often in girls than boys and before the age of three.

What are the symptoms of primary myelofibrosis?

Primary myelofibrosis symptoms may not show right away. But as the normal cells are pushed out, primary myelofibrosis may manifest itself in the following ways:

• Anemia
  • Fatigue
  • Shortness of breath
  • Weakness
  • Lightheadedness
  • Pale skin
  • Headaches
  • Irritability
• Fever
• Night sweats
• Frequent bacterial/fungal infections
• Excessive bruising
• Excessive bleeding from the gums and nose
• Enlarged spleen, causing pain or fullness below the left ribs
• Enlarged liver
• Tumors in the GI tract, lungs, skin, liver, spleen, etc.
• Bone and joint pain

What causes primary myelofibrosis?

Primary myelofibrosis is caused by a genetic mutation, though it is idiopathic, and the genetic mutation occurs without a known reason.  While their role in primary myelofibrosis is not known, there are specific genes mutated in people with primary myelofibrosis: 50% have a mutation in the JAK2 gene, 20% have one in the CALR gene and 10% have one in the MPL gene. Ultimately, the mutated cells reproduce rapidly, outnumbering healthy cells. The scarring (fibrosis) in the normally spongey bone marrow also impedes healthy cell production, causing a shortage of red blood cells and an increase in white blood cells and platelets.

How is primary myelofibrosis diagnosed?

Primary myelofibrosis is diagnosed using the following procedures:

• Blood testing: Complete blood count (CBC) looking for abnormal amounts of red and white blood cells and platelets
• Physical examination
• Imaging: X-rays and MRIs
• Bone marrow examination
• Genetic testing

What treatment options are available for primary myelofibrosis?

Primary myelofibrosis treatment includes, but is not limited to:

• Gene therapy
• Ruxolitinib, the only FDA approved drug right now, but more are being developed in clinical trials
• Anemia treatment
  • Blood transfusions
  • Androgen therapy
  • Thalidomide, lenalidomide and/or pomalidomide, occasionally combined with steroids
• Splenectomy (Removing of the spleen)
• Chemotherapy
• Radiation
• Stem cell transplant
• No treatment
  • Some patients are asymptomatic, so doctors just monitor symptoms

Where can I find out more about primary myelofibrosis?

• National Organization for Rare Disorders (NORD)
• Mayo Clinic
• NIH