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    Essential Thrombocythemia

    Important
    It is possible that the main title of the report Essential Thrombocythemia is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.

    Synonyms

    Disorder Subdivisions

    • None

    General Discussion

    Summary
    Essential thrombocythemia, also known as ET, is a rare disease. The most important first fact about ET: on average, people with ET have a normal life expectancy.

    Patients with ET have increased numbers of platelets. Platelets are the smallest of the three types of blood cells and are needed for successful blood clotting after an injury. The two other types of blood cells are red blood cells, which carry oxygen to all tissues in the body, and white blood cells, which help to fight infections. Red blood cell numbers (often measured as a percentage of whole blood, called a hematocrit) are generally normal in ET, while white blood cell numbers are normal or slightly elevated in ET. Importantly, most people with an elevated platelet count do not have ET. Common alternative causes of an elevated platelet count are iron deficiency, infection or generalized inflammation; less common causes are blood disorders such as ET or other related blood diseases (also see below).

    Introduction
    In the 1950's, a pioneering hematologist, William Dameshek, placed ET within a family of blood diseases called myeloproliferative disorders. These were unified by their propensity to lead to abnormal increases in various blood cells, perhaps, in Dr. Dameshek's words, "due to a hitherto undiscovered stimulus". At the time, it was unclear if these "proliferations" represented a natural response to some external cause, or were the result of an internal defect.

    Over time, it became obvious that the myeloproliferative disorders are caused by genetic accidents (an internal defect) in very early blood cells (stem cells), which are then passed along to all of the progeny of that cell, even as they mature into platelets, red cells, or white blood cells (see below). In acknowledgement of this new understanding, myeloproliferative disorders have been renamed myeloproliferative neoplasms (MPN). For this reason, ET is best thought of as a chronic type of leukemia - albeit one with an overall excellent prognosis and often requiring minimal or no treatment.

    Resources

    Leukemia & Lymphoma Society
    1311 Mamaroneck Avenue
    Suite 310
    White Plains, NY 10605
    Tel: (914)949-5213
    Fax: (914)949-6691
    Tel: (800)955-4572
    Email: infocenter@LLS.org
    Internet: http://www.LLS.org

    American Cancer Society, Inc.
    250 Williams NW St
    Ste 6000
    Atlanta, GA 30303
    USA
    Tel: (404)320-3333
    Tel: (800)227-2345
    TDD: (866)228-4327
    Internet: http://www.cancer.org

    NIH/National Heart, Lung and Blood Institute
    P.O. Box 30105
    Bethesda, MD 20892-0105
    Tel: (301)592-8573
    Fax: (301)251-1223
    Email: nhlbiinfo@rover.nhlbi.nih.gov
    Internet: http://www.nhlbi.nih.gov/

    NIH/National Heart, Lung and Blood Institute ~ Hematology Branch
    10 Center Dr, Building 10-CRC
    3-5140, MSC-1202
    Bethesda, MD 20892-1202
    Tel: (301)496-5093
    Fax: (301)496-8396
    Tel: (800)644-2337
    Email: YoungNS@mail.nih.gov
    Internet: http://dir.nhlbi.nih.gov/labs/hb/index.asp?

    Platelet Disorder Support Association
    133 Rollins Avenue, Suite 5
    Rockville, MD 20852
    USA
    Tel: (301)770-6636
    Fax: (301)770-6638
    Tel: (877)528-3538
    Email: pdsa@pdsa.org
    Internet: http://www.pdsa.org

    Genetic and Rare Diseases (GARD) Information Center
    PO Box 8126
    Gaithersburg, MD 20898-8126
    Tel: (301)251-4925
    Fax: (301)251-4911
    Tel: (888)205-2311
    TDD: (888)205-3223
    Internet: http://rarediseases.info.nih.gov/GARD/

    CMPD Education Foundation
    P.O. Box 4758
    Scottsdale, AZ 85261
    Email: ian.sweet@homemail.com.au
    Internet: http://www.mpdinfo.org/CMPD_foundation.html

    Myeloproliferative Disease Support and Daily Email Digest
    2011 Flagler Ave.
    Key West, FL 33040
    USA
    Tel: (305)295-4444
    Email: roberttollen@gmail.com
    Internet: http://www.mpdsupport.org/

    MPN Research Foundation
    180 N. Michigan Avenue, Suite 1870
    Chicago, IL 60601
    Tel: (312)683-7249
    Fax: (312)332-0840
    Email: mwoerhle@MPNResearchFoundation.org
    Internet: http://www.mpnresearchfoundation.org

    MPN Education Foundation
    P O Box 4758
    Scottsdale, AZ 85261
    Tel: (480)443-1975
    Fax: (480)443-1154
    Email: r.niblack@cox.net
    Internet: http://www.mpninfo.org

    For a Complete Report:

    This is an abstract of a report from the National Organization for Rare Disorders (NORD). A copy of the complete report can be downloaded free from the NORD website for registered users. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational therapies (if available), and references from medical literature. For a full-text version of this topic, go to www.rarediseases.org and click on Rare Disease Database under "Rare Disease Information".

    The information provided in this report is not intended for diagnostic purposes. It is provided for informational purposes only. NORD recommends that affected individuals seek the advice or counsel of their own personal physicians.

    It is possible that the title of this topic is not the name you selected. Please check the Synonyms listing to find the alternate name(s) and Disorder Subdivision(s) covered by this report

    This disease entry is based upon medical information available through the date at the end of the topic. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder.

    For additional information and assistance about rare disorders, please contact the National Organization for Rare Disorders at P.O. Box 1968, Danbury, CT 06813-1968; phone (203) 744-0100; web site www.rarediseases.org or email orphan@rarediseases.org

    Last Updated: 5/15/2014
    Copyright 1988, 1989, 1990, 1995, 1997, 1998, 2002, 2004, 2005, 2008, 2012, 2014 National Organization for Rare Disorders, Inc.

    WebMD Medical Reference from the National Organization for Rare Disorders

    Last Updated: May 28, 2015
    This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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