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Genetics Home Reference: your guide to understanding genetic conditions     A service of the U.S. National Library of Medicine®


Reviewed September 2014

What is the official name of the THPO gene?

The official name of this gene is “thrombopoietin.”

THPO is the gene's official symbol. The THPO gene is also known by other names, listed below.

What is the normal function of the THPO gene?

The THPO gene provides instructions for making a protein called thrombopoietin that promotes the growth and division (proliferation) of cells. This protein attaches to (binds) and turns on (activates) the thrombopoietin receptor, which stimulates several signaling pathways that transmit chemical signals from outside the cell to the cell's nucleus. These pathways are important for controlling the production of blood cells.

Thrombopoietin is especially important for the proliferation of certain blood cells called megakaryocytes, which produce platelets, the cells involved in blood clotting. Research suggests that thrombopoietin signaling may also play a role in the renewal of hematopoietic stem cells, which are stem cells located within the bone marrow that have the potential to develop into red blood cells, white blood cells, and platelets.

Does the THPO gene share characteristics with other genes?

The THPO gene belongs to a family of genes called endogenous ligands (endogenous ligands).

A gene family is a group of genes that share important characteristics. Classifying individual genes into families helps researchers describe how genes are related to each other. For more information, see What are gene families? ( in the Handbook.

How are changes in the THPO gene related to health conditions?

essential thrombocythemia - associated with the THPO gene

Several mutations in the THPO gene have been found in people with essential thrombocythemia, a condition characterized by an increased number of platelets in the blood. Because platelets are the blood cells involved in blood clotting, abnormal clotting (thrombosis) is common in people with essential thrombocythemia.

THPO gene mutations are found in families with an inherited form of the condition called familial essential thrombocythemia. These mutations affect a region of the gene that usually blocks (inhibits) the production of the thrombopoietin protein (a process called translation). THPO gene mutations lead to increased translation of the protein. The excess protein can abnormally activate the thrombopoietin receptor and the signaling pathways, leading to overproduction of megakaryocytes and increased numbers of platelets. Excess platelets can cause thrombosis, which leads to many signs and symptoms of essential thrombocythemia.

Where is the THPO gene located?

Cytogenetic Location: 3q27

Molecular Location on chromosome 3: base pairs 184,371,935 to 184,379,688

(Homo sapiens Annotation Release 107, GRCh38.p2) (NCBI (

The THPO gene is located on the long (q) arm of chromosome 3 at position 27.

The THPO gene is located on the long (q) arm of chromosome 3 at position 27.

More precisely, the THPO gene is located from base pair 184,371,935 to base pair 184,379,688 on chromosome 3.

See How do geneticists indicate the location of a gene? ( in the Handbook.

Where can I find additional information about THPO?

You and your healthcare professional may find the following resources about THPO helpful.

You may also be interested in these resources, which are designed for genetics professionals and researchers.

What other names do people use for the THPO gene or gene products?

  • c-mpl ligand
  • megakaryocyte colony-stimulating factor
  • megakaryocyte growth and development factor
  • megakaryocyte stimulating factor
  • MGC163194
  • MGDF
  • ML
  • MPL ligand
  • myeloproliferative leukemia virus oncogene ligand
  • TPO

See How are genetic conditions and genes named? ( in the Handbook.

What glossary definitions help with understanding THPO?

blood clotting ; bone marrow ; cell ; clotting ; colony-stimulating factor ; familial ; gene ; hematopoietic ; inherited ; leukemia ; ligand ; nucleus ; oncogene ; platelets ; proliferation ; protein ; receptor ; stem cells ; thrombosis ; translation ; virus ; white blood cells

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.


  • de Graaf CA, Metcalf D. Thrombopoietin and hematopoietic stem cells. Cell Cycle. 2011 May 15;10(10):1582-9. Epub 2011 May 15. Review. (
  • Ghilardi N, Skoda RC. A single-base deletion in the thrombopoietin (TPO) gene causes familial essential thrombocythemia through a mechanism of more efficient translation of TPO mRNA. Blood. 1999 Aug 15;94(4):1480-2. (
  • Ghilardi N, Wiestner A, Skoda RC. Thrombopoietin production is inhibited by a translational mechanism. Blood. 1998 Dec 1;92(11):4023-30. (
  • Majka M, Ratajczak J, Villaire G, Kubiczek K, Marquez LA, Janowska-Wieczorek A, Ratajczak MZ. Thrombopoietin, but not cytokines binding to gp130 protein-coupled receptors, activates MAPKp42/44, AKT, and STAT proteins in normal human CD34+ cells, megakaryocytes, and platelets. Exp Hematol. 2002 Jul;30(7):751-60. (
  • NCBI Gene (
  • Wiestner A, Schlemper RJ, van der Maas AP, Skoda RC. An activating splice donor mutation in the thrombopoietin gene causes hereditary thrombocythaemia. Nat Genet. 1998 Jan;18(1):49-52. (


The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? ( in the Handbook.

Reviewed: September 2014
Published: February 1, 2016