Print

JAK2

General aspects

Chronic Myeloproliferative Syndromes (CMS) are diseases of bone marrow caracterized from a abnormal proliferation of stem cells, causing a blood cell increase. Part of these family are Chronic Myeloid Leukemia (CML) with a Philadelphia chromosome (Ph) in the cells and CSM Ph negative such as Polycythemia Vera (PV), Essential Thrombocythemia (ET) and Idiopathic Myelofibrosis (IM). In thE Polycythemia Vera, the uncontrolled proliferation involves cells arising red cells; in the Essential Thrombocythemia cells arising proplatelet and in Idiopathic Myelofibrosis are involved proplates and leucocytes with connective tessue stack in the bone marrow. When the red cells e7o platelets come in the blood circulation in a strange quantity can cause dangerous complicances like venous and arterial thrombosis.


Genetic aspects

In the last few years, CSM Ph negative have achieved considerable advantaces throught the discovery of V617F mutation in Janus Kinase-2 (JAK2) gene. JAK2 gene encodes a protein, a tyrosin-kinase playng a foundamental role in the red cell progenitors, platelets and leucocytes proliferation. V617F mutation of Jak-2 gene consists in the substitution of valine with phenylalanine aminoacid causing a tyrosin-kinasic activity increase, so an uncontrolled proliferation of progenitor cells and a numerical increase of red cells, platelets, and leucocytes circulating. V617F mutation is shown in more then 90% of polycythemia cases, 40-50% of essential thrombocytemia and 50% of Idiopathic Myelofibrosis.


Genetic test

In Tecnobios Prenatale Eurogenlab is available a genetic test basade on Real Time Pcr technology to identify V617F mutation of JAK-2 gene; it is a qualitative test, that is it allows to define if a patient is or not a mutation carrier.


Genetic counseling

Our laboratory gives a genetic counseling service to inform patients and parents, in a clear terms about the genetic test results, features of disease, and treatments.

Response times

The DNA test results to identify V617F mutation of JaK-2 are available after 15 days from the draw blood.


Analyzed material

DNA extracted from peripheral blood lymphocytes collected in tubes with EDTA.

Sources sites
Tefferi A, Vardiman JW - Classification and diagnosis of myeloproliferative neoplasms: the 2008 World Health Organization criteria and point-of-care diagnostic algorithms. Leukemia. 2008

Tefferi A et al. - Proposals and rationale for revision of the World Health Organization diagnostic criteria for polycythemia vera, essential thrombocythemia, and primary myelofibrosis: recommendations from an ad hoc international expert panel. Blood. 2007.
 
Levine RL, Wadleigh M et al. Activating mutation in the tyrosine kinase JAK2 in polycythemia vera, essential thrombocythemia, and myeloid metaplasia with myelofibrosis. Cancer Cell. 2005