Detection of the JAK2 Gene Mutation in Familial Myeloproliferative Disorders and Significance in Chinese Peoples

Myeloproliferative disorders (MPDs) constitute a group of hematopoietic malignancies. Most of the MPD patient are sporadic and there are seldom reports in familial MPD. Present studies indicated that the excessus activation of signal transduction pathway of protein tyrosine kinase is an important factor in the pathogenesy of MPD. At present, except the CML, the other kinds of Ph-negative MPD are still unclear for pathogenesis. A new acquired mutation-JAK2V617F on JAK2 gene has been discovered successively in most of PV and in part of ET and IMF patient by scholars. Studies also discover that JAK2V617F mutation exists not only in the sporadic MPD but also in the familial MPD. Now only a few of studies has focus on the familial MPD abroad, and no report about JAK2V617F mutation in familial MPD chinese poeple.

Methods:

1. We mainly collected peripheral blood sample from the family members including the two MPD patients, then we took a routine blood count test and flow cytometry analysis (including CD34, CD41, CD61, CD71, CD117, GPA.

2. Inspection of the BM smear and pathology of BM biopsy is taken when is necessary.

3. we collected all the nucleated cells from the peripheral blood sample and then the DNA from the nucleated cells were extracted. We design a specific primer which is specific for codon V617 of the JAK2 gene according to the reference, and then amplify the target gene by PCR and confirm the PCR product by the way of electrophoresis, we use the restriction enzyme to digest the PCR product after purification.

4. We detect another acquired functionality gene mutation (MPLW515L/K) to the ET and IMF patient who are JAK2V617F negative by the way of PCR and DNA sequencing.

5. we also evaluated the specific markers that had been found in familial ET such as TPO and c-mpl gene mutation by the way of DNA sequence analysis for all of the member in the family, especially the ET patient and his children.

6. An research to detect the EPOR gene mutation on the family members especially for the PV patient and his children was carried.

Results: In summary, we found that many of the members are abnormal in routine blood test besides the two MPD patient, and some of them surpass the normal level. Of the member whose PLT count is much higher than normal count was also found abnormal in cell surface antigen expression, and we diagnosis it as the third MPD(ET) patient in this family combining with the result of BM cell morphologyand pathology of BM biopsy. There were total three members carried the JAK2V617F mutation in this family, including the two MPD patient and the father whose WBC count is higher than normal but without any clinical manifestation. We also found that all members who carried the JAK2V617F mutation are male, and affected in two generation of the family. Another female member whose PLT count is obviously higher than normal with JAK2V617F negative was diagnosised as JAK2V617F negative ET. Other common markers of MPD such as MPLW515L/K in JAK2V617F negative ET and TPO, c-mpl gene mutation in familial ET and EPOR gene in familial erythrocytosis could not being found in this family.

Conclusion: According to the results of our study, we found that an hereditary susceptibility may exits in this family which make the members in the family easier to development into MPD, and it is necessary to take carry an regular blood routine test and other related inspection for the family member. Our study hold on an investigation and an research in a familial MPD member for reach a goal of better understanding about JAK2V617F mutation frequency and Other common markers of MPD(sporadic MPD but also familial MPD) such as MPLW515L/K, TPO, c-mp, EPOR in this family and the role of those mutation in the pathogenesy in familial MPD, we provide some theory basis to further expounding of the pathogenesis and treatment in Ph- MPD, specially in discovering, diagnosis and prevention for the disease at a early stage. No research about the JAK2V617F mutation in familial MPD at present in chinese people, Therefore, our research is in advanced in domestic study.