OBJECTIVETo analyze the mutation rate and clinical characteristics of CALR, MPL W515K and JAK2 V617F genes in patients with primary thrombocythemia (PT).

METHODSFifty-six patients with PT were selected as the research objects in our hospital. The CALR and MPL W515K gene mutations were determined by genomic DNA-PCR direct sequencing of the PCR products, and the JAK2 V617F gene mutation was detected by allele specific PCR method.

RESULTSAmong the 56 patients with PT there were 14 cases of CALR gene mutation with the incidence rate of 25%, including 6 cases of type I, 5 cases of type II and 3 cases of type III. The sex, age, platelet(Plt) count, white blood cell (WBC) count and hemoglobin (Hb) level in the type I case of CALR gene mutation all were not significantly different from that in type II and III(all P>0.05); the WBC level in type III group significantly increased in comparison of type II group (P<0.05), while the sex, age, Hb and Plt levels showed no significant difference between the type III and type II groups (P>0.05). There were 3 cases of MPL W515K gene mutation with the incidence rate of 5.36%; 21 cases of JAK2 V617F gene mutation with the incidence rate of 37.50%. There were 13 cases of CALR gene mutation in negative patients with MPL W515K and JAK2 V617F (18 cases) with 72.22% incidence rate (13/18), and there was no cases of 1 or 2 gene mutations coexisted. The levels of Hb and WBC in peripheral blood of patients with CALR mutation were significantly lower than those of JAK2 V617F mutation (both P<0.05). In 56 cases, there were 3 cases of abnormal karyotype, with the incidence rate of 5.36%. The mutation rate of CALR gene in abnormal karyotypes (66.67%) was significantly higher than that of normal karyotypes (20.75%) (P<0.01).

CONCLUSIONThe incidence of JAK2 V617F gene mutation increases in the patients with primary thrombocythemia; CALR mutation rate is higher in the patients with negative MPL W515K and JAK2 V617F gene mutation, which may closely correlate with abnormal karyotype; the levels of peripheral Hb and WBC in PT the patients with CALR gene mutation are significantly lower than those in patients with JAK2 V617F mutation.