RESUMO
<p><b>OBJECTIVE</b>To analyze the mutation rate and clinical characteristics of CALR, MPL W515K and JAK2 V617F genes in patients with primary thrombocythemia (PT).</p><p><b>METHODS</b>Fifty-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.</p><p><b>RESULTS</b>Among 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).</p><p><b>CONCLUSION</b>The 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.</p>