Three Novel Calreticulin Mutations in Two Turkish Patients

Calreticulin (CALR) mutations were first identified exclusively in JAK2-MPL-negative essential thrombocythemia (ET) and primary myelofibrosis (PMF) at a rate of 60%-88%, accounting for 1/4 to 1/3 of all patients with ET and PMF [1,2,3]. As of today, more than 55 different types of mutations have been reported. The two most common mutations accounting for 85% of mutated cases are either a 52-bp deletion (type 1; c.1099_1150del; L367fs*46; 44%- 53% of cases) or a 5-bp insertion (type 2; c.1154_1155insTTGTC; K385fs*47; 32%-42% of cases). The remaining 15% include various other infrequent mutations that are often unique or found in only a few patients [4,5].