Most individuals display Janus activated kinase 2 (JAK2) V617F variant, calreticulin (CALR), or myeloproliferative leukemia (MPL) mutations (60%, 20%, and 3%, respectively), while 10% to 20% of ET cases do not exhibit any of these mutations (triple‐negative).10 Here, CALR is linked to essential thrombocythemia.