Final answer:
In patients with essential thrombocytosis without the JAK2 mutation, the next most commonly mutated gene is the CALR gene. These CALR mutations result in a specific variant of the CALR protein that leads to overproduction of platelets.
Step-by-step explanation:
In patients with essential thrombocytosis without the JAK2 mutation, the next most commonly mutated gene is the Calreticulin (CALR) gene. Mutations in the CALR gene have been found in approximately 25-35% of essential thrombocytosis cases without the JAK2 mutation.
These CALR mutations result in a specific variant of the CALR protein that leads to overproduction of platelets. The presence of CALR mutations can help differentiate essential thrombocytosis from other myeloproliferative neoplasms.
Learn more about CALR gene mutations in essential thrombocytosis