Final answer:
Polycythemia vera, a disease causing excessive production of RBCs, is linked to a JAK2 gene mutation leading to an active protein that increases blood viscosity and cardiovascular risks.
Step-by-step explanation:
Polycythemia vera is a type of bone marrow disease characterized by the excessive production of red blood cells (RBCs). It is associated with a mutation in the JAK2 gene, which codes for a protein that is part of the signaling pathways responsible for cell growth. Specifically, the mutation causes the JAK2 protein to be constantly active, leading to the uncontrolled production of RBCs and increased blood viscosity. This mutation, known as JAK2 V617F, leads to the activation of JAK2 protein, which stimulates the production of erythrocytes. The abnormal increase in red blood cell production contributes to the development of polycythaemia vera.
The JAK2 mutation is found in about 95% of patients with polycythaemia vera and can serve as a diagnostic marker for this disease. This can result in elevated blood pressure, and it makes it more difficult for the heart to pump blood, posing a risk for severe cardiovascular complications. Polycythemia vera is more common in males and typically presents in patients over 60 years of age.