JAK1 and Cognitive impairment: Instead, Phetrotinib is described as a highly specific JAK2 inhibitor, with a stronger inhibitory effect on JAK2 compared with JAK1, JAK3, and TYK2.[20,21] However, the safety profile of phetrotinib is still a subject of debate and ongoing research.[22] The patient’s neurological symptoms, such as dizziness, cognitive impairments, and blurred vision improved gradually after the treatment of phlebotomy, interferon, and low-dose aspirin antiplatelet therapy.