A Newly Characterized Hemoglobin Variant with a High Oxygen Affinity, Hb Fuchu-II, Presenting with Acute Myocardial Infarction.

A 65-year-old Japanese man presented with acute myocardial infarction (AMI) and polycythemia. Biochemical studies of the patient's hemoglobin (Hb) and the sequencing of his globin genes revealed that the polycythemia was secondary to a high oxygen affinity Hb variant, Hb Fuchu-II. Hb variants with high oxygen affinity can be an additional thrombotic risk factor in older patients and/or those with other risk factors. The patient was diagnosed with hemoglobinopathy after the development of AMI and exemplifies the importance of recognizing such conditions and of taking appropriate prophylactic interventions.