Hemoglobin suresnes combined with α0-thalassemia: Diagnostic challenges and insights from trio-based whole exome sequencing

Hemoglobin Suresnes (Hb Suresnes) is a rare hemoglobin variant caused by a substitution of arginine to histidine at position 141 (p.Arg142His) in the COOH terminus of the α-globin chain. This structural change alters the oxygen affinity of hemoglobin and leads to erythrocytosis. We report the first genetically confirmed case of Hb Suresnes co-inherited with α⁰-thalassemia (--/αα) in an East Asian patient, diagnosed via trio whole exome sequencing (WES). A 33-year-old male presented with asymptomatic erythrocytosis, microcytosis, and a family history of elevated red cell indices. Under genetic analysis with WES, we identified a heterozygous Hb Suresnes variant [NM_000558.3(HBA1): c.425G > A (p.Arg142His)] inherited from his father, alongside α⁰-thalassemia (--/αα) inherited from his mother. The overlapping hematologic phenotype initially mimicked polycythemia vera, prompting empirical therapeutic phlebotomy. This case highlights the diagnostic pitfall of misclassifying hereditary erythrocytosis as polycythemia vera and emphasizes the role of WES in resolving the complexity of coexisting hemoglobinopathies, ensuring accurate diagnosis and appropriate management.