Hb J-Guantanamo: a Rare Hemoglobin Variant Identified in Morocco Following Unexpected HbA1c Results.

BACKGROUND: While hemoglobin variants are common worldwide, many remain undetected due to their silent clinical expression. Some, however, may compromise the reliability of diagnostic markers such as HbA1c. We report a rare β-globin variant, hemoglobin J-Guantanamo, identified in Morocco. METHODS: A hemoglobin variant was incidentally discovered in a 59-year-old patient during hemoglobin A1c measurement. Multiple phenotypic methods were employed for characterization, including capillary electrophoresis, high-performance liquid chromatography, and hemoglobin gel electrophoresis. RESULTS: Based on the concordance of phenotypic findings, the variant was identified as Hb J-Guantanamo. Although the patient remained asymptomatic with no hematologic abnormalities, the variant interfered with HbA1c measurement, highlighting its potential impact on diabetes monitoring. CONCLUSIONS: This case underscores the diagnostic challenges associated with rare hemoglobin variants, emphasizes the necessity of multiple analytical methods for accurate identification, and contributes to the limited data on hemoglobinopathies in Morocco.