Hicham Esselmani
Biological Engineering Laboratory, Faculty of Sciences and Techniques, Sultan Moulay Slimane University, Beni Mellal, Morocco
Youssef Nadir
Biological Engineering Laboratory, Faculty of Sciences and Techniques, Sultan Moulay Slimane University, Beni Mellal, Morocco
José-Maria Moraleda Jimenez
Instituto Murciano de Investigación Biosanitaria (IMIB)-Pascual Parrilla, Universidad de Murcia, Murcia, Spain; Department of Hematology, Hospital Clínico Universitario Virgen de la Arrixaca, Murcia, Spain
Mustapha Najimi
Laboratory of Pediatric Hepatology and Cell Therapy, Institute of Experimental and Clinical Research, UCLouvain, Brussels, Belgium; Private University of Marrakech, Marrakech, Morocco
Mohamed Merzouki
Biological Engineering Laboratory, Faculty of Sciences and Techniques, Sultan Moulay Slimane University, Beni Mellal, Morocco
ABSTRACT
Hemoglobin S/O Arab is a rare compound heterozygous hemoglobinopathy usually linked to severe sickle cell disease. We present the laboratory characterisation of an asymptomatic 34-year-old Moroccan woman in whom Hb S/O Arab was accidentally identified during routine glycated hemoglobin testing conducted before Ramadan fasting. Initial chromatographic analysis revealed abnormal hemoglobin fractions without detectable Hb A. Subsequent hemoglobin characterisation by high-performance liquid chromatography and capillary electrophoresis demonstrated the presence of Hb S (46.8%) and an unidentified variant (41.5%), with Hb F accounting for 9.6%. Hematological evaluation showed mild anemia (hemoglobin 11.8 g/dL), macrocytosis (mean corpuscular volume 110 fL), and reticulocytosis, accompanied by biochemical markers consistent with compensated hemolysis. Molecular analysis by Sanger sequencing of the HBB gene confirmed the presence of NM_000518.5:c.20A>T (p.Glu7Val; Hb S) and NM_000518.5:c.364G>A (p.Glu121Lys; Hb O Arab). A comparative analysis with previously documented cases emphasised the unusually mild phenotype seen in this patient. This case highlights the significance of precise laboratory identification and clinico-biological correlation in rare hemoglobin variants. Elevated fetal hemoglobin levels and possible genetic or cellular modifiers may influence phenotypic variability and should be considered during diagnostic assessment. This report highlights the essential role of laboratory medicine in diagnosing and assessing the risks of rare hemoglobinopathies.
Keywords: Hemoglobin S/O Arab, Asymptomatic Phenotype, Hemoglobin Electrophoresis, High-Performance Liquid Chromatography.
