Hematological characterization and family pedigree. The patient originates from Surinam, a country with mixed ethnicity on the northeast Atlantic coast of South America. (A) Red blood cell parameters at the time of diagnosis of the patient and her parents. HbH inclusions were manually counted from a blood smear prepared after staining whole blood in an equal volume of Brilliant Cresyl Blue (BCB). Glycolytic enzyme analysis of the patient’s blood indicated the red blood cell population was composed of young cells, although the reticulocyte count was not markedly raised (hexokinase, 5.8 [normal range, 0.8-1.5], pyruvate kinase, 27.3 [6.1-12.3 U/g Hb], reticulocyte count, 127 × 10⁹/L). *Reference values are for nondeletional HbH disease, which is more severe than the deletional form.¹⁵  (B) Peripheral blood smear, Giemsa stained, from the patient. which shows marked hypochromia and anisopoikilocytosis (indicated by arrowheads) consistent with a diagnosis of hematologically severe HbH disease. (C) Peripheral blood HbH smear, BCB stained, from the patient. Arrowheads indicate typical cells containing HbH inclusions. (D) Family pedigree of the patient with annotated genotypes. Micrographs were taken using an Olympus BX60 microscope with an oil immersion 100× lens and Infinity 3S Lumenera camera. Hct, hematocrit; MCV, mean corpuscular volume; MCH, mean cell hemoglobin.