Hb San Diego [beta 109(G11)Val-->Met] in an Iranian: further evidence for a mutational hot spot at position 109 of the beta-globin gene

Secondary erythrocytosis due to hemoglobin San Diego

High-oxygen-affinity hemoglobin variants are a rare clinical entity that can present with secondary erythrocytosis. Herein, the author reports a case of a 41-year-old man with a 4-year history of secondary erythrocytosis of unknown etiology. Physical examination was unremarkable except for plethora of the palms. Myeloproliferative neoplasms and common causes of secondary erythrocytosis were ruled out. The P50 oxygen-hemoglobin dissociation curve was left shifted. Hemoglobin electrophoresis was silent; however, globin mass spectrometry revealed a β-globin variant. Globin sequencing confirmed hemoglobin San Diego. This case highlights the fact that rare high-oxygen-affinity variants should be considered in the differential diagnoses of secondary erythrocytosis.

Hemoglobinopathy Screening in a 15-Year-old Patient With Anemia

Identification of hemoglobinopathies in pediatric patients can be challenging and has important implications for the patient, as well as family members. Laboratory identification of uncommon hemoglobin (Hb) variants can pose a significant problem. Although many Hb variants can be largely identified using conventional electrophoresis and HPLC, confirmatory Hb DNA analysis may be necessary. This report provides an example of a pediatric patient with a complex heterozygous Hb by electrophoresis and HPLC, which necessitated identification by DNA analysis. Clinical and laboratory scenarios warranting Hb DNA analysis are additionally discussed.