Haemoglobin GPhiladelphia and its interaction with haemoglobin S and alpha-thalassaemia in Nigerians

Abstract

Summary. The diagnosis of Hb SS/GPhiladelphia disease was made in four young Nigerians from separate families. Their Hb electrophoretic patterns on cellulose acetate membrane at alkaline pH were similar to those obtained in sickle‐cell haemoglobin C (HbSC) disease, but their clinical features and haematological data were consistent with the diagnosis of homozygous sickle‐cell disease. Family studies also revealed that they had inherited an additional a‐chain mutant haemoglobin. In one of the families, fingerprints of the globin peptides and amino acid analysis confirmed that the mutant haemoglobin was Hb GPhiladelphia (α2 68 Asn→Lys β2A). The results of the whole blood solubility test for sickle‐haemoglobin provided firm support for the diagnosis of homozygous sickle‐cell disease and distinguished clearly Hb SS/GPhiladelphia disease from Hb SC disease and Hb AS from Hb AGPhiladelphia heterozygotes. Restriction endonuclease mapping of the globin genes of the propositus and some relatives of one of the families revealed also that they were carriers of the α‐thalassaemia‐2 gene (deletion‐type). The globin gene‐analysis data indicate also that the αG Philadelphia and α‐thalassaemia genes are linked closely in Nigerians.

Homozygous hemoglobin S with concomitant hemoglobin G-Philadelphia: A diagnostic challenge

“…HbSS with Hb G‐Philadelphia was first reported in four Nigerians from separate families who were originally diagnosed with Hb SC disease. Family analysis with globin peptides and amino acid analysis ultimately demonstrated HbSS with Hb G‐Philadelphia . In our case, determination of the sister's genotype provided the clue to the patient's genotype.…”

Rare hemoglobins in Togo: A 15-year study at the Lomé University Campus Hospital Center

“…Mutant rare sans conséquence clinique ni hématologique, l'hémoglobine G Philadelphie a été décrite pour la première fois aux États-Unis chez un Noir [20]. Elle a été retrouvée en Afrique Occidentale (Nigeria) [21], puis en Italie [22] et à Taïwan [23].…”