[Clinical, structural and functional studies of HbG Philadelphia detected in a Moroccan newborn].

Abstract

Hb G Philadelphia (alpha68 Asn leads to Lys) is widely distributed in black people but is uncommon in North-Africa. Only one case has been previously described in an Arab immigrant. The latter and our propositus originated from North-East morocco. Hb G alpha Philadelphia is stable. The abnormal hemoglobin represented 28% of total hemoglobin in the hemolysate of the propositus, a 7 month old child. At birth, 4 fractions were detected on electrophoresis: Hb A, Hb F, Hb G Philadelphia, which migrated like Hb S, and a mutant alpha2Ggamma2. The oxygen affinity of Hb G Philadelphia was slightly elevated. Cooperativity and Bohr effect were normal. The abnormal hemoglobin was also detected in the father of the propositus in the heterozygote state: its clinical and hematological data were normal. No evidence of thalassemia trait was found in the family. The percentage of abnormal hemoglobin obtained in the propositus and his father is in accordance with the presence of two loci for the alpha chain on the homologous chromosome.