Two New Gγ Chain Variants: Hb F-Clamart [γ17(A14)Lys→Asn] and Hb F-Ouled Rabah [γ19(B1)Asn→Lys]

Two new fetal hemoglobin variants affecting the Gγ chain are reported. Hb F-Clamart was found during investigation of a French newborn who presented with a mild microcytemia. the second variant was found during neonatal screening for hemoglobinopathies of 30,000 babies from a population-at-risk living in the Paris region. It was named Hb F-Ouled Rabah because its structural modification and ethnic distribution is similar to that of Hb D-Ouled Rabah [Gγ19(B1)AsnLys]. Hb F-Ouled Rabah is clinically silent and occurs at a frequency of ca. 0.1% in newborns originating from Maghreb. Structural characterization of both variants was done by protein chemistry methods, including amino acids analysis and mass spectrometry.