A Second Case of Hb Fontainebleau [α21(B2)Ala→Pro] in an Individual with Microcytosis

Abstract

The identification of a second case of Hb Fontainbleau [α21(B2)Ala→Pro] allowed us to re‐examine its association with microcytosis, explore the effects of the mutation on protein stability and define the mutation at a DNA level. Although slightly unstable, the variant was expressed at 28–29% of the total and was caused by a heterozygous mutation in the α2 gene. There was no evidence for concomitant α-thalassemia (α-thal); both α-globin gene deletion analysis and sequencing of the α-globin locus failed to detect any additional mutations that might explain the relatively high expression level.