Hb Evans or α262 (E11) Val→ Metβ2 ; an unstable hemoglobin causing a mild hemolytic anemia

Abstract

Structural analysis of the α chain of the hemoglobin from a Caucasian female with a mild hemolytic anemia showed the presence of a variant with a Val→Met substitution at position α62. The valine at this position forms one of the contacts with heme and its replacement by methionine will likely decrease heme binding and cause a distortion of the heme crevice and a decreased stability of the abnormal protein. Dot-blot analysis of amplified DNA with 32P-labeled synthetic oligonucleotide probes confirmed the suspected G→A mutation in the first position of codon 62, and also located the mutation in the α2-globin gene. The mutation was found in the proposita and one of her daughters but was most probably absent in her parents.