Abstract
Background:Hemoglobin (Hb) Alesha is a rare and very unstable Hb variant, resulting in disruption of the heme pocket and producing severe hemolysis in heterozygous statues. In this study, we describe the first report of this variant in an Iranian boy originated from south of Iran with severe hemolytic anemia and mild splenomegaly. Methods:A six-year-old boy from Khuzestan Province and his parents were studied. Gap-PCR and direct sequencing were performed to detect the -globin gene deletions and β-globin gene mutations, respectively. Results:The subject had a sporadic mutation GTG to ATG (Val [valine]>Met [methionine]) at codon 67 in heterozygous form on β-globin gene, which was not detected in his parents. Conclusion:Since both parents proved to be normal, this Hb variant could be considered as a de novo mutation, which is highly useful for prenatal diagnosis.
Highlights
Most hemoglobin (Hb) variants result from single amino acid substitutions in α- or βglobin structures
Hb Alesha has not been detected by cellulose acetate electrophoresis at alkaline pH (8.4-8.6); so it is considered as an unstable Hb variant
The Hb Alesha or Hb Bristol is a rare and very unstable Hb molecule that most patients require frequent blood transfusions and splenectomy. This Hb variant had a wide variety of clinical manifestations, due to introduction of the larger Met residue into the heme pocket, and loss of the bonds between Val at β67 and the heme group[6]
Summary
Most hemoglobin (Hb) variants result from single amino acid substitutions in α- or βglobin structures. A complementary experiment using both protein and DNA sequencing of the British patient showed that the primary reported mutation of Hb Bristol known as βV67D that was performed by using protein study was not a correct one; the correct mutation of Hb Bristol was identical to Hb Alesha mutation (β 67[E11] Val to Met). This difference is due to a posttranslational mechanism in which the translated Met converts into an Asp residue[3].
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