Hb H disease resulting from the association of an αº-thalassemia allele [-(α)20.5] with an unstable α-globin variant [Hb Icaria]: first report on the occurrence in Brazil

• Autor(a) principal: Kimura,Elza M.
• Data de Publicação: 2009
• Outros Autores: Oliveira,Denise M., Fertrin,Kleber, Pinheiro,Valéria R., Jorge,Susan E.D.C., Costa,Fernando F., Sonati,Maria de Fátima
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Genetics and Molecular Biology
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572009000400007
• topic: hereditary hemoglobinopathies; alpha-thalassemia; Hb H disease; Hb Icaria

Hb H Disease is caused by the loss or inactivation of three of the four functional a-globin genes. Patients present chronic hemolytic anemia and splenomegaly. In some cases, occasional blood transfusions are required. Deletions are the main cause of this type of thalassemia (α-thalassemia). We describe here an unusual case of Hb H disease caused by the combination of a common αº deletion [-(α)20.5] with a rare point mutation (c.427T > A), thus resulting in an elongated and unstable α-globin variant, Hb Icaria, (X142K), with 31 additional amino-acid residues. Very high levels of Hb H and Hb Bart's were detected in the patient's red blood cells (14.7 and 19.0%, respectively). This is the first description of this infrequent association in the Brazilian population.