title: Hb H disease resulting from the association of an α-thalassemia allele [-(α)] with an unstable α-globin variant [Hb Icaria]: First report on the occurrence in Brazil.
abstract: Hb H Disease is caused by the loss or inactivation of three of the four functional α-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 α(0) 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.
authors.affiliation: Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, SP Brazil.
authors.forename: Elza M
authors.initials: EM
authors.lastname: Kimura
authors.forename: Denise M
authors.initials: DM
authors.lastname: Oliveira
authors.forename: Kleber
authors.initials: K
authors.lastname: Fertrin
authors.forename: Valéria R
authors.initials: VR
authors.lastname: Pinheiro
authors.forename: Susan E D C
authors.initials: SE
authors.lastname: Jorge
authors.forename: Fernando F
authors.initials: FF
authors.lastname: Costa
authors.forename: Maria
authors.initials: M
authors.lastname: de Fátima Sonati