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Homozygous β‐thalassaemia resulting in the β‐thalassaemia carrier state phenotype

1994; Wiley; Volume: 88; Issue: 3 Linguagem: Inglês

10.1111/j.1365-2141.1994.tb05074.x

1365-2141

Maria Cristina Rosatelli, Alessandra Pischedda, Alessandra Meloni, L. Saba, A Pomo, Maurizio Travi, Silvia Fattore, Antonio Cao,

Blood groups and transfusion

This paper describes the phenotypic manifestations of a very mild beta-thalassaemia mutation detected in several members of two families of Italian descent. The molecular defect, defined by denaturing gradient gel electrophoresis analysis and direct sequencing, consists of a C-->G substitution at position 844 of IVSII of the beta-globin gene within the consensus sequence of the IVSII acceptor splice site. Heterozygotes for this mutation show a haematological phenotype ranging in severity from silent beta-thalassaemia to that of a mild beta-thalassaemia carrier state, whereas homozygotes have the typical manifestations commonly resulting from heterozygosity for a beta-thalassaemia mutation. Compound heterozygotes for the IVSII nt844 (C-->G) mutation and a severe beta-thalassaemia mutation have the phenotype of thalassaemia intermedia. This paper indicates that the presence of borderline red blood cell indices or HbA2 values should make one suspect the presence of a very mild or silent beta-thalassaemia.