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Homozygous β‐thalassaemia resulting in the β‐thalassaemia carrier state phenotype
Author(s) -
Rosatelli Maria Cristina,
Pischedda Alessandra,
Meloni Alessandra,
Saba Luisella,
Pomo Anna,
Travi Maurizio,
Fattore Silvia,
Cao Antonio
Publication year - 1994
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1111/j.1365-2141.1994.tb05074.x
Subject(s) - heterozygote advantage , compound heterozygosity , mutation , phenotype , genetics , beta thalassemia , hemoglobinopathy , biology , beta (programming language) , loss of heterozygosity , beta thalassaemia , microbiology and biotechnology , gene , allele , hemolytic anemia , thalassemia , immunology , computer science , programming language
Summary. This paper describes the phenotypic manifestations of a very mild β‐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 β‐globin gene within the consensus sequence of IVSII acceptor splice site. Heterozygotes for this mutation show a haematological phenotype ranging in severity from silent β‐thalassaemia to that of a mild β‐thalassaemia carrier silent β‐thalassaemia to that of a mild β‐thalassaemia carrier state, whereas homozygotes have the typical manifestations commonly resulting from heterozygosity for a β‐thalassaemia mutation. Compound heterozygotes for the IVSII nt844 (C G) mutation and a severe β‐thalassaemia mutation have the phenotype of thalassaemia intermedia. This paper indicates that the presence of borderline red blood cell indices or HbA 2 values should make one suspect the presence of a very mild or silent β‐thalassaemia.