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The Corfu δβ thalassaemia mutation in Greece: haematological phenotype and prevalence

1991; Wiley; Volume: 79; Issue: 2 Linguagem: Inglês

10.1111/j.1365-2141.1991.tb04537.x

1365-2141

Joanne Traeger‐Synodinos, Maria Tzetis, Emmanuel Kanavakis, A Metaxotou-Mavromati, Christos Kattamis,

Iron Metabolism and Disorders

Summary The Corfu δβ thalassaemia mutation, a 7.2 kb deletion partially removing the (δ‐globin gene and a single nucleotide mutation (GA) at intervening sequence I (IVSI‐n5) in the β‐globin gene in cis, was first described in a family from Corfu; the carriers for this mutation had the unusual haematological phenotype of heterozygous β‐thalassaemia with normal levels of HbA 2 . To investigate the frequency and haematological characteristics of Corfu δβ thalassaemia in Greece we analysed 25 unrelated normal HbA 2 type 2 β‐thalassaemia heterozygotes and their 23 clinically affected offspring. Gene mapping demonstrated that nine (36%) of the 25 normal HbA 2 β‐thalassaemia heterozygotes were in fact Corfu δβ thalassaemia heterozygotes and of the 23 patients, two were Corfu δβ thalassaemia homozygotes and five compound heterozygotes for Corfu δβ thalassaemia and another β‐thalassaemia defect. Detailed haematological analysis demonstrated that: the Corfu δβ thalassaemia mutation does not completely abolish the expression of the β‐globin gene; the HbA 2 levels are slightly lower (P<0.01) and the HbF levels slightly higher (P<0.01) in Corfu δβ thalassaemia heterozygotes compared to β‐thalassaemia heterozygotes with the normal HbA 2 ‐type 2 phenotype who do not have the Corfu δβ chromosome.