We describe three cases with hemoglobin (Hb) Adana, a nondeletional alpha chain mutation, compounded with an alpha globin gene deletion resulting in thalassemia intermedia.
Any alterations in the proximal CACCC and TATA boxes lead to a moderate decrease in synthesis of the β-globin chain, which has been demonstrated in cases of thalassaemia intermedia that have presented in the second decade of life with a moderate clinical course.
Unexpected severe phenotype in the family members may result from coexistence of extra α-globin genes, which is an important factor in the causation of thalassemia intermedia and major in heterozygous β-thalassemia.
The authors describe a Chinese child of β-thalassemia heterozygote with the mutation IVS2-654 (C→T) (HBB:c.316-197C→T) presenting with severe thalassemia intermedia.
To characterize different common mechanisms involving in pathogenesis of moderate to severe β-thalassemia intermedia, we have studied four factors in 38 Iranian patients with thalassemia intermedia: β-globin gene mutation, deletion in α-globin genes, presence of XmnI polymprphism and RFLP haplotype at β-globin gene cluster.
The presence of alpha globin cluster duplication should be considered in patients heterozygote for beta-thalassemia with thalassemia intermedia phenotype and in the carriers of suspected silent beta thalassemia.
Two common underlying mechanisms include co-inheritance of alpha globin gene deletions in homozygous thalassemia intermedia and presence of XmnI polymorphism.
In thalassemia major or intermedia, reduction in the number of alpha globin genes can ameliorate the disease phenotype; conversely, excess alpha globin genes can convert beta thalassemia trait to a clinical picture of thalassemia intermedia.
We report the clinical and hematological data and the molecular analysis and discuss the occurrence of alpha-globin genes duplication defects in cases of beta-thalassemia heterozygotes with thalassemia intermedia phenotypes.
Patients with Hb Neapolis in heterozygosis showed a slight alteration in HbA2 levels while compounds showed typical characteristics of thalassemia intermedia ranging from a non transfusion-dependent form for five patients to a transfusion-dependent form for one adult patient.
A novel beta-delta globin gene fusion, anti-Lepore Hong Kong, leads to overexpression of delta globin chain and a mild thalassaemia intermedia phenotype when co-inherited with beta(0)-thalassaemia.
Codon 104(-G), a heterozygous frameshift mutation in exon 2 of HBB, resulted in a dominantly inherited beta0-phenotype with mild anemia in a German kindred, and thalassemia intermedia in the index patient.
We report here a new frameshift mutation in exon 3 of the beta-globin gene, a single nucleotide deletion (-C) in between codons 140/141 (GCC/CTG-->GCC/TG), found in an 8-year-old Argentinean girl with clinical picture of thalassemia intermedia.
Based on the molecular analysis of beta-thalassemia intermedia, beta-thalassemia homozygotes or compound heterozygotes combined with alpha-thalassemia, as well as the conjunctive abnormalities of beta-thalassemia heterozygote with triplicated haplotype of alpha-globin genes, were the most common cause of thalassemia intermedia in China.
In some cases, impairment of two alpha-globin genes by point mutations led to a thalassemia-intermedia-like picture which could be misdiagnosed as beta-thalassemia.
We examined DNA from 28 patients with thalassaemia intermedia resident in London and 28 matched patients with thalassaemia major, for 3 types of genetic modifying factors, namely; mild beta-thalassaemia mutations, the upstream XmnI G-gamma globin gene polymorphism, and alpha-globin gene deletions.
The three patients homozygous for the alpha-globin gene locus (anti 3.7 kb arrangement) had beta(0)-thalassaemia mutations and a diagnosis of thalassaemia intermedia, preserving haemoglobin levels around 7-8 g/dl.
Heterozygosity for this postulated mutation (father of the patients with thalassaemia intermedia) may result in the production of a beta-thalassaemia carrier state with normal HbA2 level.