There were 14 heterozygotes and two homozygotes for alpha(+)-thalassemia; the remaining test subject carried a deletion of both alpha-globin genes (alpha(0) -thalassemia of the Southeast Asian type) on one chromosome 16, and triple alpha-globin genes on the other.
Nondeletional hemoglobin (Hb) H disease is caused by a deletion of both alpha-globin genes on one chromosome 16 and of an alpha(+)-thalassemia point mutation on the other chromosome 16.
The detection of beta-globin gene point mutation, as used here, is a highly specific and sensitive marker for engraftment and MC in patients with thalassemia.
Autonomous gene silencing and gene competition by globin promoters for locus control region (LCR) function have been proposed as mechanisms in developmental regulation of beta-like genes. deltabeta degrees thalassemias are syndromes presenting an increased production of fetal hemoglobin in adult life; the majority of them are due to various deletions in beta-globin gene cluster.
The transcription factor erythroid Kruppel-like factor (EKLF) specifically activates the beta-globin gene by interacting with the proximal beta-globin CACCC box, a known hot spot for thalassaemia mutations.
Heterogeneity in thalassemia is due to various modifying factors viz. coinheritance of α-gene defects, abnormal hemoglobin, XmnI polymorphism, variation in repeat sequences present in LCR, and silencer region of the gene.
We report the production and characterization of a transgenic mouse line (TG-β-IVSI-6) carrying the IVSI-6 thalassemia point mutation within the human β-globin gene.
This mutation was assumed to generate a truncated β-globin chain terminating at codon 60 with possible unstable variant leading to a 'null' or β<sup>0</sup>-thalassemia.
In the 106 samples with Hb A<sub>2</sub> 3.1-3.9%, six had HBB mutations; four Hb Dhonburi [codon 126 (T > G)], one CAP site mutation [CAP + 1 (A > C)] and one beta<sup>0</sup>-thalassemia [codon 41/42 (-TTCT)] with a coinherited HBD mutation [nt-77 (T > C)].
These signs correspond to her marked hypochromic, microcytic anemia with erythroid hyperplasia of the bone marrow. beta-Globin genotyping shows here to be compound heterozygous for the codon 39 C-->T beta zero-nonsense mutation and for the T-->C beta(+)-mutation at position 6 of the splice consensus at the exon 1/intron 1 junction (CD39 C-->T/IVS1-6 T-->C). alpha-Globin gene mapping demonstrates the presence of a 3.7-kb alpha (+)-thalassemia deletion on one allele (-alpha 3.7/alpha alpha).
Nondeletional hemoglobin (Hb) H disease is caused by a deletion of both alpha-globin genes on one chromosome 16 and of an alpha(+)-thalassemia point mutation on the other chromosome 16.
Correlation of haematological data and the location of deletions in two cases of HPFH and one case of deltabeta-thalassaemia suggest that a region of DNA located near the 5'-end of the delta-globin gene may be involved in the suppression in cis of gamma-globin gene expression in adults.
The diversity is far more important for the preponderant thalassaemia mutations of the Mediterranean area and is higher in the 5' part of the beta-globin gene.
We have tested this hypothesis for an element that covers the minimal distance between the thalassemia and HPFH deletions and is thought to be responsible for the difference between a deletion HPFH and deltabeta-thalassemia, located 5' of the delta-globin gene.
324 alleles of the beta-globin gene from unrelated thalassaemia patients native to the eastern region of India (mainly from the state of West Bengal) were analysed for beta-globin gene mutations by the amplification refractory mutation system (ARMS).
However, IC type parasites were most common among patients with homozygous alpha(+)-thalassaemia (93%), less frequent in heterozygotes (89%), and least frequent in alpha-globin normal children (84%, P(chi2 trend) = 0.03).
In this preliminary analysis of 587 bp of the HBB gene in selected thalassemic individuals, some rare mutations in world perspective have been found to be significantly high in the Bangladeshi population, together with the common mutations for thalassemia.
Discovering how the alpha and beta globin genes are normally regulated and documenting the effects of inherited mutations which cause thalassemia have played a major role in establishing our current understanding of how genes are switched on or off in hematopoietic cells.