Whole blood samples from patients with various forms of alpha- and beta- thalassaemia were incubated with 14C-Leucine to determine the relative rates of production of the alpha and beta chains by their reticulocytes. The labelled globin chains were fractionated by CM-Cellulose Chromatography in 8M Urea and the incorporated activity determined. The relative rates of synthesis of alpha and beta chains in some cases of alpha and beta- thalassaemia were established and the chain synthetic ratios were compared with similar ratios in normal individuals. The results show that it is possible to identify from the relative rates of in-vitro synthesis of the alpha and beta chains, the presence of the common thalassaemia slates in particular beta-thal trait, beta-thal homozygotes, Hb H disease and alpha0-thal trait. The presence of transfused blood does not affect the result. This study indicates that an abnormal alpha/beta chain synthesis ratio is useful in defining alpha and beta-thalassaemia variants.
The aim of this study was to screen and identify the types of thalassemia among blood donors at the Hospital Universiti Sains Malaysia (HUSM). Thalassemia screening was performed by hemoglobin electrophoresis. A total number of 80 blood samples were obtained from donors at the Transfusion Medicine Unit, HUSM. The ethnic origins of the donors were Malays (n=73, 91.3%) and non-Malays (n=7, 8.75%). Males comprised 88.1% of the donors. Thalassemia was detected in 16.25% (n=13) of the blood donors. Of those with thalassemia, 46.2% (6/13) were anemic. Microcytosis and hypochromia were detected in 84.6% (n=l1) and 84.6% (n=l1) of these donors, respectively. The types of thalassemias detected were Hb E, 11.25% (n=9/80) and beta thalassemia trait, 5% (n=4/80). Among the thalassemias detected, the Hb E hemoglobinopathy was comprised of Hb E/ alpha-thalassemia (38.5%: n=5), Hb E /beta-thalassemia (23.1%: n=3), Hb E trait (7.6%: n=1) and beta-thalassemia (30.8%: n=4). In conclusion, screening for thalassemia trait should be included as part of a standard blood testing before blood donation. Further studies are required to look at the effects of donated thalassemic blood.
The clinical spectrum of HbH disease varies from a benign disorder to a severe anemia which is blood-transfusion dependent. Heterogeneity at the clinical level is now being understood in terms of the underlying molecular defects. In this study a mild phenotype found in a group of patients with HbH disease is associated with two types of alpha-thalassemia. These are: alpha+-thalassemia (-alpha 3.7/) and alpha 0-thalassemia (--SEA/). In contrast, a second group with more severe HbH disease has a non-deletional alpha-thalassemia defect instead of alpha+-thalassemia (genotype alpha alpha T/--SEA). In the majority of cases, the basis for non-deletional alpha-thalassemia is Hb Constant Spring.
Progress in the functional studies of human olfactory receptors has been largely hampered by the lack of a reliable experimental model system. Although transgenic approaches in mice could characterize the function of individual olfactory receptors, the presence of over 300 functional genes in the human genome becomes a daunting task. Thus, the characterization of individuals with a genetic susceptibility to altered olfaction coupled with the absence of particular olfactory receptor genes will allow phenotype/genotype correlations and vindicate the function of specific olfactory receptors with their cognate ligands. We characterized a 118 kb β-globin deletion and found that its 3' end breakpoint extends to the neighboring olfactory receptor region downstream of the β-globin gene cluster. This deletion encompasses six contiguous olfactory receptor genes (OR51V1, OR52Z1, OR51A1P, OR52A1, OR52A5, and OR52A4) all of which are expressed in the brain. Topology analysis of the encoded proteins from these olfactory receptor genes revealed that OR52Z1, OR52A1, OR52A5, and OR52A4 are predicted to be functional receptors as they display integral characteristics of G-proteins coupled receptors. Individuals homozygous for the 118 kb β-globin deletion are afflicted with β-thalassemia due to a homozygous deletion of the β-globin gene and have no alleles for the above mentioned olfactory receptors genes. This is the first example of a homozygous deletion of olfactory receptor genes in human. Although altered olfaction remains to be ascertained in these individuals, such a study can be carried out in β-thalassemia patients from Malaysia, Indonesia and the Philippines where this mutation is common. Furthermore, OR52A1 contains a γ-globin enhancer, which was previously shown to confer continuous expression of the fetal γ-globin genes. Thus, the hypothesis that β-thalassemia individuals, who are homozygous for the 118 kb deletion, may also have an exacerbation of their anemia due to the deletion of two copies of the γ-globin enhancer element is worthy of consideration.
This comparative cross-sectional study was conducted in the pediatric daycare unit, Hospital Universiti Sains Malaysia to determine the prevalence of craniofacial deformities (CFD) and the association between these deformities and different clinical presentations among thalassemia patients. Patients were classified as either craniofacial deformity positive (CFD+) or craniofacial deformity negative (CFD-) by two examiners based on the presence or absence of deformity of the cheeks, frontal and/or maxillary bones. Fifteen clinical parameters were compared between the groups. Nineteen out of 43 patients (44.2%; confidence interval, 30.2-58.2%) had craniofacial deformities (CFD+). Both groups were comparable among the clinical parameters studied. Patients in the CFD+ group did not start their blood transfusions significantly earlier than the CFD- group (p = 0.50) and had a nonsignificantly lower mean pretransfusion hemoglobin level than the CFD- group (p = 0.71). Patients receiving regular monthly blood transfusions had a nonsignificantly smaller percentage of CFD than those transfused less often (p = 0.495). CFD+ patients had a splenectomy at a nonsignificantly younger age than CFD- patients (p = 0.36). HbE/beta thalassemia patients were not significantly less likely to develop CFD than other varieties (p = 0.50) and males had a nonsignificantly higher percentage of CFD than females (p = 0.29). This study shows CFD in thalassemia patients are still prevalent but no significant associated factors were found; however, a nonsignificantly higher prevalence of CFD was observed in patients with signs of severe disease and less efficient treatment.