Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0038002 (splenomegaly)
 9,873 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Homozygosity or compound heterozygosity for beta(0)-thalassemia mutations most commonly results in a transfusion-dependent thalassemia major phenotype. In this report, we describe a 55-year-old male, from Guinea-Bissau, that had been asymptomatic and never transfused until being admitted to hospital with anemia, fever, splenomegaly, and asthenia. Following hospital admission, HIV-2 and Mycobacterium tuberculosis infections were diagnosed, and biochemical and molecular studies revealed homozygosity for beta(0)-thalassemia. At the molecular level, this is the first description of homozygosity for the beta(0)-Black 1,393-bp deletion. In this case, the complete absence of beta-globin gene expression seems to be compensated by an unusually high fetal globin gene expression (Hb F 96%). Beta-globin haplotyping results were compatible with the propositus being homozygous for the Black 2 haplotype and for the absence of the XmnI polymorphism at -158 of (G)gamma-globin gene (-/-). Co-inheritance of genetic factors usually associated with high Hb F levels was not detected. Otherwise, the propositus is a heterozygote for the alpha-globin gene 3.7-kb deletion that is a beneficial modulating factor but not sufficient to explain this extremely mild phenotype. This unusual genotype/phenotype association is discussed in terms of the mechanisms underlying hemoglobin switching during development.
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PMID:Asymptomatic homozygous deletional beta(0)-thalassemia in an African individual. 1211 69

Gene therapy, the replacement of normal human beta- or gamma-globin genes into the hematopoietic stem cells of patients with homozygous beta-thalassemia, is a promising therapy for the future. High-level lineage-specific stable globin expression in transduced cells reinfused into patients in an autologous transplantation setting could be curative, if successful. Previous studies have shown high-level donor chimerism in nonmyeloablated non-thalassemic hosts. We have now studied the conditions for stable long-term engraftment of normal cells into a thalassemia mouse model that lead to high-level donor chimerism and correction of the abnormal phenotype. Thalassemic female mice treated with 0 to 300 cGy whole-body irradiation received transplantations of donor cells harvested from wild-type males. Engraftment of male cells was quantitated by Y-chromosome polymerase chain reaction analysis of blood and marrow progenitors, and changes in hemoglobin levels, red cell morphology, and spleen size were measured at various times posttransplantation. High-level stable donor cell engraftment was achieved in mice given 200 cGy and receiving transplants of 2 x 10(7) or more donor cells. The anemia, abnormal peripheral blood smears, and splenomegaly improved in the thalassemic mice that had successful engraftment. These studies demonstrate that stable and successful levels of engraftment of normal cells can correct the thalassemic phenotype without fully myeloablating the host. This animal model should allow us to test the amount of cytoreduction required and the level of engraftment and beta-globin expression needed in autologous transplantation of beta-globin gene-transduced cells to correct the abnormal phenotype in thalassemic mice, and it may be relevant to human clinical trials, as well.
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PMID:Correction of phenotype in a thalassemia mouse model using a nonmyeloablative marrow transplantation regimen. 1223 71

In this report, we describe two Thai siblings presenting with mild hypochromic microcytic anaemia and splenomegaly since 2(1/2) years of age. However, both patients were otherwise well with normal weight and height development and did not require transfusion during the 6-year follow-up period. Haematological and haemoglobin analyses were consistent with the clinical diagnosis of Hb E/beta-thalassaemia disease. To provide proper genetic counselling for this family, a definitive diagnosis of beta-thalassaemia was achieved using molecular analysis. We identified a rare initiation codon mutation (ATG-->AGG) of the beta-globin gene in combination with the Hb E mutation (codon 26: GAG-->AAG). The initiation codon mutation has previously been reported in several East Asian populations but has never been found in Southeast Asia and in combination with Hb E before. The haplotype analysis revealed a common origin of this mutation in the Asian population (5': - + - + + - +: 3', type IV with framework 3 according to Orkin S, et al.). Although this rare mutation abolished the beta-globin expression and was considered as beta(0)-thalassaemia, the relatively mild phenotype in our patients may be attributed to a strong association between this mutation and the -158 (G)gamma (C-->T) polymorphism, an XmnI cleavage site (+), resulting in a high propensity of postnatal gamma-globin expression and ameliorating the clinical phenotypes.
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PMID:Common origin of a rare beta-globin initiation codon mutation (ATG-->AGG) in Asians. 1630 46