1/14. Hemoglobin Riyadh--alpha2beta2 (120(GH3)Lys replaced by Asn). A new variant found in association with alpha-thalassemia and iron deficiency.On a field trip toSaudi arabia (M.A.F.E.H.) in which the relationship between alpha-thalassemia and iron deficiency was studied, a fast moving hemoglobin variant was noted in a 30 year old Saudi Arabian woman. Analysis of the hemoglobin variant showed that the amino acid substitution was beta120 Lys replaced by Asn. This variant had not been described previously and has been named Hb Riyadh. There was also present an alpha-thalassemia and details are given of the imbalance of globin chain synthesis. It was possible to improve considerably the balance in vitro by the addition of hemin.- - - - - - - - - - ranking = 1keywords = thalassemia (Clic here for more details about this article) |
2/14. Differential diagnosis of Hb EE and Hb E-beta(0)-thalassemia by protein and dna analyses.dna analysis was used to confirm the Hb EE genotype and to differentiate from the possible genotype of Hb E-beta(0)-thalassemia in two Malay patients. The first patient was a 13-year-old Malay girl, whose parents were available for family studies. The second patient was a 69-year-old Malay woman with no living family members. The presence of Hb E in both propositi was confirmed by: (1) its characteristic electrophoretic mobilities on alkaline/acid gels; (2) its chromatographic properties on anion/cation exchangers, and (3) its mildly insoluble properties. However, differential diagnosis of Hb EE and Hb E-beta(0)-thalassemia was challenging in these two cases. In the former, this was because of the possible interactions of the parents' phenotypes; i.e., the mother had a similar phenotype. In the latter, it was due to the lack of any living family members for family studies. In this communication, we present the protein and dna analyses, including data on the use of the restriction enzyme Mnl I, for the definitive diagnosis of the Hb EE genotype in the propositi of these two Malay families.- - - - - - - - - - ranking = 1keywords = thalassemia (Clic here for more details about this article) |
3/14. diagnosis of concurrent hemoglobin h disease and heterozygous beta-thalassemia.Definitive diagnosis of concurrent hemoglobin (Hb) H disease and heterozygous beta-thalassemia cannot be made from Hb analysis alone, but necessitates genotype analysis and family study. Interactions between alpha- and beta-thalassemia must be considered when investigating moderate to severe hypochromic microcytic anemia of uncertain cause in adult patients from areas with a high prevalence of globin gene mutations.- - - - - - - - - - ranking = 1keywords = thalassemia (Clic here for more details about this article) |
4/14. Hb Suan-Dok [alpha109(G16)Leu-->Arg; CTG-->CGG (alpha2)] described in a patient of African ancestry.A 58-year-old Black female from Curacao (west indies) was recently referred to our Laboratory for a persistent microcytic hypochromic anemia. An analysis 13 years earlier had shown no abnormal hemoglobin (Hb) fractions and a balanced beta/alpha synthetic ratio. The hematological indices were again compatible with thalassemia and no abnormal fractions were observed on electrophoresis or high-performance liquid chromatography (HPLC). None of the seven common alpha-thalassemia (thal) deletion defects were present. Direct sequencing of the alpha2 gene revealed a CTG-->CGG single base substitution at codon 109. This mutation was previously described in a Thai patient (Hb Suan-Dok), inducing Hb H disease in association with a - -(SEA) allele. In contrast with earlier reports we were unable to identify any native Hb fraction. The balanced beta/alpha ratio indicated that alpha2-Suan-Dok is formed but does not form tetramer formation unless alpha-thal is present.- - - - - - - - - - ranking = 0.33333333333333keywords = thalassemia (Clic here for more details about this article) |
5/14. A novel alpha-thalassemia nonsense mutation in codon 23 of the alpha2-globin gene (GAG-->TAG) in a Tunisian family.Herein we describe a novel alpha-thalassemia (thal) point mutation in the alpha2-globin gene, found in a 3-year-old Tunisian girl who had Hb Bart's (gamma4) at birth, later on presenting with moderate anemia, microcytosis and hypochromia. She had a normal Hb A2 level and no abnormal hemoglobin (Hb) fraction. After excluding most of the common Mediterranean mutations, the alpha2-globin gene was sequenced and found to have a point mutation in the heterozygous state that creates a premature stop signal for translation (GAG-->TAG or Glu-->Term) at codon 23. The same mutation was also found in the mother in the heterozygous state, while the father had a normal sequence. The presence of the mutation was also confirmed by nucleotide sequencing of the opposite strand. Since the mutation creates a restriction site for the BfaI enzyme, a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP)-based assay was established for screening purposes.- - - - - - - - - - ranking = 0.83333333333333keywords = thalassemia (Clic here for more details about this article) |
6/14. An alpha-thalassemia phenotype in a Dutch Hindustani, caused by a new point mutation that creates an alternative splice donor site in the first exon of the alpha2-globin gene.The proband is an elderly woman (79 years of age) of Surinamese-Hindustani origin, suspected of being a carrier of a nondeletional alpha-thalassemia (thal) because of a moderate microcytic hypochromic anemia at normal ferritin levels and in the absence of any other alpha-thal deletions. sequence analysis revealed a silent mutation (GGC-->GGT) at codon 22 of the alpha2-globin gene. This mutation generates a splice donor site consensus sequence (GGTGAG) between codons 22 and 23. The abnormally spliced mRNA leads to a premature termination between codons 48 and 49. The presence of a downstream intron may induce the intracellular degradation of the affected mRNA, a pathway known as nonsense mediated decay (NMD), and this explains the alpha( )-thal phenotype observed in the patient. The codon 22 (GGC-->GGT) transition described in this report is the first mutation creating a splice donor site in one of the alpha-globin genes.- - - - - - - - - - ranking = 0.83333333333333keywords = thalassemia (Clic here for more details about this article) |
7/14. Hb Oegstgeest [alpha104(G11)Cys-->Ser (alpha1)]. A new hemoglobin variant associated with a mild alpha-thalassemia phenotype.A microcytic hypochromic anemic state was observed in an 8-year old Black female of Surinam origin during pre-operative Hb S [beta6(A3)Glu-->Val] screening. Her high zinc protoporphyrin (ZPP) level suggested a chronic iron depletion but, in contrast, the high red blood cell (RBC) count (5.85 x 10(12)/L) was indicative of a possible coexisting thalassemia. No abnormal hemoglobin (Hb) bands were present on high performance liquid chromatography (HPLC) or alkaline electrophoresis and the Hb A2 level was normal. Break point polymerase chain reaction (PCR) failed to reveal any of the common alpha-thalassemia (thal) mutations but selective dna sequencing of both alpha-globin genes disclosed a TGC-->AGC transversion at codon 104 of the alpha1 gene. cystine at codon 104 is involved in alpha/beta globin contact and has been described to be a critical amino acid of the alpha2 chain when substituted by a tyrosine (Hb Sallanches), inducing Hb H (beta4) disease in the homozygous state. Our heterozygous patient had a moderate anemia of 12.2 g/dL and a borderline haptoglobin suggesting some degree of hemolysis.- - - - - - - - - - ranking = 1keywords = thalassemia (Clic here for more details about this article) |
8/14. The first case of Hb E-Saskatoon associated with Hb Lepore-baltimore found in spain.Hb E-Saskatoon [beta22(B4)Glu-->Lys] does not cause any clinical symptoms in the heterozygous state. The homozygous state shows moderate phenotype expression. It has also been detected in association with beta-thalassemia. We present the first case of Hb E-Saskatoon associated with Hb Lepore-baltimore. This unusual combination of mutations does not aggravate the clinical picture, as only microcytosis and hypochromia have been observed. Hb E-Saskatoon can only be correctly characterized by ion exchange high performance liquid chromatography (HPLC) or by dna sequencing.- - - - - - - - - - ranking = 0.16666666666667keywords = thalassemia (Clic here for more details about this article) |
9/14. Investigation of persistent hypochromic microcytosis unmasks hemoglobin Evanston [alpha 14 (A12) Try--> Arg] in a patient of cyclic thrombocytopenia preceding Takayasu's disease.We report an unusual north Indian patient with Hemoglobin Evanston [alpha 14 (A12) Try --> Arg] who had acquired cyclic thrombocytopenia (10-1230 x 10(9)/l periodic oscillation of four week duration) which recovered without any specific therapy. She later developed Takayasu's disease and underwent three corrective stents. She is presently in clinical remission and is on regular follow up. To the best of our knowledge our patient is the first report of Hb Evanston from the indigenous population of india and highlights the need to look for point mutations in the alpha globin gene, which may interact with thalassemia or other hemoglobinopathies, in atypical cases. The association of these three disorders in our patient is possibly unrelated though an immune basis for the cyclic thrombocytopenia and Takayasu's disease is likely as seen in this report.- - - - - - - - - - ranking = 0.16666666666667keywords = thalassemia (Clic here for more details about this article) |
10/14. Hb Amsterdam [alpha32(B13)Met--Ile (alpha2)]: a new unstable variant associated with an alpha-thalassemia phenotype and a new African polymorphism.We have characterized a new abnormal hemoglobin (Hb) at position 32 of the alpha-globin chain. The proband, a 38-year-old woman of Surinamese Black ancestry, was referred to the Academic Hospital in Amsterdam, The netherlands, after 3 years of prednisone treatment in Surinam. kidney failure was diagnosed at the nephrology Department, Free University Medical Center, Amsterdam, The netherlands; the cortisone treatment was interrupted and dialysis was started. At this stage, a microcytic hypochromic anemia was observed with high reticulocyte (40%) and ferritin (500 microg/L) levels, and hemoglobinopathy was suspected. No abnormal bands were visible on alkaline electrophoresis and high performance liquid chromatography (HPLC). The Hb A2 level was normal (2.7%) and the erythrocyte count was low (3.59 x 10(12)/L) with a normal haptoglobin level (68 mg/100 mL). None of the common alpha-thalassemia (thal) deletion defects were present. The beta-globin gene sequence was normal but the alpha2-globin gene sequence revealed an ATG-->ATA transition at codon 32, changing the methionine into an isoleucine residue. The mutation, called Hb Amsterdam, was observed in the mother of the proband, who was also heterozygous for the--alpha3.7-thal deletion and affected by a moderate microcytic hypochromic anemia. Both Hb Amsterdam and the--alpha(-3.7) allele were found in association with a new polymorphism, IVS-I-39 (C-->T), previously observed in our laboratory in seven patients of African origin, on both the alpha1 and alpha2 genes. In addition, Hb Amsterdam was also associated with the common African alpha2 polymorphism (G-->CTCGGCCC at position 7238 and T-->G at position 7174). Hb Amsterdam is the first mutation ever described at codon alpha32, a position involved in alpha1/beta1 interaction. The possibility of a contribution of this mutation to the nephropatic state of the proband is discussed.- - - - - - - - - - ranking = 0.83333333333333keywords = thalassemia (Clic here for more details about this article) |
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