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At least 19 recordsLinked to original sources
PubMed2001

Simultaneous PCR detection of beta - thalassemia and alpha - thalassemia 1 (SEA type) in prenatal diagnosis of complex thalassemia syndrome.

OBJECTIVE: To establish a rapid PCR method for simultaneous detection of beta-thalassemia and alpha-thalassemia 1 genes for diagnosis of complex alphabeta-thalassemia syndrome. DESIGN AND METHODS: Using multiplex allele specific PCR approach, we evaluated a simultaneous detection of the SEA type alpha-thalassemia 1 and the common Southeast Asian beta-thalassemia and hemoglobin E genes. The system was tested on known cases of double heterozygote for alpha- and beta-thalassemias and in a prenatal diagnosis of complex alphabeta-thalassemia syndrome. RESULTS: Co-inheritance of alpha-thalassemia 1 (SEA type) with each of the common beta-thalassemia genes in Southeast Asian and with hemoglobin E could be identified in a single PCR reaction. A successful application of this simultaneous detection system in prenatal diagnosis of a complex thalassemia syndrome caused by an EFBart's disease was demonstrated in a Thai family. CONCLUSION: We have shown that correct diagnosis of double heterozygosity for alpha-thalassemia 1 and beta-thalassemia or hemoglobin E could be obtained using a simultaneous multiplex PCR. These rapid PCR assays would facilitate characterization and prenatal diagnosis of complex thalassemia syndromes in the regions where both alpha- and beta-thalassemias and hemoglobin E are common.

Chorionic Villi Sampling↗
PubMed1999

Interaction of an alpha(+)-thalassemia deletion with either a highly unstable alpha-globin variant (alpha2, codon 59, GGC-->GAC) or a nondeletional alpha-thalassemia mutation (AATAAA-->AATAAG): comparison of phenotypes illustrating "dominant" alpha-thalassemia.

Thalassemia syndromes and unstable hemoglobins traditionally represent two phenotypically separate disorders of hemoglobin synthesis. Highly unstable hemoglobin variants, however, often have phenotypic characteristics associated with both ineffective erythropoiesis (thalassemias) and peripheral hemolysis (unstable hemoglobins). Many highly unstable beta chain variants cause a dominant thalassemia-like phenotype, in which simple heterozygotes for such mutations have a clinical expression similar to thalassemia intermedia. The phenotypic expression of highly unstable alpha-globin variants is usually less severe, due mainly to a gene dosage effect, and they are often only characterized on interaction with other alpha-thalassemia mutations, whence they are classified as nondeletional alpha-thalassemia determinants. This study reports the clinical and hematological findings in five cases with rare alpha-thalassemia genotypes: a single patient with the thalassemic alpha2-globin gene codon 59 Gly-->Asp hemoglobin variant in trans to an alpha(+)-thalassemia deletion, and four compound heterozygotes for the nondeletional alpha-thalassemia polyadenylation mutation (alpha2 gene AATAAA-->AATAAG or alpha(T-Saudi)alpha/-alpha) and an alpha(+)-thalassemia deletion. Evaluation of the clinical and hematological features in these two analogous genotypes clearly demonstrates the more severe clinical expression associated with the alpha-thalassemic unstable hemoglobin variant. In addition, the case in this study with the codon 59 alpha chain variant provides a further example illustrating the spectrum of phenotypes associated with the alpha-thalassemic hemoglobinopathies.

Adolescent↗
PubMed2004

Thalassemia intermedia due to co-inheritance of beta0/beta(+)-thalassemia and (- -SEA) alpha-thalassemia/Hb Westmead [alpha122(H5)His > Gln (alpha2)] in a Chinese family.

Two brothers from a Chinese family with beta-thalassemia intermedia who harbor both alpha- and beta-globin gene defects are described. They are both compound heterozygous for codons 41/42 (-CTTT) beta0-thalassemia and nt - 28 (A > G) beta(+)-thalassemia mutations together with concurrent (- -SEA) alpha-thalassemia (SEA) deletion. One sibling also harbors Hb Westmead, giving an unusual genotype of beta0/beta(+)-thalassemia and (- -SEA) alpha-thalassemia/Hb Westmead. With respect to the age at presentation and transfusion requirement, this subject shows a milder clinical phenotype than his brother, most probably explainable by the presence of Hb Westmead in addition to the SEA deletion, which causes a further amelioration of the alpha-chain excess and hence a less severe disease. For areas with high prevalence of both alpha- and beta-thalassemia mutations, their interactions should always be considered in genotype phenotype correlation. Moreover, routine laboratory diagnostic strategy for non-deletional alpha-globin gene mutations in the Chinese may need to include Hb Westmead, as it is a common alpha-globin gene mutation in our population apart from Hb Constant Spring and Hb Quong Sze.

Adult↗
PubMedDate not supplied

Effect of alpha-gene numbers on the expression of beta-thalassemia intermedia, beta-thalassemia and (delta beta)0-thalassemia traits.

The effects of variations in alpha-gene numbers on phenotypical expression of beta-thalassemia are assessed in 11 subjects of 8 families. The study indicates that coexistence of alpha-thalassemia (-alpha3.7/alpha alpha) decreases the HbF in IVSI-6 homozygote and in delta beta thalassemia trait and may ameliorate the disease in beta-thalassemia compound heterozygotes associated with one mild and one severe beta-thalassemia mutation. Coexistence of alpha-gene triplication is associated with an increase in HbF value and may increase the severity of beta-trait or beta-thalassemia intermedia. The effects of alpha-gene triplication on phenotypic expression of beta-thalassemia trait may not be uniformly observed in every subject affected with a similar genotype.

Adolescent↗
PubMed1993

Thalassemia intermedia: compound heterozygous beta zero/beta(+)-thalassemia and co-inherited heterozygous alpha(+)-thalassemia.

The relative excess of alpha- over beta-globin chains in the erythroid precursors is the chief pathophysiological factor of homozygous beta-thalassemia. The clinical picture is usually characterized by a transfusion-dependent dyserythropoietic anemia (thalassemia major). However, some patients present with moderate anemia that does not require regular blood transfusions (thalassemia intermedia). The molecular heterogeneity of beta-thalassemia mutations and changes of alpha- and gamma-globin gene expression play an important role in modifying the clinical phenotype. We report here on a female Greek patient with homozygous beta-thalassemia but normal growth and development, excellent exercise tolerance, and no need of blood transfusions. She is thus mildly affected clinically, although there is marked pallor, jaundice, and hepatosplenomegaly. 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). Taken together, this study identifies a complex interaction of genetic factors that do not significantly alter the clinical phenotype when present alone but ameliorate the course of homozygous beta-thalassemia when inherited in combination.

Base Sequence↗
PubMed2005

Thalassemia heart disease: a comparative evaluation of thalassemia major and thalassemia intermedia.

BACKGROUND: Heart disease represents the main determinant of survival in beta-thalassemia, but its particular features in the two clinical forms of the disease, thalassemia major (TM) and thalassemia intermedia (TI), are not completely clarified. METHODS: We compared clinical and echocardiographic global parameters in 131 TM patients who received regular chelation transfusions and were highly compliant with treatment (mean age, 28 +/- 6 years [+/- SD]), and 74 age-matched, TI patients who did not receive chelation transfusions. RESULTS: Congestive heart failure was encountered in five patients with TM (3.8%; age range, 25 to 29 years) and in two patients with TI (2.7%; age range, 37 to 40 years). Systolic left ventricular (LV) dysfunction (ejection fraction < 55% or shortening fraction < 35%) was only encountered in patients with TM (8.4%). Considerable pulmonary hypertension (systolic tricuspid gradient > 35 mm Hg) was only present in TI (23.0%). In the remaining patients without evident heart disease, cardiac dimensions, LV mass, LV shortening and ejection fractions, and cardiac output were significantly higher in patients with TI. LV afterload was higher in patients with TM. LV diastolic early transmitral diastolic peak flow velocity (E)/late transmitral diastolic peak flow velocity (A) ratio was also higher in TM. Systolic and mean pulmonary artery pressures and total pulmonary resistance were higher in both young and old TI patients. CONCLUSION: Regular lifelong transfusion and chelation therapy in TM prevented premature heart disease and pulmonary hypertension, although LV dysfunction still occurred and led to heart failure. The absence of regular therapy in TI, in contrast, preserved systolic LV function but allowed pulmonary hypertension development, which also led to heart failure, starting within the fourth decade of life, a decade later compared to TM.

Adult↗
PubMed1997

Red cell parameters in alpha-thalassemia with and without beta-thalassemia trait or hemoglobin E trait.

Eighty-five patients who attended at Ramathibodi Hospital during November 1994 to June 1996 were investigated for thalassemia genotype, hemoglobin (Hb) typing and blood cell parameters. All patients were screened primarily for complete blood count using the Technicon H*3 automated hematology analyzer and Hb typing using the automated HPLC. Their genotypes were evaluated by in vitro gene amplification using primers for detection of common alpha-thalassemic genes found in the Thai population. We found 45 cases out of 85 were alpha-thalassemia trait with A2A typing, 10 were normal, 7 were alpha-thalassemia trait complicated by beta-thalassemia trait or HbE trait, 18 were HbH disease or HbH with Hb Constant Spring (HbH/CS), and 5 were AE Bart's disease. The alpha-thalassemia 1 trait had heterogeneity in red cell population as shown by increased red cell distribution width (RDW), the increased percent microcytic red cell (%Micro) and decreased mean cell volume (MCV). Red cell parameters in alpha-thalassemia 2 trait and HbCS trait were not significantly different from normal. The cases with coinheritance of alpha-thalassemia trait with beta-thalassemia trait or with HbE trait showed variation in their red cell parameters: one case showed less abnormal red cell parameters than those of uncomplicated alpha-thalassemia but the other two cases showed unimproved values. The homozygous alpha-thalassemia 2 showed similar red cell parameters to the alpha-thalassemia 1 trait. In conclusion, we can screen the alpha-thalassemia 1 trait and homozygous alpha-thalassemia 2 by using the simple red cell parameters such as the MCV and RDW; however, they must be confirmed for alpha-thalassemic genes. Unfortunately, red cell parameters of alpha-thalassemia 2 trait or HbCS trait were not different from those of normal subjects.

Erythrocytes↗
PubMed1999

MR imaging of the brain: findings in asymptomatic patients with thalassemia intermedia and sickle cell-thalassemia disease.

OBJECTIVE: The purpose of this study was to evaluate the spectrum of MR findings of the brain in asymptomatic patients affected with thalassemia intermedia or sickle cell-thalassemia disease to prevent brain damage by identifying patients at risk for stroke so that transfusional or pharmacologic treatment could be implemented. SUBJECTS AND METHODS: Forty-one asymptomatic patients who were younger than 50 years and were affected by minor hemoglobinopathies underwent MR imaging of the brain. Ischemic lesions were classified as small, medium, or large and as single or multifocal. Atrophic changes were graded subjectively as mild, moderate, or severe. A grade of brain damage was assigned to every patient. The frequency and severity of brain damage were correlated with the number of sickle-cell crises per year, hemoglobin level, sickling hemoglobin level, platelet count, sex, and age. RESULTS: Of the patients with thalassemia intermedia, 37.5% showed asymptomatic brain damage, and 52% of those with sickle cell-thalassemia disease showed asymptomatic brain damage. In the thalassemia intermedia group, atrophy was always mild and ischemic lesions were generally small (25%) and single (25%). Among the patients with sickle cell-thalassemia disease, 24% had small, 16% had medium, and 12% had large ischemic lesions. Multifocal lesions were twice as common in the patients with sickle cell-thalassemia disease (20%) as in those with thalassemia intermedia (12.5%). Only in the patients with thalassemia intermedia did the frequency of brain damage increase with age. Moreover, brain damage inversely correlated with hemoglobin level in patients with thalassemia intermedia but not in those with sickle cell-thalassemia disease. Brain damage was more severe in patients with sickle cell-thalassemia disease who had more crises per year. CONCLUSION: This study suggests that patients with thalassemia intermedia and those with sickle cell-thalassemia disease may have asymptomatic brain damage. Our results suggest that MR imaging is useful in identifying patients at risk for stroke so that they can be treated with transfusional or pharmacologic therapy.

Adolescent↗
PubMed1993

[Molecular-genetic characteristics of alpha, beta and delta beta-thalassemias in 139 heterozygotes in 56 unrelated Czech and Slovak families (Priority description of 3 beta-thalassemia mutations, an extensive alpha-thalassemia 2 (18+ kb) deletion and a Swiss-type nondeletion hereditary persistence of hemoglobin F)].

In 135 subjects from 54 unrelated families of Czech and Slovak families the authors identified 11 different beta-thalassaemic alleles. In 25 families they proved a IVS I-1 (G-A) mutation. Another 4 "mediterranean" mutations: IVS II-1 (G-A), IVS II-745 (C-G); IVS I-110 (G-A) and mutations in the codon 39 (C-T) were found in 18 families. Mutation IVS I-5 (G-C) found in one family is common in Asia. A frameshift at codons 82/83(-G) found in two families, was described previously only by Schwartz in one families from Azerbaijan. A rare mutation in codon 121 (C-T) is usually characterized as beta-thal. with formation of Heinz bodies. The latter were however found only in one of three families with this allele. Newly detected alleles include: mutation in codon 112 (T-A) found in one family (surprisingly also without formation of Heinz bodies); mutation in CD 115 (GCC-GAC) which results in unstable variant of Hb-Hradec Králové alpha 2 beta 2 115 (G17) Ala-Asp with formation of Heinz bodies and a frame shift in codons 38/39(-C) found in two families. In one of them there was also a new mutation of the promotor area of the G gamma gene (-110 A-C) causing the Swiss type of the disease with hereditary persistence F haemoglobin. The so-called Sicilian type of delta beta thalassaemia caused by deletion of DNA length cca 13 kb starting in IVS-II was found in one patient. alpha-thalassaemic mutations are rare in this population. In addition to common alpha-thalassaemia 2(-3,7 kb) deletion, however, also a new alpha-thalassaemia 2 was found caused by a large (18+kb) deletion involving alpha 1 and theta globin genes. alpha alpha alpha anti 3,7 triplication found in 7 beta-thal. heterozygotes led to deterioration of parameters of the red cell haemogram.

Base Sequence↗
PubMed2005

Sensitivity and specificity of mean corpuscular volume testing for screening for alpha-thalassemia-1 and beta-thalassemia traits.

AIM: To evaluate the sensitivity, specificity, positive predictive value and negative predictive value of mean corpuscular volume (MCV) testing for screening for both alpha-thalassemia-1 and beta-thalassemia traits. METHODS: A diagnostic test was conducted on 439 pregnant women attending the antenatal care (ANC) clinic at Maharaj Nakorn Chiang Mai Hospital between April 2002 and July 2002. Blood samples were collected from the pregnant women after they were counseled and gave informed consent. The MCV was measured in all samples using an automated hematology analyzer. The hemoglobin (HbA2) level and polymerase chain reaction (PCR) were measured in all cases to test for the beta-thalassemia trait and the alpha-thalassemia-1 gene (South-East Asian [SEA] type), respectively. The data were collected and analyzed for sensitivity, specificity, positive predictive value and negative predictive value for evaluating the efficacy of MCV testing for screening for both alpha-thalassemia-1 and beta-thalassemia traits. RESULTS: Positive MCV tests (</=80 fl) showed a sensitivity of 92.9% and specificity of 83.9% in screening for alpha-thalassemia-1 and beta-thalassemia traits, respectively. The positive predictive value and negative predictive value were 37.9% and 99.1%, respectively. CONCLUSION: MCV evaluation is a useful tool for screening for alpha-thalassemia-1 and beta-thalassemia traits during pregnancy because of its simplicity, low cost and high sensitivity.

Adult↗
PubMed2006

Molecular detection of Spanish deltabeta-thalassemia associated with beta-thalassemia identified during prenatal diagnosis.

BACKGROUND: beta-Thalassemia is one of the most common single gene disorders and is widely distributed in the Mediterranean region. The deltabeta-thalassemias are a rare group of disorders, however in Spain the Spanish deltabeta0 thalassemia that removes 114 kb of beta-globin cluster is quite frequent. METHODS: To establish a molecular diagnosis of beta-thalassemia in a second-trimester fetus from a couple who are beta-thalassemia carriers, a rapid real-time PCR method was performed to detect major mutations prevalent in people of the Mediterranean basin (IVS I-1, IVS I-6, IVS I-110, CD-6, CD-37, and CD-39). The Spanish deltabeta0 deletion was detected using PCR with deletion-specific primers. RESULTS: The father was diagnosed as a carrier for the IVSI-6 (T>C) mutation and the mother as carrier for the Spanish deltabeta0 deletion. The fetus was a compound heterozygote for both those mutations. The phenotype of compound heterozygosity for deltabeta/beta-thalassemia can range from mild thalassemia intermedia to thalassemia major. After confirming these results in the DNA from amniocentesis obtained at the 20th week of gestation, the couple decided to terminate the pregnancy. CONCLUSIONS: This paper reports the first molecular characterization of Spanishdeltabeta0-thalassemia associated with beta-thalassemia IVSI-6, and confirms the importance of prenatal genetic testing for single gene disorder such as beta-thalassemia.

Adult↗
PubMed1970

Mild thalassemia: the result of interactions of alpha and beta thalassemia genes.

Homozygous thalassemia is due to inherited unbalanced synthesis of the alpha- or beta-chains of hemoglobin. Clinical severity may be in part related to the extent of alpha:beta imbalance. Two families are presented that illustrate this concept. Thalassemia in these individuals was evaluated by clinical and genetic criteria. The relative rates of alpha- and beta-chain synthesis in their reticulocytes were estimated by the extent of incorporation of 1-leucine-U-(14)C into the chains. Unusual combinations of clinical and hematological data and biosynthetic ratios were obtained in certain individuals which indicated the presence of combinations of alpha- and beta-thalassemia genes. The propositus of the first family had mild Cooley's anemia and was believed to have one alpha- as well as two beta-thalassemia genes. Presumably the alpha-thalassemia gene interfered with alpha-chain production which lead to less accumulation of alpha-chains and a reduced rate of intramedullary and peripheral hemolysis. In the second family two individuals were believed to have an alpha-thalassemia, a "silent carrier," and a beta-thalassemia gene. Despite the fact that they appeared to have the genotype of hemoglobin H disease, their cells contained no hemoglobin H and had a normal lifespan presumably because excess beta-chain production was inhibited by the beta-thalessemia gene. These family studies suggest that the alpha:beta imbalance observed in thalassemia may be favorably influenced by combinations of alpha- and beta-thalassemia genes.

Adult↗
PubMed1991

Molecular characterization of beta-thalassemia intermedia in patients of Italian descent and identification of three novel beta-thalassemia mutations.

In this study, we have defined by dot-blot analysis with allelic specific oligonucleotide probes or direct sequencing on amplified DNA the beta-thalassemia mutations in a large group of patients (23) of Italian descent with thalassemia intermedia. These patients had one parent with either the silent beta-thalassemia carrier phenotype or borderline-normal hemoglobin A2 (HbA2) levels (2.5% to 3.5%). Nearly all were genetic compounds for a severe beta-thalassemia mutation and a beta-thalassemia mutation associated with high residual output of beta-globin chains (beta + intervening sequence [IVS]-I-nt6, beta -87, beta -101), indicating that inheritance of a mild beta-thalassemia allele, even in a single dose, is the most common molecular mechanism producing thalassemia intermedia in the Italian population. In three cases, in whom we failed to define by dot-blot analysis the mutations, we sequenced the beta + globin gene and found three novel beta-thalassemia mutations, which are certainly very rare because they have been hitherto detected solely in a single patient. These mutations consist of: (1) a T-A substitution at position 2 of IVS-I, in a patient compound heterozygote for this mutation and the -87 promoter mutation; (2) a G-C substitution at position 844 of IVS-II, in a patient heterozygous for this mutation who showed normal sequences at the in trans beta-globin gene (The reason for the presence of clinical manifestations in a beta-thalassemia heterozygote has not been defined.); and (3) a deletion of one nucleotide (-T) at codon 126, resulting in a frameshift and readthrough of the 5' untranslated region and most likely producing an elongated Hb molecule of 156 amino acid residues, in a patient heterozygous for this mutation with normal beta-globin gene sequences at the other locus.

Adult↗