EFFECT OF CIS ACTING POTENTIAL REGULATORS IN THE ß GLOBIN GENE CLUSTER ON THE PRODUCTION OF HBF IN THALASSEMIA PATIENTS

The clinical presentation of b-thalassemia intermedia phenotypes are influenced by many factors .The persistence of fetal hemoglobin and several polymorphisms located in the promoters of g- and b-globin genes are some of them .The aim of this study was to evaluate the combined effect of the -158Gg (CàT) polymorphism and of the (AT)x(T)y configuration, as well as their eventual association with elevated levels of HbF in b-thalassemia carriers, b-thalassemia Intermedia , b-thalassemia major and normal controls of Indian origin. The -158 Gg T allele was found to be associated with increased levels of HbF in b-thalassemia carriers, and not in wild-type subjects. In the homozygous group the -158 Gg T allele was significantly higher in the thalassemia intermedia group (66%) as against the thalassemia major group (21%). The (AT)9(T)5 allele did not show any association with raised HbF levels. However 24% of milder cases showed presence of this allele. This study suggests that two regions of the b globin cluster, whether in cis or in trans to each other, can interact to enhance HbF expression when a b thalassemic determinant is present in heterozigosity and help in amelioration of the severity of the disease in homozygotes.

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A silencer element from the alpha-globin gene inhibits expression of beta-like genes

Molecular and Cellular Biology ◽

10.1128/mcb.8.11.5047-5051.1988 ◽

1988 ◽

Vol 8 (11) ◽

pp. 5047-5051

Author(s):

G F Atweh ◽

J M Liu ◽

H E Brickner ◽

X X Zhu

Keyword(s):

Globin Gene ◽

Expression System ◽

Globin Genes ◽

Beta Globin ◽

Base Pair Fragment ◽

Alpha Globin ◽

In Trans ◽

Cis And Trans ◽

In Cis ◽

Silencer Element

We have studied the cis and trans interactions of the alpha- and beta-globin genes in a transient expression system. We found that the alpha-globin gene inhibited beta-globin expression in cis but not in trans. The silencer element responsible for this inhibition was localized to a 259-base-pair fragment at the 5' end of the alpha-globin gene.

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Differences in Fetal Hemoglobin Induction in Sickle Cell Disease and beta-Thalassemia.

Blood ◽

10.1182/blood.v108.11.555.555 ◽

2006 ◽

Vol 108 (11) ◽

pp. 555-555 ◽

Cited By ~ 2

Author(s):

Hassana Fathallah ◽

Ali Taher ◽

Ali Bazarbachi ◽

George F. Atweh

Keyword(s):

Gene Expression ◽

Sickle Cell Disease ◽

Globin Gene ◽

Fetal Hemoglobin ◽

Mrna Levels ◽

Globin Genes ◽

Thalassemia Intermedia ◽

Cell Disease ◽

Globin Mrna ◽

Globin Gene Expression

Abstract A number of therapeutic agents including hydroxyurea, butyrate and decitabine have shown considerable promise in the treatment of sickle cell disease (SCD). However, the same agents have shown less clinical activity in β-thalassemia. As a first step towards understanding the molecular basis of the different clinical responses to these agents, we have studied the mechanisms of induction of fetal hemoglobin (HbF) by butyrate in BFU-E derived cells from 5 patients with SCD and 9 patients with β-thalassemia intermedia. Exposure to butyrate resulted in a dose-dependent augmentation of γ-globin mRNA levels in erythroid cells from patients with SCD. In contrast, induction of γ-globin expression in erythroid cells from patients with β-thalassemia intermedia was only seen at a high concentration of butyrate. The increase in γ-globin mRNA levels in patients with SCD and β-thalassemia intermedia was associated with opening of the DNA structure as manifested by decreased DNA methylation at the γ-globin promoters. Interestingly, butyrate exposure had markedly different effects on the expression of the β- and α-globin genes in the two categories of patients. Butyrate decreased the level of β-globin mRNA in 4 out of 5 patients with SCD (P = 0.04), while in β-thalassemia the levels of β-globin mRNA did not change in 7 patients and decreased in 2 patients after butyrate exposure (P = 0.12). Thus in patients with SCD, the effects of the induction of the γ-globin gene on the γ/(β+γ) mRNA ratios were further enhanced by the butyrate-mediated decreased expression of the β-globin gene. As a result, γ/(β+γ) mRNA ratios increased in all patients with SCD, with a mean increase of 31% (P = 0.002). In contrast, butyrate increased γ/(β+γ) mRNA ratios only in 4 out of 9 patients with β-thalassemia, with a more modest mean increase of 12% (P = 0.004). Interestingly, the decreased β-globin expression in patients with SCD was associated with closing of the DNA configuration as manifested by hypermethylation of DNA at the promoter of the β-globin gene while methylation of the same promoter did not change following butyrate exposure in patients with β-thalassemia intermedia. More surprisingly, the expression of the α-globin genes increased following butyrate exposure in 4 out of 9 patients with β-thalassemia, while the levels of α-globin mRNA decreased in 4 out of 5 patients with SCD. As a result, the favorable effects of the butyrate-induced increase in γ-globin gene expression on the α: non-α mRNA imbalance in patients with β-thalassemia intermedia were partly neutralized by the corresponding increase in α-globin gene expression. These differences may explain, at least in part, the more favorable effects of inducers of HbF in SCD than in β-thalassemia. Further studies are necessary to fully understand the molecular bases of the different responses to agents that induce HbF in patients with these disorders.

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Analysis of (δβ)0 Thalassemia and HPFH Deletions Suggest a Hierarchy of Cis-Acting Elements Regulating Fetal Hemoglobin Gene Expression.

Blood ◽

10.1182/blood.v124.21.54.54 ◽

2014 ◽

Vol 124 (21) ◽

pp. 54-54 ◽

Cited By ~ 1

Author(s):

Heather L Edward ◽

Tasha Morrison ◽

Jacqueline N Milton ◽

Hong-yuan Luo ◽

Lance Davis ◽

...

Keyword(s):

Gene Expression ◽

Binding Site ◽

Conflicts Of Interest ◽

Globin Gene ◽

Regression Tree ◽

Fetal Hemoglobin ◽

Regulatory Elements ◽

Globin Genes ◽

Cis Acting ◽

Cart Analysis

Abstract Hereditary persistence of fetal hemoglobin (HPFH) and (δβ)0 thalassemia are caused by deletions within the β-globin gene (HBB) cluster that remove elements that affect the expression of the γ-globin genes (HBG2 and HBG1, or HBG). These deletions are of different lengths and have different 5’ and 3’ breakpoints. The phenotypes associated with heterozygous carriers of (δβ)0 thalassemia and HPFH deletions are differentiated by levels of 5-15% HbF distributed heterocellularly in the former and 15-30% HbF distributed pancellularly in the latter. We found a novel 588.6 kb deletion that removed both the 3.5 kb fragment 5’ to HBD that is deleted in Corfu β thalassemia and contains a BCL11A binding site, and the known cis-acting elements downstream of HBB. The proband with this deletion had a HbF of 5.4% (Morrison et al, Blood, 2014 abstract 3452). To study the relative importance of 5’ and 3’ regulatory elements in HBG expression we studied 209 cases culled from the literature and from our laboratory where the 3.5 kb element 5’ to HBD and enhancers 3’ to HBB were deleted and HBG remained intact. We used a backwards stepwise regression statistical analysis to determine which deleted elements had the greatest effect on HbF levels. The combination of the deletion of 3.5 kb intergenic region 5’ to HBD, the presence of the HPFH-1 “3D” enhancer juxtaposed to HBG, and the deletion of the 3’ HS1 region accounted for 66.7% of the HbF variation in heterozygotes for HPFH and (δβ)0-thalassemia deletions. The HPFH-1 “3D” enhancer juxtaposed to HBG— the main difference between HPFH-1 and 2 compared with Spanish (δβ)0-thalassemia—was associated with an increase in HbF of 20.78% (p<2e-16) after adjusting for the effects of the other 5’ and 3’ cis-acting elements. The next most significant factor was the deletion of the 3.5 kb fragment 5’ to HBD which resulted in an increase of 10.62% HbF after similar adjustments (p<2e-16); deletion of the 3’ HS1 region accounted for an increase in HbF of 5.25% (p<1.05e-5). The HPFH-3 and HPFH-6 enhancer regions each accounted for a less than 1% increase in HbF and were not significantly associated with HbF in this model. Among 194 individuals where both 5’ and some 3’ elements affecting γ-globin gene expression—excluding the “3D” enhancer—were deleted, HbF was 20±9.3%; in 13 cases where all 3’ enhancers—including the “3D” enhancer—were deleted, HbF was 6.8±3.7% (p=8.9e-07). To determine which combinations of cis-acting elements were associated with high and low HbF levels we performed a classification and regression tree (cART) analysis on HbF. The results of the regression tree (Figure) only included the deletion of the 5’ 3.5 kb fragment region, the presence of the HPFH-1 “3D” enhancer and the deletion of the 3’ HS1 region and were consistent with the results of the backwards selection model. The absence of the 5’ 3.5 kb fragment 5’ to HBD combined with the presence of the HPFH-1 “3D” enhancer was associated with the highest average HbF of 27.02%. The absence of the 3.5 kb fragment 5’ to HBD combined with the absence of the HPFH-1 “3D” enhancer was associated with the lowest average HbF of 6.82%.The 588.6 kb deletion is the largest deletion reported in the HBB cluster that leaves the γ-globin genes intact, and the second to remove both the BCL11A binding site and all known 3’ enhancer elements. By studying deletions in the HBBgene cluster we have further defined the hierarchy of cis-acting elements that modulate HbF levels in adults and suggest a paramount role of the distal “3D” enhancer. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

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A Deletion Of About 11kb Starting From 0.5 Kb 5’ To The β-Globin Gene Reactivates Foetal Haemoglobin and Leads To β Thalassemia Intermedia When Associated To a β-Zero Thalassemic Mutation

Blood ◽

10.1182/blood.v122.21.4702.4702 ◽

2013 ◽

Vol 122 (21) ◽

pp. 4702-4702

Author(s):

Photis Beris ◽

Tanguy Araud ◽

Lorella Clerici ◽

Anne-Pascale Grandjean ◽

Georgios Georgiou ◽

...

Keyword(s):

Conflicts Of Interest ◽

Globin Gene ◽

Thalassemia Major ◽

Globin Genes ◽

Beta Globin ◽

Thalassemia Intermedia ◽

Chromosome 11 ◽

Exact Size ◽

Hg19 Assembly

Background and Aims Thalassemia intermedia is characterized by severe but not transfusion dependent anemia secondary to seriously decreased production of hemoglobin (Hb). In the majority of cases, thalassemia intermedia concerns β-globin gene pathology. The molecular basis of thalassemia intermedia is heterogeneous. Here we describe a case of an adopted child native of Myanmar suffering from β-thalassemia intermedia which was proved to be secondary to a β-zero thalassemia associated with a not yet described deletional form of HPFH. Patient, Material and Methods Male child born in 1994 with Hb varying between 50 and 60 g/l, with Hb A2 of 2.1% and Hb F of 97.9%. No α-thalassemia or α-gene triplication was found. Sequencing of β-globin gene put in evidence the IVS-I-1 (G>T) or c.92+1G>T mutation in a “homozygous” state. This mutation is known to produce a β-zero thalassemia. The patient was treated with hydroxyurea as well as with erythropoietin and the Hb value was improved up to 86 g/l with normal leucocytes and platelets count. No transfusion was given during this period of treatment. Because the clinical phenotype was not typical for β-thalassemia major homozygous for the above mentioned mutation, we analyzed β-globin cluster looking for the presence of a possible deletion responsible for Hb F activation. Patient’s DNA was extracted with commercial columns from peripheral blood cells. Analysis of deletion in the beta cluster was performed by MLPA (Multiplex Ligation Probe Analysis) MRC-Holland P-102 probe mix. The data obtained were analyzed with the Coffyanalyzer software. The exact size of the deletion was determined by PCR with the primers: DelHBB_F: 5’-AGGCTTGGCTCCTGTTTAGT-3’, DelHBB_R: 5’-TGAGAG CTGCTGAGTTGTGT-3’ Results A heterozygous deletion in the beta-globin cluster has been detected by MLPA. This deletion was located between the coordinated 5,237,089 and 5,251,133 on chromosome 11 - (GRCh37/hg19 Assembly). The deletion starts about 0.5 kb 5’ upstream the HBB gene, between HBB and HBD genes, and ends about 9 kb downstream the 3’ end of HBB gene. The density of the MLPA probes is not sufficient to determinate the exact size of the deletion (between 14.3kb and 9.6 kb). A PCR using the primers DelHBB_F and DelHBB_R determined the size of this deletion to around 11kb. Conclusions Our molecular biology studies confirmed our clinical suspicion of association of HPFH with β-zero thalassemia. In fact, we put in evidence a not yet described (to our knowledge) 11kb deletion, which is very similar to the 12.6kb deletion of the Dutch β-zero thalassemia (Br J Haematol 67:369;1987) and to the Asian Indian 10.3kb deletion described by Craig et al (Br J Haematol 82:735;1992). Our deletion starts between δ and β-globin gene, almost 0.5 kb upstream of the β-gene, and goes about 9 kb downstream of 3’ end of the β-gene. The exact borders of the deletion are currently under investigation by PCR and appropriate primers. The pathophysiology of reactivation of γ-globin genes in our case is not yet known. We raise the following hypothesis: does this deletion bring an enhancer located 3’ to β-globin gene, close enough to the γ-genes, so that transcription of these genes continues after birth? In vitro studies in expression systems (constructs) are currently performed to elucidate the exact mechanism of γ-globin activation. Disclosures: No relevant conflicts of interest to declare.

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A silencer element from the alpha-globin gene inhibits expression of beta-like genes.

Molecular and Cellular Biology ◽

10.1128/mcb.8.11.5047 ◽

1988 ◽

Vol 8 (11) ◽

pp. 5047-5051 ◽

Cited By ~ 5

Author(s):

G F Atweh ◽

J M Liu ◽

H E Brickner ◽

X X Zhu

Keyword(s):

Globin Gene ◽

Expression System ◽

Globin Genes ◽

Beta Globin ◽

Base Pair Fragment ◽

Alpha Globin ◽

In Trans ◽

Cis And Trans ◽

In Cis ◽

Silencer Element

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β-Intermediate Thalasemia: triplication of genes α / β thalassemia heterozygous in Spain

ANALES RANM ◽

10.32440/ar.2021.138.01.rev07 ◽

2021 ◽

Vol 138 (138(01)) ◽

pp. 60-71

Author(s):

Paloma Ropero ◽

Fernando Ataulfo González Fernández ◽

Jorge Martínez Nieto ◽

Williana Melissa Torres Jiménez ◽

Celina Benavente Cuesta

Keyword(s):

Hematological Parameters ◽

Globin Gene ◽

Fetal Hemoglobin ◽

Globin Genes ◽

Thalassemia Intermedia ◽

Transfusion Therapy ◽

Group Iii ◽

Group I ◽

Caucasian Origin ◽

Group Ii

Objectives. Check with hematological data that the diagnosis and clinical grade of β-thalassemia intermedia can be established when a triplication of genes alpha (αααanti 3.7) and heterozygous β-thalassemia are coherent. Methods. Retrospective study in which 73 patients of Caucasian origin participated, who simultaneously showed a tripling or quadrupling of the genes α and heterozygous β-thalassemia. Screening for the most frequent α-thalassemia mutations, as well as gene triplication (αααanti 3.7) was carried out by multiplex PCR followed by reverse hybridization and confirmed by MLPA. The molecular diagnosis of β-thalassemia was carried out by automatic sequencing according to the Sanger’s method. Results. Genotypes have been classified into three groups according to the number of α-globin genes and the severity of the alteration in the β-globin gene. All had a mutation in the β-globin gene (β0-thalassemia, severe β+-thalassemia, and mild β+-thalassemia). Group I patients who have inherited 6 α globin genes. Group II and group III have inherited 5 α globin genes. In group III, the patients were carriers of mutations affecting the β and δ globin genes. The most significant hematological parameters were hemoglobin levels, mean corpuscular volume, red deep width, and percentage of fetal hemoglobin. Conclusions. In group I, patients who have inherited of 6 α globin genes, either by homozygous triplication (ααα/ααα) or heterozygous quadruplication (αααα/αα), with heterozygous β-thalassemia results in severe to moderate anemia that may require transfusion therapy, being the severity of the β-globin gene mutation that would determine the clinical variation. Group II patients behaved phenotypically like mild thalassemia intermedia. Finally, group III patients behaved like a thalassemic trait since all were carriers of mutations that increase the overexpression of g genes.

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Hemoglobin H Hydrops Fetalis Associated with Homozygous Hemoglobin Constant Spring. Case Report.

Blood ◽

10.1182/blood.v106.11.3821.3821 ◽

2005 ◽

Vol 106 (11) ◽

pp. 3821-3821

Author(s):

Monica V.E. Gallivan ◽

Emmanuel J. Vlastos ◽

Robin D. Hanson ◽

Maria P. Bettinoti ◽

Steven A. Schonberg ◽

...

Keyword(s):

Gene Dosage ◽

Post Partum ◽

Globin Gene ◽

Gene Sequencing ◽

Globin Genes ◽

Hb E ◽

Hb H Disease ◽

In Trans ◽

In Cis ◽

Hemoglobin Constant Spring

Abstract While Barts hydrops is predicted when all 4 α globin genes are absent or non functional, hydrops has rarely been described with a hemoglobin H (Hb H) genotype. Hb H disease has a varied hematologic phenotype ranging from asymptomatic to transfusion dependant. The severest clinical expression is non immune hydrops and may result in fetal demise. The commonest form of Hb H disease is deletional-type. This occurs when there is deletion of α2 and α1 genes in cis and deletion of either α2 or α1 in trans. The less frequent type, but clinically more severe, is non-deletional. This is usually due to a mutation in either α2 or α1 in cis and a deletion of both α2 and α1 in trans. There are rare reports of non-deletional Hb H due to homozygous α2 mutations without any α1 deletions or mutations. Heretofore, there have been no reports of hydrops with homozygous hemoglobin Constant Spring (Hb CS). A 31-year-old Laotian woman presented at 22 weeks with polyhydramnios. Besides this, the pregnancy was uneventful for the mother. On ultrasound the fetus had a pericardial effusion and signs of congestive heart failure. The hematological and genotypic parameters of the parents and fetus are outlined in table 1. Intrauterine transfusions were performed at 22 and 29 weeks. A male infant was born vaginally at 36 weeks gestation weighing 2.3 kg. The hemoglobin was 15.9 g/dL and bilirubin was 8.4mg/dL. There was no evidence of maternofetal alloimmunization. G6PD screen was negative. By 4 weeks post-partum, the bilirubin had decreased to 0.9 mg/dL but the hemoglobin had progressively fallen to 6.9 g/dL, requiring transfusion. He had two additional transfusions at 6 and 8 weeks of life but has subsequently maintained a hemoglobin above 10 g/dL and has steadily gained weight. As in this patient, the genotypes of the other reported cases of Hb H hydrops are usually associated with a thalassemia intermedia phenotype. Thus the α globin genotypes alone do not explain why hydrops occurs. This suggests that there may be unknown genetic and/or acquired modifiers contributing to the severity of Hb H disease that results in hydrops as in this fetus with homozygous Hb CS. [Table 1] Mother Father Fetus at 22 weeks Hemoglobin g/dL 10.0 12.5 5.2 MCV fL 86.3 81.8 143.8 MCH pg 26.5 25.6.8 46.4 RDW % 16.7 13.6 21.4 Reticulocyte % 9.9 ND 19.0 NRBC/100WBC 1 0 4756 Hemoglobin Fractions by HPLC Hb A 73.3% 97.8% 3.4% Hb F 0.8% 0.0% 77.7% Hb A2 0.9% 2.1% 0.0% Barts 0.0% 0.0% 17.7% Hb Constant Spring 2.8% 0.1% 1.2% Hb E 22.2% 0.0% 0.0% αGlobin Gene Dosage Assay by Linear PCR 4 4 4 αGlobin Gene Deletions by PCR - 3.7, - 4.2, _SEA, - 20.5, _MED,_FIL,_THAI None detected None detected None detected α2 Globin Gene Sequencing α-2CS/α-2CS α-2CS/WTα-2CS/α-2CS α1 Globin Gene Sequencing WT/WT WT/WT WT/WT βGlobin Gene Sequencing Heterozygous Hb E WT/WTWT/WT E

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Therapeutic levels of fetal hemoglobin in erythroid progeny of β-thalassemic CD34+ cells after lentiviral vector-mediated gene transfer

Blood ◽

10.1182/blood-2010-08-300723 ◽

2011 ◽

Vol 117 (10) ◽

pp. 2817-2826 ◽

Cited By ~ 69

Author(s):

Andrew Wilber ◽

Phillip W. Hargrove ◽

Yoon-Sang Kim ◽

Janice M. Riberdy ◽

Vijay G. Sankaran ◽

...

Keyword(s):

Gene Transfer ◽

Lentiviral Vector ◽

Globin Gene ◽

Fetal Hemoglobin ◽

Thalassemia Major ◽

Gene Promoters ◽

Globin Genes ◽

Enhanced Production ◽

Cd34 Cells

Abstract β-Thalassemia major results from severely reduced or absent expression of the β-chain of adult hemoglobin (α2β2;HbA). Increased levels of fetal hemoglobin (α2γ2;HbF), such as occurs with hereditary persistence of HbF, ameliorate the severity of β-thalassemia, raising the potential for genetic therapy directed at enhancing HbF. We used an in vitro model of human erythropoiesis to assay for enhanced production of HbF after gene delivery into CD34+ cells obtained from mobilized peripheral blood of normal adults or steady-state bone marrow from patients with β-thalassemia major. Lentiviral vectors encoding (1) a human γ-globin gene with or without an insulator, (2) a synthetic zinc-finger transcription factor designed to interact with the γ-globin gene promoters, or (3) a short-hairpin RNA targeting the γ-globin gene repressor, BCL11A, were tested. Erythroid progeny of normal CD34+ cells demonstrated levels of HbF up to 21% per vector copy. For β-thalassemic CD34+ cells, similar gene transfer efficiencies achieved HbF production ranging from 45% to 60%, resulting in up to a 3-fold increase in the total cellular Hb content. These observations suggest that both lentiviral-mediated γ-globin gene addition and genetic reactivation of endogenous γ-globin genes have potential to provide therapeutic HbF levels to patients with β-globin deficiency.

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An HPFH Mutation in the γ-Globin Gene Promoter of Humanized Cooley's Anemia Mice Rescues Them from Perinatal Lethality and Renders Them Transfusion Independent

Blood ◽

10.1182/blood.v128.22.1290.1290 ◽

2016 ◽

Vol 128 (22) ◽

pp. 1290-1290

Author(s):

Suean Daimia Fontenard ◽

Yongliang Huo ◽

Shanrun Liu ◽

Jonathan Lockhart ◽

Michael Berlett ◽

...

Keyword(s):

Conflicts Of Interest ◽

Therapeutic Option ◽

Globin Gene ◽

Gene Promoter ◽

Fetal Hemoglobin ◽

Thalassemia Major ◽

Globin Genes ◽

Humanized Mouse Model ◽

Perinatal Lethality ◽

Cooley's Anemia

Abstract Cooley's Anemia (CA), β-thalassemia major, is a genetic disease caused by an impairment in β-globin protein synthesis. The resulting excess in α-globin chains causes the premature destruction of erythroid cells (ineffective erythropoiesis), anemia, and if left untreated, death within the first years of life. Several mutations in the promoters of the fetal γ-globin genes have been identified which impair the silencing of the fetal genes in adulthood, a condition termed hereditary persistence of fetal hemoglobin (HPFH). The amount of fetal hemoglobin (Hb F) expressed and the distribution within the RBC population (pancellular vs heterocellular), varies widely with different HPFH mutations. It has also been observed that thalassemia patients who co-inherit HPFH mutations that express higher levels of Hb F have milder disease symptoms. The purpose of this study is to determine whether the incorporation of a non-deletional HPFH mutation into the promoter of the human g-globin gene in a humanized mouse model of CA can rescue the animals from their perinatal lethality. Heterozygous humanized HPFH -175 mice express pancellular, high-levels of Hb F into adulthood. Homozygous HPFH -175 CA mice are rescued from their perinatal lethality, surviving solely on 100% human Hb F and are transfusion independent for life. This result is significant because it demonstrates that introduction of an HPFH mutation into the γ-globin gene promoter by gene editing may be a viable therapeutic option for CA patients in the future. Disclosures No relevant conflicts of interest to declare.

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beta-thalassemia intermedia in a Brazilian patient with - 101(C > T) and codon 39 (C > T) mutations

Sao Paulo Medical Journal ◽

10.1590/s1516-31802003000100007 ◽

2003 ◽

Vol 121 (1) ◽

pp. 28-30

Author(s):

Sylvia Morais de Sousa ◽

Letícia Khater ◽

Luís Antônio Peroni ◽

Karine Miranda ◽

Marcelo Jun Murai ◽

...

Keyword(s):

Clinical Course ◽

Globin Gene ◽

Fetal Hemoglobin ◽

Hypochromic Anemia ◽

Beta Thalassemia ◽

Beta Globin ◽

Thalassemia Intermedia ◽

Mean Cell Volume ◽

Molecular Alterations ◽

Brazilian Patient

CONTEXT: We verified molecular alterations in a 72-year-old Brazilian male patient with a clinical course of homozygous beta-thalassemia intermedia, who had undergone splenectomy and was surviving without regular blood transfusions. The blood cell count revealed microcytic and hypochromic anemia (hemoglobin = 6.5 g/dl, mean cell volume = 74 fl, mean cell hemoglobin = 24 pg) and hemoglobin electrophoresis showed fetal hemoglobin = 1.3%, hemoglobin A2 = 6.78% and hemoglobin A = 79.4%. OBJECTIVE: To identify mutations in a patient with the symptoms of beta-thalassemia intermedia. DESIGN: Molecular inquiry into the mutations possibly responsible for the clinical picture described. SETTING: The structural molecular biology and genetic engineering center of the Universidade Estadual de Campinas, Campinas, Brazil. PROCEDURES: DNA extraction was performed on the patient's blood samples. The polymerase chain reaction (PCR) was done using five specific primers that amplified exons and the promoter region of the beta globin gene. The samples were sequenced and then analyzed via computer programs. RESULTS: Two mutations that cause the disease were found: -101 (C > T) and codon 39 (C > T). CONCLUSIONS: This case represents the first description of 101 (C > T) mutation in a Brazilian population and it is associated with a benign clinical course.

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