Hemoglobinopathies in the district of Antalya, Turkey

Biochemical and molecular analysis of the beta-globin gene and LCR region on Saudi β-thalassemia patients

Introduction

Beta-thalassemias are a group of inherited blood disorders caused by reduced or absent synthesis of beta chain of hemoglobin resulting in variable phenotypes ranging from clinically asymptomatic individuals to severe anemia symptoms. The objective of this study is to screen for the whole beta gene globulin and the LCR region and its clinical relevance in β-Thalassemia patients.

Methods

In this study, we collected 140 blood patients' samples with beta-thalassemia from different areas of Saudi Arabia. DNA was then extracted then the molecular scanning for the whole β-globin gene and the Locus control region (β-LCR) for patients' samples, was run using PCR.

Results

Sixty one mutations found in this study, including 22 new mutations not recorded in the database before. These deletions including: (*C-1960-1961 ca/-- del in hbb5) and (*c-519C<T homo, *c-390C<T homo in hbb6) were the highest among beta-thalassemia in the study, which indicates a strong sign of injury associated with the disease. Meanwhile, There are other mutations found most common among patients and was linked with the severity of clinical symptoms including: (c-1960-1961 ca/-- del in hbb5), (c-519C<T homo, c-390C<T homo, c-160 G<A het in hbb6), (c.315+282 G<A het, c.316-225G<A het, c.315+342 G > A het in hbb9). Interestingly, the highest percentage in gene deletion occurred in exon 03A by ∼33% of the samples, while the highest percentage in gene addition of the gene occurred in exon 03B by ∼25%.

Conclusion

This study was unique to show several new mutations that would help in diagnosis and treatment. These results should be taken further to set up better management strategies to improve outcomes.

Development of gene editing strategies for human β-globin (HBB) gene mutations

Recent developments in gene editing technology have enabled scientists to modify DNA sequence by using engineered endonucleases. These gene editing tools are promising candidates for clinical applications, especially for treatment of inherited disorders like sickle cell disease (SCD). SCD is caused by a point mutation in human β-globin gene (HBB). Clinical strategies have demonstrated substantial success, however there is not any permanent cure for SCD available. CRISPR/Cas9 platform uses a single endonuclease and a single guide RNA (gRNA) to induce sequence-specific DNA double strand break (DSB). When this accompanies a repair template, it allows repairing the mutated gene. In this study, it was aimed to target HBB gene via CRISPR/Cas9 genome editing tool to introduce nucleotide alterations for efficient genome editing and correction of point mutations causing SCD in human cell line, by Homology Directed Repair (HDR). We have achieved to induce target specific nucleotide changes on HBB gene in the locus of mutation causing SCD. The effect of on-target activity of bone fide standard gRNA and newly developed longer gRNA were examined. It is observed that longer gRNA has higher affinity to target DNA while having the same performance for targeting and Cas9 induced DSBs. HDR mechanism was triggered by co-delivery of donor DNA repair templates in circular plasmid form. In conclusion, we have suggested methodological pipeline for efficient targeting with higher affinity to target DNA and generating desired modifications on HBB gene.

A National Registry of Thalassemia in Turkey: Demographic and Disease Characteristics of Patients, Achievements, and Challenges in Prevention

Objective:

The Turkish Society of Pediatric Hematology set up a National Hemoglobinopathy Registry to demonstrate the demographic and disease characteristics of patients and assess the efficacy of a hemoglobinopathy control program (HCP) over 10 years in Turkey.

Materials and Methods:

A total of 2046 patients from 27 thalassemia centers were registered, of which 1988 were eligible for analysis. This cohort mainly comprised patients with β-thalassemia major (n=1658, 83.4%) and intermedia (n=215, 10.8%).

Results:

The majority of patients were from the coastal areas of Turkey. The high number of patients in Southeastern Anatolia was due to that area having the highest rates of consanguineous marriage and fertility. The most common 11 mutations represented 90% of all β-thalassemia alleles and 47% of those were IVS1-110(G->A) mutations. The probability of undergoing splenectomy within the first 10 years of life was 20%, a rate unchanged since the 1980s. Iron chelators were administered as monotherapy regimens in 95% of patients and deferasirox was prescribed in 81.3% of those cases. Deferasirox administration was the highest (93.6%) in patients aged <10 years. Of the thalassemia major patients, 5.8% had match-related hemopoietic stem cell transplantation with a success rate of 77%. Cardiac disease was detected as a major cause of death and did not show a decreasing trend in 5-year cohorts since 1999.

Conclusion:

While the HCP has been implemented since 2003, the affected births have shown a consistent decrease only after 2009, being at lowest 34 cases per year. This program failure resulted from a lack of premarital screening in the majority of cases. Additional problems were unawareness of the risk and misinformation of the at-risk couples. In addition, prenatal diagnosis was either not offered to or was not accepted by the at-risk families. This study indicated that a continuous effort is needed for optimizing the management of thalassemia and the development of strategies is essential for further achievements in the HCP in Turkey.

Prevalence of beta-thalassemia trait and abnormal hemoglobins in the province of Adıyaman, Turkey

BACKGROUND/AIMS

Thalassemia is one of the most common hereditary disorders in Turkey. The aim of this study was to determine the prevalence of the beta-thalassemia trait and abnormal hemoglobins in the province of Adıyaman in Turkey.

METHODS

The study included 3571 high school students of both sexes; aged 12-22 (mean 16.59 ± 1.34). After they received information about thalassemia, they were screened for beta-thalassemia and abnormal hemoglobin using complete blood count (CBC) and quantification of hemoglobin. Hemoglobin was fractionated using HPLC.

RESULTS

The beta-thalassemia trait was found in 38 students (1.06%), and abnormal hemoglobin in seven students (0.20%). Of the latter, four carried HbD Los Angeles, two HbS, and one HbE-Saskatoon.

CONCLUSION

The prevalence of the beta-thalassemia trait and abnormal hemoglobin in the province of Adıyaman is low, compared to the rest of Turkey. Our results seem to reflect the heterogeneity of beta-thalassemia in the province of Adıyaman and may be of value for genetic counseling and premarital screening.

Hematopoietic stem cell transplantation activity and trends at a pediatric transplantation center in Turkey during 1998-2008

Objective: The aim of this study was to document hematopoietic stem cell transplantation (HSCT) activity and trends at our treatment center.

Material and Methods: Data collected over a 10-year period were retrospectively analyzed, concentrating primarily on types of HSCT, transplant-related mortality (TRM), stem cell sources, indications for HSCT, and causes of death following HSCT.

Results: In total, 222 allogeneic (allo)-HSCT (87.4%) and 32 autologous (auto)-HSCT (12.6%) procedures were performed between 1998 and 2008. Stem cells obtained from unrelated donors were used in 22.6% (50/222) of the allo- HSCTs. Cord blood was the source of hematopoietic stem cells (HSC) in 12.2% of all transplants. The most common indication for allo-HSCT was hemoglobinopathy (43.2%), versus neuroblastoma (53.1%) for auto-HSCT. The TRM rate 1 year post transplantation was 18.3% ± 2.5% for all transplants, but differed according to transplantation type (23.5% ± 7.9% for auto-HSCT and 17.5% ± 2.6% for allo-HSCT). The most common cause of death 1 year post HSCT was infection (35.9%).

Conclusion: The TRM rate in the patients that underwent allo-HSCT was similar to that which has been previously reported; however, the TRM rate in the patients that underwent auto-HSCT was higher than previously reported in developed countries. The selection of these patients to be transplanted must be made attentively.

Molecular characterization of hemoglobin D Punjab traits and clinical-hematological profile of the patients

CONTEXT AND OBJECTIVE

Hemoglobin (Hb) D hemoglobinopathies are widespread diseases in northwestern India and usually present with mild hemolytic anemia and mild to moderate splenomegaly. The heterozygous form of Hb D is clinically silent, but coinheritance of Hb D with Hb S or beta-thalassemia produces clinically significant conditions like thalassemia intermedia of moderate severity. Under heterozygous conditions with coinheritance of alpha and beta-thalassemia, patients show a degree of clinical variability. Thus, our aim was to molecularly characterize the Hb D trait among individuals who were clinically symptomatic because of co-inheritance of alpha deletions or any beta-globin gene mutations.

DESIGN AND SETTING

This was a cross-sectional study conducted in an autonomous tertiary-care hospital.

METHODS

Complete blood count and red cell indices were measured using an automated cell analyzer. Quantitative assessment of hemoglobin Hb F, Hb A, Hb A2 and Hb D was performed by means of high performance liquid chromatography (HPLC). DNA extraction was done using the phenol-chloroform method. Molecular analyses on common alpha deletions and common beta mutations were done using the Gap polymerase chain reaction and Amplification Refractory Mutation System, respectively.

RESULTS

We evaluated 30 patients and found clinical variation in the behavior of Hb D traits. In six patients, the Hb D traits were clinically symptomatic and behaved like those of thalassemia intermedia. Molecular characterization showed that three out of these six were IVS-1-5 positive.

CONCLUSIONS

HPLC may not be the gold standard for diagnosing symptomatic Hb D Punjab traits. Hence, standard confirmation should include molecular studies.

A Confidential Inquiry Estimating the Number of Patients Affected with Sickle Cell Disease and Thalassemia Major Confirms the Need for a Prevention Strategy in The Netherlands

We have conducted a broad confidential inquiry among 401 hospital departments trying to estimate the number of patients affected with severe forms of hemoglobinopathies living in The Netherlands. With less than 30% response we have registered 559 patients in all age categories of whom 77.0% are affected with sickle cell disease and 17.5% with beta-thalassemia (thal) major. We estimate that the real figure could be around 800 patients, a figure more than six times higher than the number published in 1995 on which the reluctance to offer prevention was based. The actual figures and the incidence estimation of approximately 60 patients a year underline the urgent need for the official implementation of a prevention strategy in The Netherlands. During the last 5 years we have been working towards the implementation of a multi-intervention strategy for primary prevention using the existing structures of public health. The obstacles we have encountered to endorse such a strategy are discussed as a possible guide for other immigration countries.

Genetic Origin of Hb D-Los Angeles [β121(GH4)Glu→Gln,GAA→CAA] According to the β-Globin Gene Cluster Haplotypes

Hb D-Los Angeles (also known as D-Punjab, D-North Carolina, D-Portugal, D-Chicago and Oak Ridge) is an abnormal hemoglobin (Hb) with an amino acid substitution of glutamine for glutamic acid at codon 121 of the beta-globin gene. The origin and spread of Hb D-Los Angeles is not known. This is due to lack of information and remains to be elucidated. According to published reports, the Hb D-Los Angeles mutation is mostly linked with Mediterranean haplotype I [+ - - - - + +]. Besides the Mediterranean haplotype, a novel haplotype was also reported from Thailand [- - + + - - + + +]. Here we report a new haplotype from Turkey [- + -- + + +] that has not been described before. These results suggest that the Hb D-Los Angeles mutation has at least three different genetic origins.

Hemoglobin variants in Cyprus

Cyprus, located at the eastern end of the Mediterranean region, has been a place of eastern and western civilizations, and the presence of various hemoglobin (Hb) variants can be considered a testimony to past colonizations of the island. In this study, we report the structural Hb variants identified in the Cypriot population (Greek Cypriots, Maronites, Armenians, and Latinos) during the thalassemia screening of 248,000 subjects carried out at the Thalassaemia Centre, Nicosia, Cyprus, over a period of 26 years. A sample population of 65,668 people was used to determine the frequency and localization of several of the variants identified in Cyprus. The localization of some of the variants in regions where the presence of foreign people was most prevalent provides important clues to the origin of the variants. Twelve structural variants have been identified by DNA sequencing, nine concerning the beta-globin gene and three concerning the alpha-globin gene. The most common beta-globin variants identified were Hb S (0.2%), Hb D-Punjab (0.02%), and Hb Lepore-Washington-Boston (Hb Lepore-WB) (0.03%); the most common alpha-globin variant was Hb Setif (0.1%). The presence of some of these variants is likely to be directly linked to the history of Cyprus, as archeological monuments have been found throughout the island which signify the presence for many years of the Greeks, Syrians, Persians, Arabs, Byzantines, Franks, Venetians, and Turks.

Prevalence and hematological characteristics of beta-thalassemia trait in Gaziantep urban area, Turkey

Thalassemia is one of the most common hereditary disorders in the Mediterranean region and studies have shown that the prevalence of beta-thalassemia trait is high in the southern part of Turkey. Gaziantep is a city located near this region and, therefore, the authors investigated the prevalence and hematological characteristics of the beta-thalassemia traits in primary school students in Gaziantep. Sixty primary schools were selected from a list of all primary schools using a systematic sampling method. Data were collected by a face-to-face questionnaire. Osmotic fragility testing (OFT) using single-tube 0.36% NaCl solution was used for the screening of beta-thalassemia. Students who were positive in regard to OFT went through a series of testing, including a complete blood count, serum ferritin levels, serum iron, and hemoglobin electroforesis. Chi-square test was used in statistical analysis. Of the 2439 students enrolled to the study from the selected 60 classrooms, 1353 (55.5%) were male and 1086 (44.5%) were female. The OFT was positive in 115 (4.7%) of the participants. CEA and confirmatory HPLC results of the students who were positive OFT indicated that 70 (60.8%) had normal results, 33(28.7%) showed high HbA2 levels, 7 (6.1%) showed high HbA2 and HbF levels, 5(5.2%) showed high HbA2 and Fe-deficiency anemia, and none showed increased HbF levels. The overall prevalence of beta-thalassemia trait was 1.84%. No gender differentials and highest rates among the Kahramanmaras (3.5%) and Sanliurfa (1.7%) born students were the other significant findings of this study. Implementation of a routine carrier-screening program offering genetic counseling, prenatal diagnosis, and selective termination of affected fetuses would be a wise approach to eliminate this disease from the region.

High incidence of Hb D-Los Angeles [beta121(GH4)Glu-->Gln] in Denizli Province, Aegean region of Turkey

Denizli Province is located in the inner part of the Aegean region of Turkey and is one of the target areas for premarital screening. Here we report the abnormal hemoglobins (Hbs) observed during a premarital screening program in our region. According to our results, Hb D-Los Angeles [beta1211(GH4)Glu-->Gln (GAA-->CAA] (also known as D-Punjab, D-North Carolina, D-Portugal, Oak Ridge and D-Chicago), is the most frequent abnormal Hb in this region.

Two rare mutations in Turkey: IVS I.130(G-C) and IVS II.848(C-A)

Beta-thalassemia, an autosomal recessive disease, results from mutations of the beta-globin gene. More than 40 different mutations found in Turkish beta-thalassemia patients are mostly composed of point mutations, and only in very rare cases a deletion or an insertion causes beta-thalassemia phenotypes. Here, we report two patients who were clinically diagnosed with beta-thalassemia major and HbS/beta-thalassemia respectively. We performed reverse dot blot hybridization method and automated sequence analysis to detect the mutations. One of the patients was found to be IVS I.130 (G-C) homozygous, the other was HbS/IVS II.848 (C-A) as compound heterozygous. The aim of this study was to report hematological and clinical findings in both cases related with beta-globin gene defects that are very rare.

Peripheral blood stem cell transplantation in children with beta-thalassemia

Fifteen patients with beta-thalassemia received an allogeneic peripheral blood stem cell transplant. Median age was 3.5 years (1-15 years). Six were class I, four class II and five class III according to the Pesaro criteria. All of the donors were HLA-phenotypically identical (13 siblings and two parents). Nine patients were given BU + CY and six BU + CY plus ATG as conditioning. All patients received MTX (+1, +3, +6) and CsA (9-12 months) post transplant for GVHD prophylaxis. The median neutrophil and platelet engraftment times were day 12 and day 16, respectively. cGVHD was observed in three patients. Two patients died. Thirteen patients are well, and transfusion-independent 2-30 months after PSCT. No recurrences of thalassemia have been seen. Overall and event-free survival were 86.6%. In conclusion, we suggest that PSCT can be considered a safe and effective treatment for children with beta- thalassemia.

Rheumatological manifestations of haematological diseases

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