Figure 1 - uploaded by Ali Bazi
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β globin gene cluster on chromosome 11. Locus control region (LCR) which contains four DNA hypersensitivity (HS) sites is the major site for interaction of erythroid specific transcription factors. Four active genes including ε, G, A, and β are mapped. Each of these genes expresses in certain periods of human development with the β gene as the main expressing gene in adulthood. Also, a pseudo β-like gene is located between A and genes.(adapted from Thein et al, 2013)(6).
Source publication
β-thalassemia major (β –TM) is the most common thalassemia severe phenotype among Iranians. In recent
years, molecular understanding of pathogenesis of β –TM has provided a great opportunity regarding diagnostic
issues. Creating comprehensive molecular databases provides highly sensitive diagnostic tools for β –TM and
effective prenatal diagnosi...
Context in source publication
Context 1
... addition to adult beta globin gene (HBB), HBB cluster contains 4 other expressing genes namely epsilon, A- gamma, G-gamma, and delta. Each gene demonstrates unique expression characteristics resulting in different hemoglobin profiles throughout life. Locus controlling region (LCR) roles as the main regulator sequence in switching between these active genes ( Figure 1). For more details, reader is referred to comprehensive reviews on expressional patterns of beta globin like genes (5). In addition to LCR, HBB contains a specific promoter sequence that provides higher levels of control on the gene expression. Furthermore, three exons and two introns (intervening sequence-IVS) are also present within the HBB which are targets for most mutations responsible for β -TM ...
Citations
... β-Talassemia is the most common form of transfusion-dependent thalassemia in Iran, especially in the south and north regions with a carrier frequency of more than 10% [4][5][6]. Since the start of premarital carrier screening programs in 1991, a signifcant reduction has been observed in the emergence of new cases in most regions of the country [7]. However, there are still some problems in controlling the birth of new subjects [8]. ...
... 5 Mean corpuscular hemoglobin concentration. 6 Red blood cell distribution width. At the present study, we aimed to present the frst report of a case with thalassemia intermedia who coinherited the c.315 + 1 G > A pathogenic variant and a novel variant (HBB: c.-19 G > C) that was missed during the screening program. ...
Up to now, more than 300 pathogenic variants have been identified in the β-globin gene, some of which are categorized as silent mutations that do not change the hematological indices. In the present study, our aim is to introduce the first report of a case with thalassemia intermedia with coinheritance of the c.315 + 1 G > A pathogenic variant and a silent variant (HBB: c.-19 G > C) that was missed during the screening program. Multiplex-Gap-PCR and Sanger sequencing methods were applied to identify α- and β-globin gene mutations in a 26-year-old male subject with diagnosis of thalassemia. The identified mutations were also checked on the parent’s sample. The CBC and capillary electrophoresis tests were performed on the parent’s blood samples. The case was compound heterozygote for the c.315 + 1 G > A and c.-19 G > C (rs1239893012) variants. The subject’s mother carried the c.-19 G > C variant in the β-globin gene while her CBC and electrophoresis test results showed a normal pattern. Silent mutations are susceptible to being missed during premarital screening of β-thalassemia carriers, and the c.-19 G > C variant is recommended to be classified as a pathogenic variant in the β-globin gene.
... About 3% (150 million) of the world's population are β-thalassemia patients and by 2018, 30,000 β-thalassemia patients lived in Iran and this increased by nearly 1,000 people every year (Shahsavari et al., 2022). β-thalassemia is the most common type in Iran (Bazi and Miri-Moghaddam, 2016). ...
... A demographic questionnaire and a Knowledge, Attitude and Performance Scale for β-thalassemia (KAPSBT) were used for data collection. The demographic profile questionnaire consisted of age, gender, education level, residence, insurance status, items (6,8,9,10,11,12,14), the nutrition program with 2 items (13,15) The control group only received the routine training of the clinic, but after completing post-test questionnaires, the care plan pamphlets were given to them. Zabol University of Medical Sciences was approved the study with code IR.ZBMU.REC.1401.008. ...
... This mutation affects RNA splicing and results in the β-thalassemia major phenotype. Notably, IVS-1-5 (G > C) is the most prevalent mutation in the northeast of Iran in the Khorasan province [11]. Here we describe the molecular design and proof-ofconcept analysis of gene constructs created to correct the IVS-1-5 G > C mutation in β-thalassemia patients-derived HSCs using the HDR-based CRISPR/Cas9 gene-editing strategy. ...
Beta-thalassemia is one of the most common monogenic inherited disorders worldwide caused by different mutations in the hemoglobin subunit beta (HBB) gene. Genome-editing based on clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 system (CRISPR/Cas9) has raised the hope for life-long gene therapy of beta-thalassemia. In a proof-of-concept study, we describe the detailed design and assess the efficacy of a novel homology-directed repair (HDR)-based CRISPR construct for targeting the HBB locus. The selected sgRNAs were designed and cloned into an optimized CRISPR plasmid. The HDR donor templates containing a reporter and a selection marker flanked by the piggyBac Inverted Tandem Repeat (ITRs), the homology arms and the delta thymidine kinase (ΔTK) gene for negative selection were constructed. The efficiency of on-target mutagenesis by the eSpCas9/sgRNAs was assessed by mismatch assays. HDR-positive cells were isolated by treatment with G418 or selection based on truncated Neuron Growth Factor Receptor (tNGFR) expression using the Magnetic Activated Cell Sorting (MACS) method followed by ganciclovir (GCV) treatment to eliminate cells with random genomic integration of the HDR donor template. In–out PCR and sanger sequencing confirmed HDR in the isolated cells. Our data showed ~ 50% efficiency for co-transfection of CRISPR/donor template plasmids in HEK293 cells and following G418 treatment, the HDR efficiency was detected at ~ 37.5%. Moreover, using a clinically-relevant strategy, HDR events were validated after selection for tNGFR+ cells followed by negative selection for ΔTK by GCV treatment. Thus, our HDR-based gene-editing strategy could efficiently target the HBB locus and enrich for HDR-positive cells.
... About 3% (150 million) of the world's population are β-thalassemia patients and by 2018, 30,000 β-thalassemia patients lived in Iran and this increased by nearly 1,000 people every year (Shahsavari et al., 2022). β-thalassemia is the most common type in Iran (Bazi and Miri-Moghaddam, 2016). ...
... A demographic questionnaire and a Knowledge, Attitude and Performance Scale for β-thalassemia (KAPSBT) were used for data collection. The demographic profile questionnaire consisted of age, gender, education level, residence, insurance status, items (6,8,9,10,11,12,14), the nutrition program with 2 items (13,15) The control group only received the routine training of the clinic, but after completing post-test questionnaires, the care plan pamphlets were given to them. Zabol University of Medical Sciences was approved the study with code IR.ZBMU.REC.1401.008. ...
Objectives: Most of the parents of thalassemia children do not have sufficient knowledge and proper attitude and performance in facing the process of their child's disease. One of the ways to reduce the problems of thalassemia patients is to improve the knowledge, attitude and performance of their parents to manage preventable problems through educational programs. Therefore, this study evaluated the impact of the teach-back care program on the knowledge, attitude and performance of parents of children with thalassemia. Methods: Sixty-two parents of children with β-thalassemia in Zabol, Iran participated in this quasi-experimental study. The samples were randomly assigned into intervention and control groups. A demographic questionnaire and a knowledge, attitude and performance scale for thalassemia patients were used for data collection. Results: The results of independent t-tests did not show a statistically significant difference in the knowledge and attitude scores before the intervention in the two intervention and control groups (P≥0.005). But after the intervention, a statistically significant difference was observed between the knowledge and attitude scores in the two groups (P≤0.001). Mann-Whitney U test, there was no statistically significant difference in the performance mean scores before the intervention in the two interventions and control groups (P≥0.005). However, after the intervention, a statistically significant difference was observed in the mean performance scores between the groups (P≤0.001). Conclusions: The results suggest the effectiveness of the teach-back method in improving the awareness, attitude and performance of parents of children with thalassemia in line with the implementation of their children's care plan.
... Iran is a vast country with high ethnic diversity. These factors have not only led to a high prevalence of a number of genetic diseases, but have also led to a wide range of mutations associated with each of these diseases [27][28][29][30][31][32]. The above issues are more evident in the western region of Iran [19][20][21][22][23][24][25][26][33][34][35][36][37][38]. ...
Background
It is difficult to classify a small fraction of α- and β-thalassemia (α- and β-thal) carriers based on their Hb A 2 levels. Here, we report the results of a molecular investigation in a cohort of thalassemia carriers with borderline Hb A 2 levels originated from western Iran.
Results
The documents of 5956 α- or β-thal carriers were reviewed. The frequency of individuals with borderline Hb A 2 levels in this cohort was 436 (7.32%). A total of 12 different α-thal and 27 different β-thal variants were identified in this study.
Conclusions
Our data showed that individuals with borderline Hb A 2 are not uncommon in our population. Moreover, preselection of α- and β-thal carriers with borderline Hb A 2 levels based on Hb A 2 , mean corpuscular volume (MCV), and mean cell hemoglobin (MCH) is not advisable in our population. Therefore, it is necessary to investigate both α- and β-globin genes in cases with borderline Hb A 2 levels, especially if the partner is a carrier of β-thal or α ⁰ -thal.
... On the other hand, Iran is a country with a population of about 85 million people as well as a high ethnic diversity [11][12][13][14][15][16][17][18]. In fact, recent studies have shown high mutational diversity of single-gene disorders in Iran [19][20][21][22][23]. From all the above issues, it is possible that the number of PTS gene variants in Iran increase in the future. ...
Background
6-Pyruvoyl-tetrahydropterin synthase (PTPS) deficiency is an autosomal recessive disorder caused by PTS gene mutations. The aim of this study was to collect all PTS gene variants detected among Iranian patients with PTPS deficiency as well as in the Iranome project and classify them based on American College of Medical Genetics and Genomics (ACMG-AMP) guidelines.
Results
The number of PTS gene variants reported among Iranian PTPS patients and in the Iranome project were 19 and 36, respectively. Given that one variant was reported in both of our sources, the total number of variants was 54. These variants were classified as pathogenic ( n = 11), likely pathogenic ( n = 7), VUS ( n = 23), likely benign ( n = 1), and benign ( n = 12). Out of 19 variants reported among Iranian PTPS patients, c.155A>G (p.Asn52Ser, rs104894275) and c.317C>T (p.Thr106Met, rs200712908) were the most frequent ones, each with a frequency of 10%. c.84-3C>G (rs1230781262) (7.5%) and c.281A>T (p.Asp94Val) (5%) were in the next ranks of the list of variants.
Conclusions
The ACMG-AMP criteria need to be updated depending on the type of disease. In addition, to the best of our knowledge, no template has been described for classifying the variants identified in PTPS deficiency. Therefore, this study can be a good reference for future studies in this subject.
... β-thalassemia is the most common inherited disease in Iran, especially in the southern and northern provinces (more than 10 % carrier frequency), [10][11][12]. A significant reduction was observed in the emergence of new cases in most regions of the country as the pre-marital carrier screening programs for thalassemia began in 1991, [6]. ...
This is a report of a couple with abnormal hematological indices who were investigated for α & β-thalassemia mutations. Based on CBC and capillary hemoglobin electrophoresis results, the male and female subjects were β & α-thalassemia carriers, respectively. Multiplex-Gap-PCR and Sanger sequencing techniques were used for the identification of mutations on α and β-globin genes. The DNA test showed the presence of c.315 + 1 G > A mutation on β-globin gene of male subject while the female case had – MED double gene deletion and c.427T > C mutation on α-globin and, interestingly, she was also a carrier for c.315 + 1 G > A mutation on β-globin gene. Cases with the coinheritance of heterozygous β0-thalassemia with one functional α-globin gene have normal HbA2 levels that may lead to their being misdiagnosed as β-thalassemia carriers, especially in premarital screening programs for thalassemia. Therefore, β-globin gene sequencing is recommended in cases with normal Hb electrophoresis and reduced hematological indices in premarital screening programs for thalassemia, especially in regions with a high frequency of β-globin mutations, in order to identify all the β-thalassemia carriers.
... At present, more than 300 mutations in β globin gene have been detected worldwide. The majority of these mutations are point mutations, but deletions have 48 International Journal of Hematology Oncology and Stem Cell Research ijhoscr.tums.ac.ir been reported 5 . Some of these mutations result in deficient synthesis of β chain (β + thal), and others lead to complete absence of β globin (β thal). ...
... The second prevalent mutation is IVS I -5 (G > C) mutation (7.55%), and codon 8/9 (+G) and IVS I -110 (G > A) were the other most common mutations 4 . Also, other studies have shown that IVS II -1 and IVS I -5 are the two common β gene mutations in Iran 5,7,8 . In a recent survey about different β globin gene mutations in Iran, other relatively prevalent mutations include frame shift (FS) mutations in codon 8/9 (+G), IVS I -110 (G>A), FSC 36/37 (-T), IVS I -I (G>A), IVS I (-25 bp), and codon 44 (-C) 5 . ...
... Also, other studies have shown that IVS II -1 and IVS I -5 are the two common β gene mutations in Iran 5,7,8 . In a recent survey about different β globin gene mutations in Iran, other relatively prevalent mutations include frame shift (FS) mutations in codon 8/9 (+G), IVS I -110 (G>A), FSC 36/37 (-T), IVS I -I (G>A), IVS I (-25 bp), and codon 44 (-C) 5 . Various forms of β thalassemia result from single base substitution within the sequence of the IVS -I donor site. ...
Background : Thalassemia syndromes are the most prevalent hereditary hemoglobinopathies in the world. Iran is located on the thalassemia belt. In this study, the effect of Xmn -1 polymorphism and coinheritance of alpha mutations on age at first transfusion and also transfusion interval in Iranian thalassemic patients with homozygous IVSI-5 mutation were assessed.
Materials and Methods : In this retrospective cross-sectional study 154 transfusion dependent thalassemia (TDT) patients (140 patients with β-thalassemia major and 14 cases with β-thalassemia intermedia) who were homozygote of IVSI-5 mutation have been participated. Blood samples were collected from participants using EDTA containers for genomic DNA analysis. DNA extraction and amplification-refractory mutation to determine the Xmn -1 polymorphism were performed. Multiplex PCR was performed to identify alpha globin deletions.
Results: The mean age of participants was 29±7, 58 of them were male and 96 were female. A significant relation between presence of Xmn -1 polymorphism and age at receiving first transfusion was detected. Coinheritance of alpha thalassemia mutation does not have significant effect on age at first transfusion or transfusion interval.
Conclusion : Presence of Xmn -1 polymorphism can delay the onset of transfusion in patients with homozygote IVSI-5 mutation.
... In a study in mainland China by Lai et al, a meta-analysis of 16 articles (1981-2015) identified the CD41/42 mutation as the most common β-globin gene mutation while the most common mutation was HBβ: c.315+1 G>A in our study (13). According to the findings of Lama et al in Nepal (14) In their review article (2005-2014), Bazi and Miri-Moghaddam concluded that the IVS I-5 (G>C) and IVSII-1 (G>A) were introduced as the most common mutations (17). Likewise, Maryami et al demonstrated that IVSII-1 (G> A) and IVSI-5 were the most prevalent mutations among Iranian populations, respectively (1). ...
... Similar to the findings of previous studies (1,17,19,20), the results of our study revealed that the IVSII-1 mutation (G>A, namely, HBβ: c.315 + 1G>A) was the most common type in both females and males. Compared to the results of previous studies, the prevalence of the IVSI-5 (G>C) mutation (i.e., HBβ: c.92+ 5G>C) in our study was 6.4% and this mutation was not the most common mutation in Hamadan, which contradicts the findings of the abovementioned studies. ...
Background: β-Thalassemia (βT) is one of the most common genetic diseases. The specific mutation profile of that region can be identified by determining the specific mutations of each region and ethnicity.
Objectives: This study investigated the β-globin mutations in patients with βT in Hamadan.
Methods: This cross-sectional study was performed on 47 βT carriers. In the present study, the polymerase chain reaction (PCR)-sequencing technique was used to confirm βT carriers, and data were analyzed with SPSS-16 at a 95% confidence level.
Results: In general, 164 individuals (81 men and 83 women) suspected of having thalassemia were examined, where 28.7 % (n=47) of them were identified by PCR-sequencing with βT carriers (48.8% male and 53.2% females). Hemoglobin beta (HBβ): c.251 del, HBβ: c.27dupG, and HBβ: c.92+5G>A mutations had the greatest effect on mean corpuscular volume (MCV) reduction, mean corpuscular HB (MCH) reduction, and HbA2 increment, respectively. The most common mutation in both males and females was the same (HBβ: c.315+1G>A).
Conclusion: According to the results, the most common mutations in the diagnosis of βT in Hamadan were serially HBβ: c.315+1G>A mutation and HBβ: c.25-26del, HBβ: c.112del, HBβ: c.20A>T, HBβ: 92+6T>C, and HBβ: c.316-106C>G.
... Beta thalassemia disorder produced through a defect in beta globin chain and is one of the hemolytic anemia disorders.It is prevalent in Mediterraneancountries, Central Asia and Middle East 1 . Also, it is an important health problem in our country with frequency of 3-10% in some regions 2,3 . Spleen hyper-activation(hypersplenism) in beta thalassemia major causes massive destruction of red blood cells that increase need to recurrent blood transfusions 4 . ...
Aim: Natural immunity to Neisseria meningitides(NM) was evaluated in patients with beta thalassemia. Then, the proportion of natural protective immunity was compared between splenectomised and non splenectomised patients. Methodology: All patients with beta thalassemia major were enrolled in our descriptive study that was done in Thalassemia Ward of the academic hospital at Motahari Hospital, Jahrom, Iran. There was not any vaccination against Neisseria meningitides in Iranian National Vaccination schedule. All patients were categorized to groups A (non splenectomised) and B (splenectomised). Demographic data such as age and sex, and time after splenectomy (month) were recorded by a questionnaire. The levels of serum ferritin and serum anti meningococcalpolysaccharide capsule antigen IgGwere determined by enzyme-linked immune sorbent assay method. An IgG antibody level of 2µg/ml or higher was named as protective immunity (natural immunity) against N. meningitides. We used the independent student t, One-way ANOVA and chi square test to compare the means and ratios between study groups. For the data record and analysis, we used SPSS software version 16 (SPSS Inc., Chicago, IL, USA). A p-value less than 0.05 were considered as statistically significant. Results: Overall, 14.4% of patients had natural protective MN specific IgG antibody (≥ 2µg/ml). The trend of this protective immunity was insignificantly decreased with advancing age. Sex, post splenectomy duration and serum concentration of ferritin was no significant differences between immune and un-immune patients. The proportion of natural protective immunity was 17% and 11.7% in non splenectomised and splenectomised cases, respectively. Conclusions:Our results showed a lower natural protective immunity in patients with beta thalassemia major that it was similar in splenectomised and non splenectomised patients. Thus seems to be necessary that these susceptible patients vaccinate against NM.
