BCL11A Research Articles

Genetic analysis of a child with Dias-Logan syndrome due to variant of BCL11A gene

To analyze the clinical and genetic characteristics of a child featuring Dias-Logan syndrome. A child with speech disorders and delayed psychomotor development from childhood who was admitted to the Rehabilitation Medicine Department of Children's Hospital Affiliated to Zhengzhou University in July 2022 was selected as the research subject. Clinical data of the child was collected. Genomic DNA was extracted from peripheral blood samples of the child and his parents. Potential variant was screened by whole exome sequencing, and candidate variant was verified by Sanger sequencing. The child has presented with global developmental delay, microcephaly, special facial features and behavioral problems. Genetic testing revealed a de novo variant of the BCL11A gene, namely c.561_567delACACGCA (p.Q187fs*7), which was classified as pathogenic (PVS1+PS2+PM2_Supporting). The heterozygous variant of BCL11A gene probably underlay the Dias-Logan syndrome in this child. Above finding has enriched the phenotypic and mutational spectrum of the BCL11A gene and provides a basis for genetic counseling and clinical decision-making.

Genotyping the BCL11A Single Nucleotide Polymorphism and Associated Levels of Fetal Hemoglobin in Mauritanian Sickle Cell Patients.

Sickle cell disease (SCD) is a major heritable genetic disease in sub-Saharan Africa, including Mauritania. Fetal hemoglobin (HbF) can affect the pathophysiology, moderate the clinical course, and offer prospects for curative treatment of SCD. This study aimed to investigate the influence of single nucleotide polymorphisms (SNPs) in the BCL11A gene on the levels of HbF and hematological parameters in Mauritanian sickle cell (HbSS) patients. Complete blood count was assessed in 565 patients suspected to have SCD. Polymerase chain reaction (PCR)-restriction fragment length polymorphism was performed to identify the HbSS, and sequencing was used for genotyping three SNPs: rs4671393 (A>G) and rs11886868 (C>T) in the intron 2 and rs1052520 (G>A) in the 3'UTR regions of the BCL11A gene in 50 sickle cell patients. The prevalence of HbSS among the study population was 8.8% (50/565), and the mean (± standard deviation) of HbF level was 15.0% (± 6.0%). Sequencing showed the presence of three genotypes: AA (13.6%), AG (46.6%), GG (39.6%) in rs4671393; CC (17.6%), CT (48.7%), and TT (33.6%) in rs11886868. All samples from HbSS individuals displayed a wild-type genotype in the rs1052520 allele. The prevalence of minor alleles A (rs4671393) and C (rs11886868) were 37% and 39%, respectively. There was a statistically significant association (p = 0.034) between rs4671393 SNP and elevated HbF (mean 12.72 ± 6.26%). The study of three SNPs in the BCL11A locus in Mauritanian patients with SCD showed a significant association of rs4671393 allele with the HbF level. Further research is needed to explore additional SNPs in the BCL11A locus and investigate other genetic markers reported to modulate HbF levels, such as HBS1L-MYB and Xmn1-HBG2, to improve the management of this potentially life-threatening condition in Mauritania.

Pharmacogenomics of Drugs Used in β-Thalassemia and Sickle-Cell Disease: From Basic Research to Clinical Applications.

In this short review we have presented and discussed studies on pharmacogenomics (also termed pharmacogenetics) of the drugs employed in the treatment of β-thalassemia or Sickle-cell disease (SCD). This field of investigation is relevant, since it is expected to help clinicians select the appropriate drug and the correct dosage for each patient. We first discussed the search for DNA polymorphisms associated with a high expression of γ-globin genes and identified this using GWAS studies and CRISPR-based gene editing approaches. We then presented validated DNA polymorphisms associated with a high HbF production (including, but not limited to the HBG2 XmnI polymorphism and those related to the BCL11A, MYB, KLF-1, and LYAR genes). The expression of microRNAs involved in the regulation of γ-globin genes was also presented in the context of pharmacomiRNomics. Then, the pharmacogenomics of validated fetal hemoglobin inducers (hydroxyurea, butyrate and butyrate analogues, thalidomide, and sirolimus), of iron chelators, and of analgesics in the pain management of SCD patients were considered. Finally, we discuss current clinical trials, as well as international research networks focusing on clinical issues related to pharmacogenomics in hematological diseases.

Genetic Modifiers of Sickle Cell Anemia Phenotype in a Cohort of Angolan Children.

The aim of this study was to identify genetic markers in the HBB Cluster; HBS1L-MYB intergenic region; and BCL11A, KLF1, FOX3, and ZBTB7A genes associated with the heterogeneous phenotypes of Sickle Cell Anemia (SCA) using next-generation sequencing, as well as to assess their influence and prevalence in an Angolan population. Hematological, biochemical, and clinical data were considered to determine patients' severity phenotypes. Samples from 192 patients were sequenced, and 5,019,378 variants of high quality were registered. A catalog of candidate modifier genes that clustered in pathophysiological pathways important for SCA was generated, and candidate genes associated with increasing vaso-occlusive crises (VOC) and with lower fetal hemoglobin (HbF) were identified. These data support the polygenic view of the genetic architecture of SCA phenotypic variability. Two single nucleotide polymorphisms in the intronic region of 2q16.1, harboring the BCL11A gene, are genome-wide and significantly associated with decreasing HbF. A set of variants was identified to nominally be associated with increasing VOC and are potential genetic modifiers harboring phenotypic variation among patients. To the best of our knowledge, this is the first investigation of clinical variation in SCA in Angola using a well-customized and targeted sequencing approach.

Transcriptional Repressor BCL11A in Erythroid Cells.

BCL11A, a zinc finger repressor, is a stage-specific transcription factor that controls the switch from fetal (HbF, α2γ2) to adult (HbA, α2β2) hemoglobin in erythroid cells. While BCL11A was known as a factor critical for B-lymphoid cell development, its relationship to erythroid cells and HbF arose through genome-wide association studies (GWAS). Subsequent work validated its role as a silencer of γ-globin gene expression in cultured cells and mice. Erythroid-specific loss of BCL11A rescues the phenotype of engineered sickle cell disease (SCD) mice, thereby suggesting that downregulation of BCL11A expression might be beneficial in patients with SCD and β-thalassemia. Common genetic variation in GWAS resides in an erythroid-specific enhancer within the BCL11A gene that is required for its own expression. CRISPR/Cas9 gene editing of the enhancer revealed a GATA-binding site that confers a large portion of its regulatory function. Disruption of the GATA site leads to robust HbF reactivation. Advancement of a guide RNA targeting the GATA-binding site in clinical trials has recently led to approval of first-in-man use of ex vivo CRISPR editing of hematopoietic stem/progenitor cells (HSPCs) as therapy of SCD and β-thalassemia. Future challenges include expanding access and infrastructure for delivery of genetic therapy to eligible patients, reducing potential toxicity and costs, exploring prospects for in vivo targeting of hematopoietic stem cells (HSCs), and developing small molecule drugs that impair function of BCL11A protein as an alternative option.

Therapeutic approaches for sickle cell disease by targeting BCL11A

Sickle cell disease (SCD) is one of the most serious diseases in the world caused by gene mutat ions. People with SCD have sickle-shaped red blood cells. BCL11A can inhibit the formation of γ-protein which can lead to the reduction of HbF,the reduction of the ability of hemoglobin to carry oxygen. Thus, d ecreasing the quantity of BCL11A can be a potential target to treat SCD.One of the potentially effective tr eatment approaches is to edit BCL11A genes with CRISPR technology.CRISPR is a gene-editing technolo gy,which can precisely and efficiently locate the treatment targets.With CRISPR technology,the gene expr ession of BCL11A can be blocked,and γ-protein can be switched to form more HbF.Hemoglobin levels for transporting oxygen can return to normal.This review introduces and summarizes the mechanisms to treat SCD andtheir limitations.Previous research papers revealed that the treatments of SCD are one-dimension al and these treatments just can inhibit disease.Fundamental problems of SCD remain to be solved.

Efficacy and Safety of Brl-101, CRISPR-Cas9-Mediated Gene Editing of the BCL11A Enhancer in Transfusion-Dependent β-Thalassemia

BACKGROUND: β-Thalassemia is an inherited hemolytic disease that is prevalent worldwide. Over 200 mutations in the HBB gene, which encodes adult hemoglobin (HbA), result in β-thalassemia. Hereditary persistence of fetal hemoglobin (HbF) can alleviate the symptoms of anemia. CRISPR-Cas9-mediated disruption of the BCL11A erythroid enhancer results in the reduction of BCL11A expression and the induction of fetal γ-globin, which is a practicable therapeutic strategy for treating transfusion-dependent β-thalassemia (TDT). METHODS: We obtained mobilized autologous CD34+ cells from 4 TDT patients sponsor initiated in phase I/II clinical trial (NCT05577312) and 6 TDT patients in investigator initiated clinical study（NCT04211480, NCT04205435）respectively. These cells were edited with CRISPR-Cas9 RNP at the +58 erythroid specific enhancer region of the BCL11A gene and then reinfused after the patients had undergone myeloablative busulfan conditioning. We subsequently monitored adverse events, neutrophil and platelet engraftment. Efficacy assessments included proportion of transfusion-independent (TI) subjects, levels of total hemoglobin and HbF, and proportion of red blood cells expressing HbF in peripheral blood. TI was evaluated for elimination of transfusions starting 42 days after the last transfusion and Hb above 90 g/L. RESULTS: Between October 15, 2019 and November 20, 2022, 10 patients with TDT were enrolled and received BRL-101 with a median age of 12.4 years (6-26). Among all the treated patients, 5 patients were β 0/β 0 phenotype, 4 patients were β0/β+ phenotype and 1 patient were β +/β + phenotype. As of July 20, 2023, the median follow- up was 24.6 months (4.3-39.2 m) (Tab.1). All of 10 patients achieved TI. The median duration of TI was 22.1 months (1.3 - 37.2 m). The longest duration of TI was 37.2 months (Fig.1). The levels of HbF ranged from 2.3 to 140.7g/L and the levels of total hemoglobin ranged from 105.7 to 149 g/L (Fig.2). At 6 months after BRL-101 infusion, the proportion of HbF-expressing red blood cells in peripheral blood had reached 96.5%, and then continued to rise and remained around 98-99% (Fig.3). Treatment-related adverse events were typical of those associated with myeloablation and autologous stem-cell transplantation, mainly manifested as hematological toxicities (Tab.2, Tab.3). 3 patients experienced adverse events (AEs) grade ≥ 3 which related to BRL-101. 4 patients experienced serious AEs (SAEs), including decreased platelet count, shock, febrile infection, soft tissue infection, and veno-occlusive liver disease. Only decreased platelet count may related to BRL-101, the others were due to busulfan treatment. All the SAEs were resolved. No study drug-related withdrawals or deaths occurred during treatment. CONCLUSIONS: Whether genotype was β 0/β 0 or non-β 0/β 0, BRL-101 demonstrated clinically meaningful increases in total Hb and HbF which occurred early and have been maintained over time, the safety profile of BRL-101 is generally consistent with that of myeloablative conditioning and autologous hematopoietic stem cell transplant. The updated data with 10 patients reported here are consistent with previous reports and support continued investigation of BRL-101 as a potential functional cure for patients with TDT.

Exagamglogene Autotemcel for Severe Sickle Cell Disease

Background: Exagamglogene autotemcel (exa-cel) is a non-viral cell therapy designed to reactivate fetal hemoglobin via ex vivo CRISPR-Cas9 gene-editing of autologous CD34+ hematopoietic stem and progenitor cells (HSPCs) at the erythroid-specific enhancer region of the BCL11A gene in patients (pts) with severe sickle cell disease (SCD). We report that in a pre-specified interim analysis, the pivotal CLIMB SCD-121 trial of exa-cel met primary and key secondary endpoints. Methods: CLIMB SCD-121 is an ongoing, 24-mo, phase 3 trial of exa-cel in pts age 12-35y with SCD and a history of ≥2 VOCs/y in 2y prior to screening. Primary efficacy endpoint is proportion of pts free of severe VOCs for ≥12 consecutive months (mos) (VF12); key secondary efficacy endpoints are proportion of pts free from inpatient hospitalization for severe VOCs for ≥12 consecutive mos (HF12) and proportion of pts free from severe VOCs for ≥9 consecutive mos (VF9). Evaluable pts for VF12 and HF12 had ≥16 mos follow-up after exa-cel infusion; pts evaluable for VF9 had ≥12 mos follow-up after infusion. Evaluation of primary and key secondary endpoints began 60 days after last RBC transfusion for post-transplant support or SCD management. Pts completing trial enrolled in long-term follow-up Study 131. Mean (SD) are shown except where noted. Results: As of 10 Feb 2023, 42 pts with SCD (age 21.2[range 12-34]y; 12[28.6%] age ≥12 to <18y; 4.2 VOCs/y at baseline) received exa-cel. Following infusion, all pts engrafted neutrophils and platelets (median 27 and 34.5 days, respectively). 19/20 (95.0%) pts evaluable for primary endpoint were free of VOCs for ≥12 consecutive mos (VF12; 95% CI, 75.1% to 99.9%; P<0.0001), 20/20 (100%) were free from hospitalizations for VOCs for ≥12 consecutive mos (HF12; 95% CI, 83.2 to 100.0; P<0.0001), and 29/30 (96.7%) were free of VOCs for ≥9 consecutive mos (VF9; 95% CI, 82.8 to 99.9; P<0.0001). In pts achieving VF12, VOC free duration was 21.8 (range 12.3-41.4) mos; 18 pts remained VOC free through follow-up and 1 pt had an adjudicated VOC in the setting of parvovirus infection ~22.8 mos after exa-cel; pt recovered fully and has since been VOC free (Fig). For all pts, total Hb was 12.1 g/dL at Month 3 and was maintained at ≥11.0 g/dL from Month 6 onward; HbF was 36.0% at Month 3 and was generally maintained at ≥ 40.0% from Month 6 onward with pancellular distribution (≥95% RBCs expressing HbF). Proportion of edited BCL11A alleles was stable over time in bone marrow CD34 + and peripheral blood nucleated cells. 36/39 pts with ≥60 days follow-up after last RBC transfusion (including those not yet evaluable) remained VOC free (up to 41.4 mos; Fig). Quality-of-life (QOL) measures showed clinically significant improvements from baseline. All pts had ≥1 adverse event (AE), most were Grade 1 or 2; 40 (95.2%) pts had AEs of Grade 3 or 4 severity. Most common AEs were nausea (66.7%), stomatitis (61.9%), febrile neutropenia (52.4%), headache (52.4%), and vomiting (52.4%). Most AEs and serious AEs (SAEs) occurred within first 6 mos after infusion. No pts had SAEs considered related to exa-cel. As previously reported, 1 pt died from respiratory failure due to COVID-19 unrelated to exa-cel. There were no study discontinuations or malignancies. Conclusions: The CLIMB SCD-121 trial met primary and key secondary endpoints, with exa-cel treatment resulting in early and sustained increases in Hb and HbF leading to elimination of VOCs in 95% of pts, elimination of inpatient hospitalization for VOCs in 100% of pts and improved QOL. Safety profile of exa-cel was generally consistent with myeloablative busulfan conditioning and autologous transplantation. These results show exa-cel has the potential to deliver a one-time functional cure to pts with severe SCD.

Effects of Mithramycin on BCL11A Gene Expression and on the Interaction of the BCL11A Transcriptional Complex to γ-Globin Gene Promoter Sequences.

The anticancer drug mithramycin (MTH), has been proposed for drug repurposing after the finding that it is a potent inducer of fetal hemoglobin (HbF) production in erythroid precursor cells (ErPCs) from β-thalassemia patients. In this respect, previously published studies indicate that MTH is very active in inducing increased expression of γ-globin genes in erythroid cells. This is clinically relevant, as it is firmly established that HbF induction is a valuable approach for the therapy of β-thalassemia and for ameliorating the clinical parameters of sickle-cell disease (SCD). Therefore, the identification of MTH biochemical/molecular targets is of great interest. This study is inspired by recent robust evidence indicating that the expression of γ-globin genes is controlled in adult erythroid cells by different transcriptional repressors, including Oct4, MYB, BCL11A, Sp1, KLF3 and others. Among these, BCL11A is very important. In the present paper we report evidence indicating that alterations of BCL11A gene expression and biological functions occur during MTH-mediated erythroid differentiation. Our study demonstrates that one of the mechanisms of action of MTH is a down-regulation of the transcription of the BCL11A gene, while a second mechanism of action is the inhibition of the molecular interactions between the BCL11A complex and specific sequences of the γ-globin gene promoter.

Responses of β-thalassemia and compound heterozygote of Sickle/βthalassemia of BCL11A Gene Polymorphism in Pakistani Patients.

Beta-thalassemia major (β-Thal) and compound heterozygote of Sickle β-thalassemia (S-β Thal) are hereditary autosomal recessive disorders resulting from mutations or deletion in β-globin gene cluster. Patients with increased HbF levels having polymorphism at BCL11A site loci have shown clinical significance. The present study aimed to assess the frequency of BCL11A gene polymorphism in a study population of β-Thal, S-β Thal & Controls using Sanger sequencing leading to plot the HbF response of polymorphism with reference to wild type. The sample size of the study is n=180, groups were divided in Controls, β-thal & S-β thal. One ml blood was drawn from patients and controls to extract DNA for PCR amplification and BCL11A locus genotyping using Sanger sequencing. This study was carried out at Dow Research Institute of Biotechnology and Biomedical Sciences, for one year from March 2021 to February 2022. The HbF response of three groups is hyperbolic with 83 for β-Thal, 16 for S-β Thal and close to zero for controls. The frequency of heterozygous variant GA of BCL11A gene polymorphism is 51%. The frequency of homozygous variant GG is 49%. Complete absence of wild type AA in patient group. The frequency of BCL11A polymorphism in control group was 43% (with male 18% and female 21%) showing wild type status of 57%. The patient groups of SCD and Beta thalassemia are devoid of wild type status. The wild type status of BCL11A is 57% even in control population. Higher level of HbF in B-thalassemia and SCD and B Thalassemia is a cost-effective screening marker before switching to an expensive genotyping testing.

Exploration of Key Immune-Related Transcriptomes Associated with Doxorubicin-Induced Cardiotoxicity in Patients with Breast Cancer

Based on a few studies, heart failure patients with breast cancer were assessed to find potential biomarkers for doxorubicin-induced cardiotoxicity. However, key immune-related transcriptional markers linked to doxorubicin-induced cardiotoxicity in breast cancer patients have not been thoroughly investigated. We used GSE40447, GSE76314, and TCGA BRCA cohorts to perform this study. Then, we performed various bioinformatics approaches to identify the key immune-related transcriptional markers and their association with doxorubicin-induced cardiotoxicity in patients with breast cancer. We found 255 upregulated genes and 286 downregulated genes in patients with doxorubicin-induced heart failure in breast cancer. We discovered that in patients with breast cancer comorbidity doxorubicin-induced cardiotoxicity, the 58 immunological genes are elevated (such as CPA3, VSIG4, GATA2, RFX2, IL3RA, and LRP1), and the 60 genes are significantly suppressed (such as MS4A1, FCRL1, CD200, FCRLA, FCRL2, and CD79A). Furthermore, we revealed that the immune-related differentially expressed genes (DEGs) are substantially associated with the enrichment of KEGG pathways, including B-cell receptor signaling pathway, primary immunodeficiency, chemokine signaling pathway, hematopoietic cell lineage, cytokine-cytokine receptor interaction, Toll-like receptor signaling pathway, MAPK signaling pathway, focal adhesion, dilated cardiomyopathy, cell adhesion molecule, etc. Moreover, we discovered that the doxorubicin-induced immune-related genes are crucially involved in the protein–protein interaction and gene clusters. The immune-related genes, including IFIT5, XCL1, SPIB, BTLA, MS4A1, CD19, TCL1A, CD83, CD200, FCRLA, CD79A, BIRC3, and IGF2R are significantly associated with a poor survival prognosis of breast cancer patients and showed diagnostic efficacy in patients with breast cancer and heart failure. Molecular docking revealed that the survival-associated genes interact with the doxorubicin with appreciable binding affinity. Finally, we validated the expression level of immune-related genes in breast cancer patients-derived cardiomyocytes with doxorubicin-induced cardiotoxicity and found that the level of RAD9A, HSPA1B, GATA2, IGF2R, CD200, ERCC8, and BCL11A genes are consistently dysregulated. Our findings offered a basis for understanding the mechanism and pathogenesis of the cardiotoxicity caused by doxorubicin in breast cancer patients and predicted the interaction of immune-related potential biomarkers with doxorubicin.

CRISPR gene technology—the next best thing in medicine

CRISPR gene technology—the next best thing in medicine

Recombinant Cas9 protein production in an endotoxin-free system and evaluation with editing the BCL11A gene in human cells

Many therapeutic proteins are expressed in Escherichia coli bacteria for the low cost and high yield obtained. However, these gram-negative bacteria also generate undesirable endotoxin byproducts such as lipopolysaccharides (LPS). These endotoxins can induce a human immune response and cause severe inflammation. To mitigate this problem, we have employed the ClearColi BL21 (DE3) endotoxin-free cells as an expression host for Cas9 protein production. Cas9 is an endonuclease enzyme that plays a key role in the Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and CRISPR associated protein 9 (CRISPR/Cas9) genome editing technique. This technology is very promising for use in diagnostics as well as treatment of diseases, especially for genetic diseases such as thalassemia. The potential uses for this technology thus generate a considerable interest for Cas9 utilization as a therapeutic protein in clinical treatment. Therefore, special care in protein production should be a major concern. Accordingly, we expressed the Cas9 protein in endotoxin-free bacterial cells achieving 99% purity with activity comparable to commercially available Cas9. Our protocol therefore yields a cost-effective product suitable for invitro experiments with stem cells.

Identification of two unannotated miRNAs in classic Hodgkin lymphoma cell lines.

MicroRNAs (miRNAs) are small non coding RNAs responsible for posttranscriptional regulation of gene expression. Even though almost 2000 precursors have been described so far, additional miRNAs are still being discovered in normal as well as malignant cells. Alike protein coding genes, miRNAs may acquire oncogenic properties in consequence of altered expression or presence of gain or loss of function mutations. In this study we mined datasets from miRNA expression profiling (miRNA-seq) of 7 classic Hodgkin Lymphoma (cHL) cell lines, 10 non-Hodgkin lymphoma (NHL) cell lines and 56 samples of germinal center derived B-cell lymphomas. Our aim was to discover potential novel cHL oncomiRs not reported in miRBase (release 22.1) and expressed in cHL cell lines but no other B-cell lymphomas. We identified six such miRNA candidates in cHL cell lines and verified the expression of two of them encoded at chr2:212678788-212678849 and chr5:168090507-168090561 (GRCh38). Interestingly, we showed that one of the validated miRNAs (located in an intron of the TENM2 gene) is expressed together with its host gene. TENM2 is characterized by hypomethylation and open chromatin around its TSS in cHL cell lines in contrast to NHL cell lines and germinal centre B-cells respectively. It indicates an epigenetic mechanism responsible for aberrant expression of both, the TENM2 gene and the novel miRNA in cHL cell lines. Despite the GO analysis performed with the input of the in silico predicted novel miRNA target genes did not reveal ontologies typically associated with cHL pathogenesis, it pointed to several interesting candidates involved in i.e. lymphopoiesis. These include the lymphoma related BCL11A gene, the IKZF2 gene involved in lymphocyte development or the transcription initiator GTF2H1.

Novel lentiviral vectors for gene therapy of sickle cell disease combining gene addition and gene silencing strategies

Sickle cell disease (SCD) is due to a mutation in the β-globin gene causing production of the toxic sickle hemoglobin (HbS; α2βS 2). Transplantation of autologous hematopoietic stem and progenitor cells (HSPCs) transduced with lentiviral vectors (LVs) expressing an anti-sickling β-globin (βAS) is a promising treatment; however, it is only partially effective, and patients still present elevated HbS levels. Here, we developed a bifunctional LV expressing βAS3-globin and an artificial microRNA (amiRNA) specifically downregulating βS-globin expression with the aim of reducing HbS levels and favoring βAS3 incorporation into Hb tetramers. Efficient transduction of SCD HSPCs by the bifunctional LV led to a substantial decrease of βS-globin transcripts in HSPC-derived erythroid cells, a significant reduction of HbS+ red cells, and effective correction of thesickling phenotype, outperforming βAS gene addition and BCL11A gene silencing strategies. The bifunctional LV showed a standard integration profile, and neither HSPC viability, engraftment, and multilineage differentiation nor the erythroid transcriptome and miRNAome were affected by the treatment, confirming the safety of this therapeutic strategy. In conclusion, the combination of gene addition and gene silencing strategies can improve the efficacy of current LV-based therapeutic approaches without increasing the mutagenic vector load, thus representing a novel treatment for SCD.

Impact of Genetic Polymorphisms in Modifier Genes in Determining Fetal Hemoglobin Levels in Beta-Thalassemia

Genetic polymorphisms in Quantitative Trait Loci (QTL) genes such as BCL11A, HBS1L-MYB and KLF1 have been reported to influence fetal hemoglobin (HbF) levels. This prospective study was planned to evaluate the role of genetic polymorphisms in QTL genes as determinant of HbF levels in beta thalassemia major patients. The study was carried out on 100 thalassemia major patients. Blood samples were collected in EDTA and plain vials for biochemical and molecular evaluation. The BCL11A, HBS1L-MYB and KLF1 genotypes were determined using a polymerase chain reaction (PCR)-based method. Red Blood Cell (RBC) indices and HbF levels were assessed. In silico analysis was assessed using loss-of-function tool (Lof Tool). Statistical difference and genetic comparisons between groups were evaluated by using SPSS for Windows, version 16.0 (SPSS Inc., Chicago, IL, USA). Comparisons between quantitative variables were carried out after data explored for normality using Kolmogorov–Smirnov test of normality. Logistic regression was used for computation of ORs and 95% CIs (Confidence Interval). We observed association of HbF levels in thalassemia major patients with the polymorphisms in BCL11A (rs11886868 rs7557939; rs1427407 and rs766432) and HBS1L-MYB (rs9399137) gene. The results of this study indicated that the presence of polymorphisms on modifier genes are strongly associated with an increase in HbF levels in thalassemia major patients. Further research with a larger sample size and with other genes of modifier genes is required.

Trait − driven analysis of the 2p15p16.1 microdeletion syndrome suggests a complex pattern of interactions between candidate genes

BackgroundIndividuals with the 2p15p16.1 microdeletion syndrome share a complex phenotype including neurodevelopmental delay, brain malformations, microcephaly, and autistic behavior. The analysis of the shortest region of overlap (SRO) between deletions in ~ 40 patients has led to the identification of two critical regions and four strongly candidate genes (BCL11A, REL, USP34 and XPO1). However, the delineation of their role in the occurrence of specific traits is hampered by their incomplete penetrance.ObjectiveTo better delineate the role of hemizygosity of specific regions in selected traits by leveraging information both from penetrant and non − penetrant deletions.MethodsDeletions in patients that do not present a specific trait cannot contribute to delineate the SROs. We recently developed a probabilistic model that, by considering also the non − penetrant deletions, allows a more reliable assignment of peculiar traits to specific genomic segments. We apply this method adding two new patients to the published cases.ResultsOur results delineate an intricate pattern of genotype − phenotype correlation where BCL11A emerges as the main gene for autistic behavior while USP34 and/or XPO1 haploinsufficiency are mainly associated with microcephaly, hearing loss and IUGR. BCL11A, USP34 and XPO1 genes are broadly related with brain malformations albeit with distinct patterns of brain damage.ConclusionsThe observed penetrance of deletions encompassing different SROs and that predicted when considering each single SRO as acting independently, may reflect a more complex model than the additive one. Our approach may improve the genotype/phenotype correlation and may help to identify specific pathogenic mechanisms in contiguous gene syndromes.

A Review of CRISPR Cas9 for SCA: Treatment Strategies and Could Target β-globin Gene and BCL11A Gene using CRISPR Cas9 Prevent the Patient from Sickle Cell Anemia?

BACKGROUND: Sickle cell anemia is a hereditary globin chain condition that leads to hemolysis and persistent organ damage. Chronic hemolytic anemia, severe acute and chronic pain, and end-organ destruction occur throughout the lifespan of sickle cell anemia. SCD is associated with a higher risk of mortality. Genome editing with CRISPR-associated regularly interspersed short palindromic repeats (CRISPR/Cas9) have therapeutic potential for sickle cell anemia thala. AIM: This research aimed to see if using CRISPR/Cas9 to target β-globin gene is an effective therapeutic and if it has a long-term effect on Sickle Cell Anemia. METHODS: The method used in this study summarizes the article by looking for keywords that have been determined in the title and abstract. The authors used official guidelines from Science Direct, PubMed, Google Scholar, and Journal Molecular Biology to select full-text articles published within the last decade, prioritizing searches within the past 10 years. RESULTS: CRISPR/Cas9-mediated genome editing in clinical trials contributes to α-globin gene deletion correcting β-thalassemia through balanced α- and β-globin ratios and inhibiting disease progression. CONCLUSION: HBB and BCL11A targeting by CRISPR/Cas9 deletion effectively inactivate BCL11A, a repressor of fetal hemoglobin production. However, further research is needed to determine its side effects and safety.

Automated Good Manufacturing Practice-Compatible CRISPR-Cas9 Editing of Hematopoietic Stem and Progenitor Cells for Clinical Treatment of β-Hemoglobinopathies.

Cellular therapies hold enormous potential for the cure of severe hematological and oncological disorders. The forefront of innovative gene therapy approaches including therapeutic gene editing and hematopoietic stem cell transplantation needs to be processed by good manufacturing practice to ensure safe application in patients. In the present study, an effective transfection protocol for automated clinical-scale production of genetically modified hematopoietic stem and progenitor cells (HSPCs) using the CliniMACS Prodigy® system including the CliniMACS Electroporator (Miltenyi Biotec) was established. As a proof-of-concept, the enhancer of the BCL11A gene, clustered regularly interspaced short palindromic repeat (CRISPR) target in ongoing clinical trials for β-thalassemia and sickle-cell disease treatment, was disrupted by the CRISPR-Cas9 system simulating a large-scale clinical scenario, yielding 100 million HSPCs with high editing efficiency. In vitro erythroid differentiation and high-performance liquid chromatography analyses corroborated fetal hemoglobin resurgence in edited samples, supporting the feasibility of running the complete process of HSPC gene editing in an automated closed system.

Genetic analysis of a family with BCL11A-related intellectual disability

To explore the genetic basis for two patients from a family with BCL11A-related intellectual disability (BCL11A-ID). Clinical data of the proband and her family members was analyzed. Chromosomal karyotyping analysis, trio-whole exome sequencing (trio-WES) and copy number variation sequencing (CNV-seq) were carried out. For the suspected genetic variants, Sanger sequencing was used to verify, and pathogenicity assessment was conducted. The proband and her mother both had intellectual and language impairment, and their fetal hemoglobin (HbF) was significantly elevated. A heterozygous c.1327_c.1328delTC (p.Ser443Hisfs*128) variant was found in exon 4 of the BCL11A gene by WES, which has resulted in truncated expression of the encoded protein, and Sanger sequencing has verified that the variant was inherited from the mother. The variant was not found in related databases. The variant was predicted as pathogenic according to the guidelines from the American College of Medical Genetics and Genomics (ACMG) (PVS1+PM2+PP1). No karyotypic abnormality was found in the proband, her parents and brother, and no pathogenic CNVs was found in the proband and her parents. The c.1327_c.1328delTC (p.Ser443Hisfs*128) variant may underlay the BCL11A-ID in the proband and her mother. This de novo variant has expanded the mutational spectrum of the BCL11A gene.