Context base editing for splice correction of IVSI-110 β-thalassemia.

β-Thalassemia is brought about by defective β-globin (HBB [hemoglobin subunit β]) formation and, in severe cases, requires regular blood transfusion and iron chelation for survival. Genome editing of hematopoietic stem cells allows correction of underlying mutations as curative therapy. As potentially safer alternatives to double-strand-break-based editors, base editors (BEs) catalyze base transitions for precision editing of DNA target sites, prompting us to reclone and evaluate two recently published adenine BEs (ABEs; SpRY and SpG) with relaxed protospacer adjacent motif requirements for their ability to correct the common splice mutation.

Unravelling the Complexity of the +33 C>G [HBB:c.-18C>G] Variant in Beta Thalassemia.

The +33 C>G variant [NM_000518.5(HBB):c.-18C>G] in the 5' untranslated region (UTR) of the β-globin gene is described in the literature as both mild and silent, while it causes a phenotype of thalassemia intermedia in the presence of a severe β-thalassemia allele.

Evaluation of Mono- and Bi-Functional GLOBE-Based Vectors for Therapy of β-Thalassemia by Gene Addition and Mutation-Specific RNA Interference.

Therapy via the gene addition of the anti-sickling β-globin transgene is potentially curative for all β-hemoglobinopathies and therefore of particular clinical and commercial interest. This study investigates GLOBE-based lentiviral vectors (LVs) for β-globin addition and evaluates strategies for an increased β-like globin expression without vector dose escalation. First, we report the development of a GLOBE-derived LV, GLV2-βAS3, which, compared to its parental vector, adds anti-sickling action and a transcription-enhancing 848-bp transcription terminator element, retains high vector titers and allows for superior β-like globin expression in primary patient-derived hematopoietic stem and progenitor cells (HSPCs).

A Multicenter ICET-A Study on Age at Menarche and Menstrual Cycles in Patients with Transfusion-Dependent Thalassemia (TDT) who Started Early Chelation Therapy with Different Chelating Agents.

Introduction: To evaluate the effect of early chelation therapy (≤ 3 years) with a variety of chelating agents on age at menarche and menstrual characteristics in patients with transfusion-dependent thalassemia (TDT).

Design: A retrospective multicenter study promoted by the International Network of Clinicians for Endocrinopathies in Thalassemia and Adolescent Medicine (ICET-A).

Setting: Eight of 13 International Thalassemia Centers (61.

High-efficiency editing in hematopoietic stem cells and the HUDEP-2 cell line based on mRNA synthesis.

Genome editing tools, such as CRISPR/Cas, TALE nucleases and, more recently, double-strand-break-independent editors, have been successfully used for gene therapy and reverse genetics. Among various challenges in the field, tolerable and efficient delivery of editors to target cells and sites, as well as independence from commercially available tools for flexibility and fast adoption of new editing technology are the most pressing. For many hematopoietic research applications, primary CD34 cells and the human umbilical cord-derived progenitor erythroid 2 (HUDEP-2) cell line are highly informative substrates and readily accessible for manipulation.

A Retrospective Long-Term Study on Age at Menarche and Menstrual Characteristics in 85 Young Women with Transfusion-Dependent β-Thalassemia (TDT).

Background: Menarche is an important milestone in a feminine reproductive life, and regular menstrual cycles reflect normal functioning of the hypothalamic-pituitary-ovarian axis, a vital sign of women's general health.

Aim Of The Study: We explored the age at menarche and the following menstrual cycles characteristics among 85 unmarried Transfusion-Dependent β-Thalassemia (TDT) women, born between 1965 and 1995, concerning iron chelation therapy (ICT) with desferrioxamine (DFO) and nutritional status, assessed by body mass index (BMI).

Results: 53 adolescents who had begun ICT before the age of 10 years experienced menarche at 13,7 ± 1,6 years (mean ± DS), whereas 32 who began treatment after ten years experienced menarche significantly later (15.

A comprehensive update of ICET-A Network on COVID-19 in thalassemias: what we know and where we stand.

A review of the literature on COVID-19 pandemic in patients with thalassemias is presented. Globally, the prevalence of COVID-19 among  β-thalassemia patients seems to be lower than in general population; associated co-morbidities aggravated the severity of  COVID- 19, leading to a poorer prognosis, irrespective of age. A multicenter registry will enhance the understanding of COVID-19 in these patients and will lead to more evidence-based management recommendations.

Effect of HBB genotype on survival in a cohort of transfusion-dependent thalassemia patients in Cyprus.

Initiation of regular transfusion in transfusion-dependent thalassemia (TDT) is based on the assessment of clinical phenotype. Pathogenic HBB variants causing β-thalassemia are important determinants of phenotype and could be used to aid decision making. We investigated the association of HBB genotype with survival in a cohort study in the four thalassemia centres in Cyprus.

Preliminary Data on COVID-19 in Patients with Hemoglobinopathies: A Multicentre ICET-A Study.

Objectives: This study aims to investigate, retrospectively, the epidemiological and clinical characteristics, laboratory results, radiologic findings, and outcomes of COVID-19 in patients with transfusion-dependent β thalassemia major (TM), β-thalassemia intermedia (TI) and sickle cell disease (SCD).

Design: A total of 17 Centers, from 10 countries, following 9,499 patients with hemoglobinopathies, participated in the survey.

Main Outcome Data: Clinical, laboratory, and radiologic findings and outcomes of patients with COVID-19 were collected from medical records and summarized.

Evaluation of the efficacy and safety of deferiprone compared with deferasirox in paediatric patients with transfusion-dependent haemoglobinopathies (DEEP-2): a multicentre, randomised, open-label, non-inferiority, phase 3 trial.

Background: Transfusion-dependent haemoglobinopathies require lifelong iron chelation therapy with one of the three iron chelators (deferiprone, deferasirox, or deferoxamine). Deferasirox and deferiprone are the only two oral chelators used in adult patients with transfusion-dependent haemoglobinopathies. To our knowledge, there are no randomised clinical trials comparing deferiprone, a less expensive iron chelator, with deferasirox in paediatric patients.

2'-O-methoxyethyl splice-switching oligos correct splicing from IVS2-745 β-thalassemia patient cells restoring HbA production and chain rebalance.

β-thalassemia is a disorder caused by altered hemoglobin protein synthesis and affects individuals worldwide. Severe forms of the disease, left untreated, can result in death before the age of 3 years (1). The standard of care consists of chronic and costly palliative treatment by blood transfusion combined with iron chelation.

A Concise Review on the Frequency, Major Risk Factors and Surveillance of Hepatocellular Carcinoma (HCC) in β-Thalassemias: Past, Present and Future Perspectives and the ICET-A Experience.

Due to the recent alarming increase in the incidence of hepatocellular carcinoma (HCC) in thalassemias, the present report reviews briefly the frequency, the major risk factors, and the surveillance of HCC in β-thalassemias. Over the past 33 years, 153 cases of HCC were reported in patients with thalassemia, mainly in Italy and Greece. Among HCV-infected patients, additional factors promoting the development of HCC included: advanced age, male sex, chronic hepatitis B (CHB) co-infection, and iron overload.

Evaluation of endocrine complications in beta-thalassemia intermedia (β-TI): a cross-sectional multicenter study.

Background: Data on the prevalence and type of endocrine disorders in β-thalassemia intermedia (β-TI) patients are scarce. This multicenter study was designed to determine the prevalence of endocrine complications and the associated risk factors in a large group of β-TI patients.

Methods: In this cross-sectional multicenter study, 726 β-TI patients, aged 2.

The Scope for Thalassemia Gene Therapy by Disruption of Aberrant Regulatory Elements.

The common IVSI-110 (G>A) β-thalassemia mutation is a paradigm for intronic disease-causing mutations and their functional repair by non-homologous end joining-mediated disruption. Such mutation-specific repair by disruption of aberrant regulatory elements (DARE) is highly efficient, but to date, no systematic analysis has been performed to evaluate disease-causing mutations as therapeutic targets. Here, DARE was performed in highly characterized erythroid IVSI-110(G>A) transgenic cells and the disruption events were compared with published observations in primary CD34 cells.

Marital status and paternity in patients with Transfusion- Dependent Thalassemia (TDT) and Non Transfusion-Dependent Thalassemia (NTDT): an ICET - A survey in different countries.

Background: More than five decades ago, thalassemia major (TDT) was fatal in the first decade of life. Survival and quality of life have improved progressively thanks to the implementation of a significant advance in diagnostic and therapeutic methods, consisting mainly of a frequent transfusion program combined with intensive chelation therapy. Improvement also includes imaging methods used to measure liver and cardiac iron overload.

A novel mutation in the erythroid transcription factor KLF1 is likely responsible for ameliorating β-thalassemia major.

We describe the identification of a novel missense mutation in the second zinc finger of KLF1 in two siblings who, based on their genotype, are predicted to suffer from beta thalassemia major but are, in fact, transfusion-free and in good health. These individuals, as well as two additional members of the same family also carrying this KLF1 mutation, exhibit high levels of fetal hemoglobin (HbF). KLF1 is an erythroid transcription factor, which plays a critical role in the regulation of the developmental switch between fetal and adult hemoglobin by regulating the expression of a multitude of genes including that of BCL11A.

An ICET-A survey on occult and emerging endocrine complications in patients with β-thalassemia major: Conclusions and recommendations.

In adult thalassemia major (TM) patients, a number of occult and emerging endocrine complications, such as: central hypothyroidism (CH), thyroid cancer, latent hypocortisolism, and growth hormone deficiency (GHD) have emerged and been reported. As the early detection of these complications is essential for appropriate treatment and follow-up, the International Network of Clinicians for Endocrinopathies in Thalassemia and Adolescent Medicine (ICET-A) promoted a survey on these complications in adult TM patients, among physicians (pediatricians, hematologists and endocrinologists) caring for TM patients in different countries. The data reported by 15 countries are presented.

An ICET- A survey on Hypoparathyroidism in Patients with Thalassaemia Major and Intermedia: A preliminary report.

Hypoparathyroidism (HPT) is a rare disease with leading symptoms of hypocalcemia, associated with high serum phosphorus levels and absent or inappropriately low levels of parathyroid hormone (PTH). In patients with thalassemias it is mainly attributed to transfusional iron overload, and suboptimal iron chelation therapy. The main objectives of this survey were to provide data on the prevalence, demographic and clinical features of HPT in thalassemia major (TM) and intermedia (TI) patients living in different countries, and to assess its impact in clinical medical practice.

First study on iron complexes in blood and organ samples from thalassaemic and normal laboratory mice using Mössbauer spectroscopy.

Measurements of iron complexes and iron stores in the body are crucial for evaluation and management of chelation therapy targeted against iron accumulation or overload in blood and organs. In this work, blood and tissue samples from one normal and one thalassaemic laboratory mouse were studied using Fe Mössbauer spectroscopy at 78 K for the first time. In contrast to human patients, these laboratory mice did not receive any medical treatment, thus the iron components present in the samples are not altered from their natural state.

Review and Recommendations on Management of Adult Female Thalassemia Patients with Hypogonadism based on Literature Review and Experience of ICET-A Network Specialists.

Background: Multi-transfused thalassemia major (TM) patients frequently develop severe endocrine complications, mainly due to iron overload, anemia, and chronic liver disease, which require prompt diagnosis, treatment and follow-up by specialists. The most common endocrine complication documented is hypogonadotropic hypogonadism which increases with age and associated comorbidities. It is thus important for physicians to have a clear understanding of the pathophysiology and management of this disorder.

The molecular spectrum and distribution of haemoglobinopathies in Cyprus: a 20-year retrospective study.

Haemoglobinopathies are the most common monogenic diseases, posing a major public health challenge worldwide. Cyprus has one the highest prevalences of thalassaemia in the world and has been the first country to introduce a successful population-wide prevention programme, based on premarital screening. In this study, we report the most significant and comprehensive update on the status of haemoglobinopathies in Cyprus for at least two decades.

KLF10 gene expression is associated with high fetal hemoglobin levels and with response to hydroxyurea treatment in β-hemoglobinopathy patients.

Aim: In humans, fetal hemoglobin (HbF) production is controlled by many intricate mechanisms that, to date, remain only partly understood.

Patients & Methods: Pharmacogenomic analysis of the effects of hydroxyurea (HU) on HbF production was undertaken in a collection of Hellenic β-thalassemia and sickle cell disease (SCD) compound heterozygotes and a collection of healthy and KLF1-haploinsufficient Maltese adults, to identify genomic signatures that follow high HbF patterns.

Results: KLF10 emerged as a top candidate.