Project description:Beta-thalassemia, a heritable condition of abnormal hemoglobin production, is not a core condition on the United States Recommended Uniform Screening Panel (RUSP) for state and territorial newborn screening (NBS) programs. However, screening for sickle cell disease (which is on the core RUSP) also detects reduced or absent levels of hemoglobin (Hb) A and certain other Hb variants associated with beta-thalassemia and, thus, allows for a timely referral to appropriate healthcare to minimize sequalae of the disease. The Association of Public Health Laboratories' Hemoglobinopathy Workgroup administered a comprehensive survey of all U.S. NBS programs to assess beta-thalassemia testing methodologies, the cutoffs for defining beta-thalassemia major, and the reporting and follow-up practices. Forty-six (87%) of the programs responded. Thirty-nine of the 46 responding programs (85%) report some form of suspected beta-thalassemia; however, the screening methods, the percentage of Hb A used as a cutoff for an indication of beta-thalassemia major, and the screening follow-up vary widely. The standardization of technical and reporting procedures may improve access to specialty care prior to severe complications, increase genetic counseling, and provide data needed to better understand the public health impact and clinical outcomes of beta-thalassemia in the United States.
Project description:BackgroundThe finding of many Thai Hb E-β0-thalassemia patients with non-transfusion dependent thalassemia (NTDT) phenotype without co-inheritance of α-thalassemia has prompted us to investigate the existence of other genetic modifying factors.MethodsStudy was done on 122 adult Thai patients with NTDT Hb E-β-thalassemia patients without co-inheritance of α-thalassemia. Multiple single-nucleotide polymorphisms (SNPs) associated with γ-globin gene expression including the Gγ-XmnI of HBG2 gene, rs2297339, rs4895441, and rs9399137 of the HBS1L-MYB gene, rs4671393 in the BCL11A gene, and G176AfsX179, T334R, R238H and -154 (C-T) in the KLF1 gene were investigated using PCR and related techniques.ResultsHeterozygous and homozygous for Gγ-XmnI of HBG2 gene were detected at 70.5% and 7.4%, respectively. Further DNA analysis identified the rs2297339 (C-T), rs4895441 (A-G), and rs9399137 (T-C) of HBS1L-MYB gene in 86.9%, 25.4%, and 23.0%, respectively. The rs4671393 (G-A) of the BCL11A gene was found at 31.2%. For the KLF1 gene, only T334R was detected at 9.0%.ConclusionsIt was found that these SNPs, when analyzed in combination, could explain the mild phenotypic expression of all cases. These results underline the importance of these informative SNPs on phenotypic expression of Hb E-β-thalassemia patients.
Project description:After years of reliance on transfusion alone to address anemia and suppress ineffective erythropoiesis in β-thalassemia, many new therapies are now in development. Luspatercept, a transforming growth factor-β inhibitor, has demonstrated efficacy in reducing ineffective erythropoiesis, improving anemia, and possibly reducing iron loading. However, many patients do not respond to luspatercept, so additional therapeutics are needed. Several medications in development aim to induce hemoglobin F (HbF): sirolimus, benserazide, and IMR-687 (a phosphodiesterase 9 inhibitor). Another group of agents seeks to ameliorate ineffective erythropoiesis and improve anemia by targeting abnormal iron metabolism in thalassemia: apotransferrin, VIT-2763 (a ferroportin inhibitor), PTG-300 (a hepcidin mimetic), and an erythroferrone antibody in early development. Mitapivat, a pyruvate kinase activator, represents a unique mechanism to mitigate ineffective erythropoiesis. Genetically modified autologous hematopoietic stem cell transplantation offers the potential for lifelong transfusion independence. Through a gene addition approach, lentiviral vectors have been used to introduce a β-globin gene into autologous hematopoietic stem cells. One such product, betibeglogene autotemcel (beti-cel), has reached phase 3 trials with promising results. In addition, 2 gene editing techniques (CRISPR-Cas9 and zinc-finger nucleases) are under investigation as a means to silence BCL11A to induce HbF with agents designated CTX001 and ST-400, respectively. Results from the many clinical trials for these agents will yield results in the next few years, which may end the era of relying on transfusion alone as the mainstay of thalassemia therapy.
Project description:Hemoglobinopathies are among the most common monogenic diseases worldwide. Approximately 1-5% of the global population are carriers for a genetic thalassemia mutation. The thalassemias are characterized by autosomal recessive inherited defects in the production of hemoglobin. They are highly prevalent in the Mediterranean, Middle East, Indian subcontinent, and East and Southeast Asia. Due to recent migrations, however, the thalassemias are now becoming more common in Europe and North America, making this disease a global health concern. Currently available conventional therapies in thalassemia have many challenges and limitations. A better understanding of the pathophysiology of β-thalassemia in addition to key developments in optimizing transfusion programs and iron-chelation therapy has led to an increase in the life span of thalassemia patients and paved the way for new therapeutic strategies. These can be classified into three categories based on their efforts to address different features of the underlying pathophysiology of β-thalassemia: correction of the globin chain imbalance, addressing ineffective erythropoiesis, and improving iron overload. In this review, we provide an overview of the novel therapeutic approaches that are currently in development for β-thalassemia.
Project description:A preclinical humanized mouse model of beta thalassemia major or Cooley anemia (CA) was generated by targeted gene replacement of the mouse adult globin genes in embryonic stem cells. The mouse adult alpha and beta globin genes were replaced with adult human alpha globin genes (alpha2alpha1) and a human fetal to adult hemoglobin (Hb)-switching cassette (gamma(HPFH)deltabeta(0)), respectively. Similar to human infants with CA, fully humanized mice survived postnatally by synthesizing predominantly human fetal Hb, HbF (alpha(2)gamma(2)), with a small amount of human minor adult Hb, HbA2 (alpha(2)delta(2)). Completion of the human fetal to adult Hb switch after birth resulted in severe anemia marked by erythroid hyperplasia, ineffective erythropoiesis, hemolysis, and death. Similar to human patients, CA mice were rescued from lethal anemia by regular blood transfusion. Transfusion corrected the anemia and effectively suppressed the ineffective erythropoiesis, but led to iron overload. This preclinical humanized animal model of CA will be useful for the development of new transfusion and iron chelation regimens, the study of iron homeostasis in disease, and testing of cellular and genetic therapies for the correction of thalassemia.
Project description:Patients with beta-thalassemia major (BTM) suffer from fatigue, poor physical fitness, muscle weakness, lethargy, and cardiac complications which are related to an energy crisis. Carnitine and acylcarnitine derivatives play important roles in fatty acid oxidation, and deregulation of carnitine and acylcarnitine metabolism may lead to an energy crisis. The present study aimed to investigate carnitine and acylcarnitine metabolites to gain an insight into the pathophysiology of BTM. Dried blood spots of 45 patients with BTM and 96 age-matched healthy controls were analyzed for free carnitine and 24 acylcarnitines by using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Although medium chain acylcarnitine levels were similar in the patients with BTM and healthy controls, free carnitine, short chain acylcarnitines, long chain acylcarnitines, and total acylcarnitine levels were significantly lower in patients with BTM than in the healthy controls (P < 0.05). Moreover, an impaired fatty acid oxidation rate was observed in the patients with BTM, as manifested by decreased fatty acid oxidation indicator ratios, namely C2/C0 and (C2 + C3)/C0. Furthermore, an increase in the C0/(C16 + C18) ratio indicated reduced carnitine palmitoyltransferase-1 (CPT-1) activity in the patients with BTM compared with that in the healthy controls. Thus, a low level of free carnitine and acylcarnitines together with impaired CPT-1 activity contribute to energy crisis-related complications in the patients with BTM.
Project description:Thalidomide is a therapeutic option for patients with β-thalassemia by increasing fetal hemoglobin and thereby reducing the requirement for blood transfusions. However, information on changes in erythropoiesis and iron homeostasis during thalidomide treatment is lacking. This study investigated the effects of thalidomide treatment on hematologic, erythropoietic, and ironstatus parameters in 22 patients with transfusion-dependent β-thalassemia (TDT). Thalidomide significantly improved anemia endpoints, including increases in hemoglobin (p<0.001), red blood cells (p<0.001), and hematocrit (p<0.001), as well as reducing erythropoietin levels (p=0.033) and ameliorating erythropoiesis. Thalidomide treatment significantly reduced serum iron levels (p=0.018) and transferrin saturation (p=0.039) and increased serum transferrin levels (p=0.030). Thalidomide had no observed effect on serum ferritin or hepcidin, but changes in hepcidin (r=0.439, p=0.041) and serum iron (r=-0.536, p=0.010) were significantly correlated with hemoglobin increment. This comprehensive study indicates that thalidomide treatment can ameliorate erythropoiesis and iron homeostasis in patients with TDT, thus supporting the effectiveness of this drug.
Project description:ObjectiveTo evaluate the peripartum transfusion rates for rural women compared with urban women in the United States.MethodsIn this population-based retrospective cohort study, geocoded birth records from 2014 to 2016 from the National Center for Health Statistics were used to examine the rural-urban differences in blood transfusion among nulliparous women delivering singleton, vertex pregnancies at term. We compared transfusion rates across the counties on a continuum from urban to rural. We generated a multivariable logistic regression model controlling for age, race, nativity, education, insurance, prenatal care, maternal health, gestational age, intrapartum care, mode of delivery, peripartum factors, and county of delivery.ResultsAmong 3,346,816 births, the transfusion rates based on maternal county of residence increased as the counties became more rural: large metropolitan-center (1.9/1,000 live births); large metropolitan-fringe (2.4); medium metropolitan (2.6); small metropolitan (2.6); micropolitan (4.5); and noncore rural (5.3). Rural women living and delivering in a rural county had more transfusions (8.5/1,000 live births) than women in more urban counties (2.5/1,000). After adjusting for key covariates, the odds of transfusion were higher among women living in micropolitan (adjusted odds ratio [aOR] 2.25, 95% CI 2.09-2.43) and noncore rural (aOR 2.59, 95% CI 2.38-2.81) counties when compared with women living in large metropolitan counties. County of delivery had a higher association with transfusion than resident county. After adding delivery county to the regression model, the association of transfusion and living in a micropolitan (aOR 1.39, 95% CI 1.19-1.63) or noncore rural (aOR 1.32, 95% CI 1.12-1.55) county diminished.ConclusionThe odds of blood transfusion were higher for women in rural areas. The results indicate that the rurality of the county where the birth occurred was associated with more transfusion. This may reflect differences in maternity and blood banking services in rural hospitals and warrants further study to identify opportunities for intervention.