Chronic Hemolytic Anemia Research Articles

Promising role of Voxelotor in managing sickle cell disease in children: a narrative review.

Sickle cell disease (SCD) is characterized by chronic hemolytic anemia and intermittent vaso-occlusive crises. To date, four disease-modifying drugs have been approved for the treatment of SCD: hydroxyurea (an S-phase inhibitor), L-glutamine (an amino acid), crizanlizumab (a P-selectin inhibitor), and voxelotor (a hemoglobin S polymerization inhibitor). Preclinical studies suggested that voxelotor effectively treats SCD and sickle cell anemia (SCA). In a phase III trial, voxelotor-treated patients showed significantly elevated hemoglobin levels (>1 g/dL from baseline) compared to placebo-treated patients. The group that received voxelotor also showed a greater decrease in hemolytic markers but a comparable incidence of side effects. Six ongoing clinical trials also sought to ascertain the effectiveness and safety of high-dose voxelotor when administered to children younger than 12 years. Studies assessing their long-term efficacy and safety are needed to fully understand the role of voxelotor in treating SCD/SCA. In this review, we discuss the mechanisms, trials to date, and future treatment directions of voxelotor.

Erythropoiesis and Gene Expression Analysis in Erythroid Progenitor Cells Derived from Patients with Hemoglobin H/Constant Spring Disease.

Hemoglobin H/Constant Spring (Hb H/CS) disease represents a form of non-deletional Hb H disease characterized by chronic hemolytic anemia that ranges from moderate to severe and may lead to transfusion-dependent thalassemia. To study the underlying mechanisms of this disease, we conducted an analysis of erythropoiesis and gene expression in erythroid progenitor cells derived from CD34+ hematopoietic stem/progenitor cells from patients with Hb H/CS disease and normal controls. Twelve patients with Hb H/CS disease and five normal controls were enrolled. Peripheral blood samples were collected to isolate CD34+ hematopoietic stem/progenitor cells for the analysis of cell proliferation and differentiation. Six samples from patients with Hb H/CS disease and three controls were subsequently studied for gene expression by next generation sequencing analysis. Erythroid progenitor cells derived from patients with Hb H/CS disease exhibited a trend towards increased rates of erythroid proliferation and decreased cell viability compared to those from controls. Moreover, erythroid progenitor cells derived from patients with Hb H/CS disease demonstrated delayed terminal differentiation. Gene expression profiling revealed elevated levels of genes encoding molecular chaperones, including the heat shock protein genes (HSPs) and the chaperonin containing TCP-1 subunit genes (CCTs) in the Hb H/CS disease group. In summary, erythroid progenitor cells derived from patients with Hb H/CS disease exhibit a trend towards heightened erythroid proliferation, diminished cell viability, and delayed terminal differentiation. Additionally, the increased expression of genes encoding molecular chaperones was observed, providing information on potential underlying pathophysiological mechanisms.

Cold autoantibody interference in pretransfusion testing and its resolution: a case report

We report a case of cold autoantibody detected in a 69-year-old gentleman diagnosed with chronic lymphocytic leukemia and cold autoimmune hemolytic anaemia. Pretransfusion testing showed panagglutination in ABO grouping, antibody screening and identification, with positive direct antiglobulin test (DAT) and positive control cells. A cold autoantibody was suspected, however, the test using a prewarm method and washed RBC with warm saline failed to resolve it. Further tests using DTT-treated cells resolved the grouping as AB RhD positive and DAT as positive with anti-C3d only (control negative). Cold autoadsorption was done and repeated antibody screening using cold-autoadsorped plasma was negative, excluding the presence of alloantibody. The cold-agglutinin titer was >1028 having a wide thermal range. Crossmatching using cold autoadsorped plasma with the AB-positive donor blood was compatible and the patient was transfused safely. For such cold autoantibody cases, an extensive immunohematological workup is required to exclude underlying alloantibody for transfusion safety and efficacy. Bangladesh Journal of Medical Science Vol. 23 No. 04 October’24 Page : 1238-1242

Impact of Empagliflozin on the Outcomes of β-Thalassemia Major in Patients With Type 2 Diabetes Mellitus: The THALEMPA Observational Study.

Beta-thalassemia major (β-TM) is a genetic disorder characterized by ineffective erythropoiesis and chronic hemolytic anemia, necessitating lifelong blood transfusions and leading to severe complications. This study, termed THALEMPA by the authors, investigated the effect of empagliflozin (EMPA) on β-TM outcomes in patients with type 2 diabetes mellitus (T2DM), focusing on disease severity and associated complications of iron overload and hyperuricemia. This study conducted a single-center prospective observational investigation involving adults diagnosed with β-TM and T2DM. A total of 20 carefully selected patients were stratified into two groups based on their medical condition: the EMPA group, receiving 10 mg of empagliflozin, and a control group, receiving standard care. This focused cohort size was chosen to ensure a detailed, in-depth analysis of the treatment effects within this specific patient population. Over three months, both groups were closely monitored for β-TM outcomes. The study assessed β-TM severity parameters such as hemoglobin levels, blood transfusion frequency, aspartate aminotransferase (AST), alanine aminotransferase (ALT), left ventricular ejection fraction percentage, and spleen size. Additionally, β-TM complications were evaluated through serum ferritin and uric acid levels. Our analysis revealed that EMPA increased hemoglobin levels by up to 0.56 g/dL compared to baseline (P< 0.05). Liver enzyme levels significantly improved with EMPA by the third month. AST and ALT decreased by 36.22% and 33.36%, respectively, from baseline levels (P< 0.05), highlighting EMPA's potential benefits for β-TM severity. Serum ferritin and uric acid levels decreased by 27.93% and 21.29%, respectively, over three months on EMPA (P< 0.05). However, other parameters did not show significant changes post-EMPA. This study demonstrates the significant impact of EMPA treatment over three months on β-TM patients with T2DM, evidenced by notable improvements in hemoglobin levels and reductions in liver enzymes, as well as in complications related to iron overload and hyperuricemia. Future research should confirm these benefits over longer durations and assess broader patient outcomes such as quality of life.

Exercise and training in sickle cell disease: Safety, potential benefits, and recommendations.

Sickle cell disease (SCD) is a genetic disorder characterized by complex pathophysiological mechanisms leading to vaso-occlusive crisis, chronic pain, chronic hemolytic anemia, and vascular complications, which require considerations for exercise and physical activity. This review aims to elucidate the safety, potential benefits, and recommendations regarding exercise and training in individuals with SCD. SCD patients are characterized by decreased exercise capacity and tolerance. Acute intense exercise may be accompanied by biological changes (acidosis, increased oxidative stress, and dehydration) that could increase the risk of red blood cell sickling and acute clinical complications. However, recent findings suggest that controlled exercise training is safe and well tolerated by SCD patients and could confer benefits in disease management. Regular endurance exercises of submaximal intensity or exercise interventions incorporating resistance training have been shown to improve cardiorespiratory and muscle function in SCD, which may improve quality of life. Recommendations for exercise prescription in SCD should be based on accurate clinical and functional evaluations, taking into account disease phenotype and cardiorespiratory status at rest and in response to exercise. Exercise programs should include gradual progression, incorporating adequate warm-up, cool-down, and hydration strategies. Exercise training represents promising therapeutic strategy in the management of SCD. It is now time to move through the investigation of long-term biological, physiological, and clinical effects of regular physical activity in SCD patients.

Assessment of Serum Autophagy Related Protein Beclin1 in Egyptian Adult Beta Thalathemic Patients

Abstract Background Beta-thalassemia is a chronic hemolytic anemia that is inherited in an autosomal recessive manner. It is characterized by reduced hemoglobin levels and red blood cell production. Aim of the Work Assessment of serum autophagy related protein beclin1 in Egyptian adult beta thalathemic patients and Its relation to ineffective erythropoiesis, transfusion requirements, iron overload. Subjects and Methods This is a case control study which was carried out at Ain Shams university hospitals. Internal medicine department, Clinical hematology and stem cell transplantation unit, outpatient clinic and inpatient department, during the period between January 2022 and August 2022. Results Our study revealed significant decreased fertility between patients group and control group (P = 0.011). Transfusion-dependent beta-thalassemia males have a high proportion of fertility impairment and iron overload might contribute to disturbed sperm quality and testicular tissue injury. Such findings might explain the high prevalence of impaired fertility in transfusion-dependent beta- thalassemia patients which agrees with our results. Also our study revealed significant differences between non-transfusion dependent group and transfusion-dependent group regarding spleen size (cm) below costal margin which was increased in (TD group), transfusion per year (ml/yr)(which was increased in (TD group), virology (HIV, HCV,HBV) revealed that percentage of HCV+ve higher in (TD group) with (P &amp;lt; 0.001): Our study revealed significant difference between non-transfusion- dependent group and Transfusion-dependent group regarding percentage of patients of with positive HCV which was increased in Transfusion-dependent group (P = 0.021): In our study Iron chelation therapy was found to be given in a higher percentage of TD patients compared to non TD patients (P &amp;lt; 0.001). Also our study revealed significant difference regarding cardic function(EF%) between patients group and control group (EF found to be lower in patients group than controls) (P &amp;lt; 0.001): Also our study showed that Beclin-1 level is significantly higher in patients group compared to control group (P &amp;lt; 0.001). We couldn’t find previous studies of Beclin-1 level in thalassemia patients. We postulate that Beclin 1 could be used as a marker of worsening cardiac functions in thalassemia patients, but further studies should measure serial levels of Beclin 1 and correlate it with cardiac parameters over longer periods of follow up. Conclusion Beclin 1 level increased in Adult Beta Thalasemia patients and it can be used as a prognostic marker for Adult Beta Thalasemia patients.

Pyruvate kinase deficiency in 29 Turkish patients with two novel intronic variants.

Pyruvate kinase (PK) is a key enzyme of anaerobic glycolysis. The genetic heterogeneity of PK deficiency (PKD) is high, and over 400 unique variants have been identified. Twenty-nine patients who had been diagnosed as PKD genetically in seven distinct paediatric haematology departments were evaluated. Fifteen of 23 patients (65.2%) had low PK levels. The PK:hexokinase ratio had 100% sensitivity for PKD diagnosis, superior to PK enzyme assay. Two novel intronic variants (c.695-1G>A and c.694+43C>T) have been described. PKD should be suspected in patients with chronic non-spherocytic haemolytic anaemia, even if enzyme levels are falsely normal. Total PKLR gene sequencing is necessary for the characterization of patients with PKD and for genetic counselling.

Controversies in the pathophysiology of leg ulcers in sickle cell disease.

Patients with sickle cell disease (SCD) often experience painful vaso-occlusive crises and chronic haemolytic anaemia, as well as various acute and chronic complications, such as leg ulcers. Leg ulcers are characterized by their unpredictability, debilitating pain and prolonged healing process. The pathophysiology of SCD leg ulcers is not well defined. Known risk factors include male gender, poor social conditions, malnutrition and a lack of compression therapy when oedema occurs. Leg ulcers typically start with spontaneous pain, followed by induration, hyperpigmentation, blister formation and destruction of the epidermis. SCD is characterized by chronic haemolysis, increased oxidative stress and decreased nitric oxide bioavailability, which promote ischaemia and inflammation and consequently impair vascular function in the skin. This cutaneous vasculopathy, coupled with venostasis around the ankle, creates an ideal environment for local vaso-occlusive crises, which can result in the development of leg ulcers that resemble arterial ulcers. Following the development of the ulcer, healing is hindered as a result of factors commonly observed in venous ulceration, including venous insufficiency, oedema and impaired angiogenesis. All of these factors are modulated by genetic factors. However, our current understanding of these genetic factors remains limited and does not yet enable us to accurately predict ulceration susceptibility.

Exploring the Interplay between Asthma and Hemoglobinopathies: A Comprehensive Review.

Asthma, a prevalent chronic respiratory condition characterized by inflammation of the airways and bronchoconstriction, has demonstrated a potential association with hemoglobinopathies such as thalassemia and sickle cell disease (SCD). Numerous studies have highlighted a higher prevalence of asthma among thalassemia patients compared to the general population, with rates ranging around 30%. Similarly, asthma frequently coexists with SCD, affecting approximately 20-48% of patients. Children with SCD often experience heightened lower airway obstruction and airway hyper-reactivity. Notably, the presence of asthma in SCD exacerbates respiratory symptoms and increases the risk of severe complications like acute chest syndrome, stroke, vaso-occlusive episodes, and early mortality. Several studies have noted a decrease in various cytokines such as IFN-γ and IL-10, along with higher levels of both IL-6 and IL-8, suggesting an overactivation of pro-inflammatory mechanisms in patients with hemoglobinopathies, which could trigger inflammatory conditions such as asthma. The exact mechanisms driving this association are better elucidated but may involve factors such as chronic inflammation, oxidative stress, and immune dysregulation associated with thalassemia-related complications like chronic hemolytic anemia and iron overload. This review aims to comprehensively analyze the relationship between asthma and hemoglobinopathies, with a focus on thalassemia and SCD. It emphasizes the importance of interdisciplinary collaboration among pulmonologists, hematologists, and other healthcare professionals to effectively manage this complex interplay. Understanding this link is crucial for improving care and outcomes in affected individuals.

Malnutrition in sickle cell anemia: Prevalence, impact, and interventions: A Review.

Sickle Cell Anemia (SCA) is a hereditary hemoglobinopathy characterized by chronic hemolytic anemia, vaso-occlusive events, and a wide range of clinical complications. Malnutrition, often an underexplored aspect of this complex condition, plays a critical role in disease management and overall patient well-being. This publication provides a comprehensive review of the prevalence, impact, and interventions related to malnutrition in individuals with SCA. A thorough literature review reveals the multifaceted challenges faced by SCA patients in maintaining adequate nutrition. The pathophysiology of SCA, involving chronic inflammation, oxidative stress, and hypermetabolism, contributes to increased nutritional requirements and altered dietary patterns. Factors such as reduced appetite, nutrient malabsorption, dietary restrictions, and socioeconomic disparities further exacerbate the risk of malnutrition. Malnutrition is a prevalent issue among individuals with SCA, affecting patients of different age groups and disease severities. Nutritional deficiencies, including vitamins, minerals, and essential nutrients, are common in this population. The impact of malnutrition on disease outcomes is significant, with associations between nutrient status and complications such as pain crises, infections, and impaired quality of life. This paper also reviews nutritional interventions aimed at addressing malnutrition in SCA patients. While dietary counseling, supplementation, and personalized nutrition plans have shown promise in improving nutritional status, challenges such as patient adherence and access to healthcare must be addressed to optimize their effectiveness.

Unveiling Extramedullary Hematopoiesis: A Case Report Highlighting the Causes, Symptoms, and Management Strategies

Extramedullary hematopoiesis (EMH) serves as a compensatory mechanism in chronic hemolytic anemias, such as thalassemia, and can result in spinal cord compression. This case report highlights a 36-year-old woman with transfusion-dependent β-thalassemia (TDT) who presented with lower extremity motor deficiency, pelvic paresthesia, and bladder dysfunction. The patient had a history of lower back pain, bilateral lower limb weakness, and demonstrated poor compliance with iron chelation therapy. MRI findings indicated spinal cord compression attributable to extramedullary hematopoiesis. Due to the infeasibility of surgical intervention, the patient underwent hypertransfusion and iron chelation therapy. While neurological symptoms improved, urinary retention persisted. The patient continues to receive iron chelation treatment and undergo transfusions. Managing extramedullary hematopoiesis in thalassemia necessitates an individualized treatment approach.

Enhancing Disease Diagnosis: Statistical Analysis of Haematological Parameters in Sickle Cell Patients, Integrating Predictive Analytics

Sickle cell disease (SCD) affects 30 million people worldwide, causing a range of symptoms from mild to severe, including Vaso occlusive crises (VOC). SCD leads to damaging cycles of sickling and desickling of red blood cells due to HbS polymer formation, resulting in chronic haemolytic anaemia and tissue hypoxia. We propose using machine learning to categorize SCD patients based on haemoglobin, reticulocyte count, and LDH levels, crucial markers of hemolysis. Statistical analysis, particularly Linear Regression, demonstrates how haemoglobin depletion occurs using LDH and reticulocyte parameters.&#x0D; Bilirubin and haemoglobin, two integral biomarkers in clinical biochemistry and haematology, serve distinct yet interconnected roles in human physiology. Bilirubin, a product of heme degradation, is a critical indicator of liver function and various hepatic disorders, while haemoglobin, found in red blood cells, is responsible for oxygen transport throughout the body. Understanding the statistical relationship between these biomarkers has far-reaching clinical implications, enabling improved diagnosis, prognosis, and patient care. This research paper conducts a comprehensive statistical analysis of bilirubin and haemoglobin using various regression techniques to elucidate their intricate association. The primary objective of this study is to characterize the relationship between bilirubin and haemoglobin. Through meticulous data analysis, we explore whether these biomarkers exhibit positive, negative, or no correlation. Additionally, this research develops predictive models for estimating haemoglobin levels based on bilirubin data, offering valuable tools for healthcare professionals in clinical practice.

Constructing a novel clinical indicator model to predict the occurrence of thalassemia in pregnancy through machine learning algorithm

Thalassemia is one of the inherited hemoglobin disorders worldwide, resulting in ineffective erythropoiesis, chronic hemolytic anemia, compensatory hemopoietic expansion, hypercoagulability, etc., and when a mother carries the thalassemia gene, the child is more likely to have severe thalassemia. Furthermore, the economic and time costs of genetic testing for thalassemia prevent many thalassemia patients from being diagnosed in time. To solve this problem, we performed least absolute shrinkage and selection operator (LASSO) regression to analyze the correlation between thalassemia and blood routine indicators containing mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), and red blood cell (RBC). We then built a nomogram to predict the occurrence of thalassemia, and receiver operating characteristic (ROC) curve was used to verify the prediction efficiency of this model. In total, we obtained 7,621 cases, including 847 thalassemia patients and 6,774 non-thalassemia. Among the 847 thalassemia patients, with a positivity rate of 67.2%, 569 cases were positive for α-thalassemia, and with a rate of 31.5%, 267 cases were positive for β-thalassemia. The remaining 11 cases were positive for both α- and β-thalassemia. Based on machine learning algorithm, we screened four optimal indicators, namely, MCV, MCH, RBC, and MCHC. The AUC value of MCV, MCH, RBC, and MCHC were 0.907, 0.906, 0.796, and 0.795, respectively. Moreover, the AUC value of the prediction model was 0.911. In summary, a novel and effective machine learning model was built to predict thalassemia, which functioned accurately, and may provide new insights for the early screening of thalassemia in the future.

A novel frameshift mutation in RHAG leads to Rhnull phenotype in a Chinese individual.

We recently encountered a Rhnull phenotype proband within one family in the Chinese population. Rhnull is a rare autosomal recessive disorder characterized by the absence of the Rh antigens on the erythrocyte membrane, resulting in chronic hemolytic anemia. This study described the serological and molecular analysis of a Chinese Rhnull proband and his immediate family. Red blood cells antigen phenotyping and antibody screening/identification were conducted. RHD, RHCE, and RHAG were analyzed using genomic DNA by polymerase chain reaction and sequence analysis. Serologic tests showed a D-C-E-c-e- phenotype in the proband associated with the suspicion of anti-Rh29 (titer 16). Molecular analyses showed a new mutation (c.406dupA) in exon 3 of RHAG. This duplication introduced a reading frameshift (p.Thr136AsnfsTer21). The RHAG mutation was found in the homozygous state for the proband and heterozygous state for his parents. We identified a novel RHAG mutation resulting in the Rhnull phenotype of the regulator type. Inheritance of the novel allele was shown by family study.

Diagnosis andmanagement of chronic thromboembolic pulmonary hypertension (CTEPH) in sickle cell disease: A review.

Pulmonary hypertension in sickle cell disease (SCD) is a complex phenomenon resulting from multiple overlapping etiologies, including pulmonary vasoconstriction in the setting of chronic hemolytic anemia, diastolic dysfunction, and chronic thromboembolic disease. The presence of pulmonary hypertension of any cause in SCD confers a significant increase in mortality risk. Evidence to guide the management of patients with sickle cell disease and chronic thromboembolic pulmonary hypertension(CTEPH) is scant and largely the realm of case reports and small case series. Centered on a discussion of a complex young patient with hemoglobin hemoglobin SC who ultimately underwent treatment with pulmonary thromboendarterectomy, we review the available literature to guide management and discuss and overview of treatment of CTEPH in SCD, considering the unique considerations and challenges facing patients suffering from this multisystem disease.

Hypoparathyroidism in Patients Older than 10 Years of Age with Beta-thalassemia

Abstract: BACKGROUND: Despite prolonged life expectancy in patients with beta-thalassemia due to modern chelation therapy and planned blood transfusions, they still suffer from multisystem complications of this chronic hemolytic anemia, including endocrine system dysfunction. Under-recognized parathyroid hormone (PTH) dysfunction in these patients can manifest as bone pain and fractures. OBJECTIVE: The objective of the study was to evaluate PTH in patients with beta-thalassemia &gt;10 years of age. METHODS: A cross-sectional study was performed on 76 randomly selected patients &gt;10 years old with beta-thalassemia (including both thalassemia major and thalassemia intermedia) in the Al-Kut Hereditary Blood Disease Center in Wasit province, Iraq. The study covered the period from November 2021 to April 2022. Data were collected from patients’ files after written consent, including sex, age, ferritin level, mean hemoglobin level, type of chelation therapy, frequency of transfusion, mean calcium level, and whether the patients were splenectomized or not. RESULTS: Of the 76 patients enrolled in the study, 39 (51.3%) were males. There were 63 (82.9%) who had thalassemia major. The majority of cases (n = 55, 71%) were from the age group &gt;15 years. Fifteen (19.7%) patients had low PTH levels. The age group &gt;15 years had a higher frequency of having low PTH levels (P = 0.01 and Pearson factor - 0.29). The study found a positive correlation between low calcium and low PTH levels (P = 0.001, Pearson factor = 0.1). High ferritin levels had no significant correlation with PTH levels (P = 0.4). CONCLUSIONS: Beta-thalassemia patients can have a low PTH level. It can occur more often in patients &gt;15 years old, which necessitates close monitoring for older thalassemia patients. A declining calcium level in these patients can correlate with a low PTH level.

Glucose phosphate isomerase deficiency demasked by whole-genome sequencing: a case report

BackgroundGlucose-6-phosphate isomerase deficiency is a rare genetic disorder causing hereditary nonspherocytic hemolytic anemia. It is the second most common glycolytic enzymopathy in red blood cells. About 90 cases are reported worldwide, with symptoms including chronic hemolytic anemia, jaundice, splenomegaly, gallstones, cholecystitis, and in severe cases, neurological impairments, hydrops fetalis, and neonatal death.Case presentationThis paper details the case of the first Danish patient diagnosed with glucose-6-phosphate isomerase deficiency. The patient, a 27-year-old white female, suffered from lifelong anemia of unknown origin for decades. Diagnosis was established through whole-genome sequencing, which identified two GPI missense variants: the previously documented variant p.(Thr224Met) and a newly discovered variant p.(Tyr341Cys). The pathogenicity of these variants was verified enzymatically.ConclusionsWhole-genome sequencing stands as a potent tool for identifying hereditary anemias, ensuring optimal management strategies.

Evaluation of the impact of two C5 genetic variants on C5-eculizumab complex stability at the molecular level

Complement C5 is the target of the monoclonal antibody eculizumab, used in complement dysregulating disorders, like the rare disease Paroxysmal Nocturnal Hemoglobinuria (PNH). PNH is an acquired hematopoietic stem cell condition characterized by aberrant destruction of erythrocytes, chronic hemolytic anemia, and thromboembolism propensity. C5 is a protein component of the complement system which is part of the immune system of the body and plays a prominent role in the destruction of red blood cells, misidentifying them as a threat. This work describes the application of molecular dynamics simulations to the study of the underlying interactions between complement C5 and eculizumab. This study also reveals the importance of single nucleotide polymorphisms on C5 protein concerning the effective inhibition of the mAB, involving the mechanistic events taking place at the interface spots of the complex. The predicted conformational change in the C5 Arg885/His/Cys mutation has implications on the protein’s interaction with eculizumab, compromising their compatibility. The acquired insights into the conformational changes, dynamics, flexibility, and interactions shed light on the knowledge of the function of this biomolecule providing answers about the poor response to the treatment in PNH patient carriers of the mutations. By investigating the intricate dynamics, significant connections between C5 and eculizumab can be uncovered. Such insights may aid in the creation of novel compounds or lead to the enhancement of eculizumab’s efficacy. Communicated by Ramaswamy H. Sarma

Thrombosis Tendency After Splenectomy in a Danish Family With Hemoglobin Volga, and a Literature Review

Hemoglobin (Hb) Volga is a rare, unstable β-chain hemoglobin variant (β27 Ala→Asp), causing chronic hemolytic anemia. This study presents two members of a Danish family, splenectomized due to Hb Volga at and with multiple thrombotic events. The proband was diagnosed with Hb Volga 9 years old and splenectomy was performed as a part of treatment. Throughout his life, he experienced multiple superficial thrombophlebitis, two episodes of distal deep venous thrombosis (DVT) on lower extremities (age 32 and 33) and a transient ischemic attack (TIA) presented as amaurosis fugax (age 51). Thrombophilia investigation was normal. The proband’s son was diagnosed with Hb Volga and underwent splenectomy at the age of 6. Despite anticoagulation therapy, he suffered from multiple venous thromboembolic events in his youth and died of chronic pulmonary embolism (PE)/pulmonary hypertension combined with infection. Given the observed propensity for multiple thromboses in these two patients, a literature review was conducted investigating reported occurrence of thrombotic events in individuals with Hb Volga. Currently 25 cases of Hb Volga are reported worldwide. The clinical symptoms primarily described are related to hemolytic anemia. Splenectomy is reported in 15 patients. Thromboses have previously been reported in only three patients who were also splenectomized. These cases involved DVT and PE, myocardial infarction, and an unspecified thrombotic event. The proband represents the first reported Hb Volga case with both venous and arterial thrombotic disorders. The exact mechanism underlying thrombotic tendency in patients with Hb Volga remains unknown, but it is probably associated with splenectomy.

PKLR mutations in pyruvate kinase deficient Polish patients: Functional characteristics of c.101-1G > A and c.1058delAAG variants

Pyruvate kinase (PK) deficiency is a rare autosomal recessive disorder characterized by chronic hemolytic anemia of variable severity. Nine Polish patients with severe hemolytic anemia but normal PK activity were found to carry mutations in the PKLR gene encoding PK, five already known ones and one novel (c.178C > T). We characterized two of the known variants by molecular modeling (c.1058delAAG) and minigene splicing analysis (c.101-1G > A). The former gives a partially destabilized PK tetramer, likely of suboptimal activity, and the c.101-1G > A variant gives alternatively spliced mRNA carrying a premature stop codon, encoding a severely truncated PK and likely undergoing nonsense-mediated decay.