Nonspherocytic Hemolytic Anemia Research Articles

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.

Pyruvate kinase deficiency: A case series of congenital non-spherocytic hemolytic anemia

BackgroundPyruvate kinase deficiency (PKD) is a common cause of congenital non-spherocytic hemolytic anemia (CNSHA). The heterogeneity of clinical presentation complicates the diagnosis and management of this disease. The objective was to describe the clinical, laboratory, and genetic profile of pediatric patients with PKD. Material and methodsIt was a retrospective, observational study. Children and their family members presenting to the Department of Pediatric Hematology and Oncology, St John's Medical College Hospital Bangalore, India, and diagnosed with PKD during 2011–2023 were enrolled. ResultsEight patients were identified through retrospective chart reviews. Four cases were clustered in one family and affected twins in the second family. All patients had a history of neonatal jaundice; however, they varied in their severity and the requirement for transfusion support. Some patients underwent splenectomy and one had hematopoietic stem cell transplant. ConclusionPKD is a known cause of congenital non-spherocytic hemolytic anemia with heterogeneous presentation. A high index of suspicion, enzyme assay, and genetic studies are required for diagnosis.

Genetic Analysis of Two Novel GPI Variants Disrupting H Bonds and Localization Characteristics of 55 Gene Variants Associated with Glucose-6-phosphate Isomerase Deficiency.

Glucose-6-phosphate isomerase (GPI) deficiency is a rare hereditary nonspherocytic hemolytic anemia caused by GPI gene variants. This disorder exhibits wide heterogeneity in its clinical manifestations and molecular characteristics, often posing challenges for precise diagnoses using conventional methods. To this end, this study aimed to identify the novel variants responsible for GPI deficiency in a Chinese family. The clinical manifestations of the patient were summarized and analyzed for GPI deficiency phenotype diagnosis. Novel compound heterozygous variants of the GPI gene, c.174C>A (p.Asn58Lys) and c.1538G>T (p.Trp513Leu), were identified using whole-exome and Sanger sequencing. The AlphaFold program and Chimera software were used to analyze the effects of compound heterozygous variants on GPI structure. By characterizing 53 GPI missense/nonsense variants from previous literature and two novel missense variants identified in this study, we found that most variants were located in exons 3, 4, 12, and 18, with a few localized in exons 8, 9, and 14. This study identified novel compound heterozygous variants associated with GPI deficiency. These pathogenic variants disrupt hydrogen bonds formed by highly conserved GPI amino acids. Early family-based sequencing analyses, especially for patients with congenital anemia, can help increase diagnostic accuracy for GPI deficiency, improve child healthcare, and enable genetic counseling.

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.

Subnormal Serum Liver Enzyme Levels: A Review of Pathophysiology and Clinical Significance.

Subnormal levels of liver enzymes, below the lower limit of normal on local laboratory reports, can be useful diagnostically. For instance, subnormal levels of aminotransferases can be observed in vitamin B6 deficiency and chronic kidney disease. Subnormal alkaline phosphatase levels may indicate the presence of hypophosphatasia, Wilson's disease, deficiencies of divalent ions, or malnutrition. Subnormal levels of gamma glutamyl transferase may be seen in cases of acute intrahepatic cholestasis, the use of certain medications, and in bone disease. Finally, subnormal levels of 5'-nucleotidase have been reported in lead poisoning and nonspherocytic hemolytic anemia. The aim of this review is to bring attention to the fact that subnormal levels of these enzymes should not be ignored as they may indicate pathological conditions and provide a means of early diagnosis.

Biallelic hexokinase 1 (HK1) variants causative of non-spherocytic haemolytic anaemia: A case series with emphasis on the HK1 promoter variant and literature review.

The hexokinase (HK) enzyme plays a key role in red blood cell energy production. Hereditary non-spherocytic haemolytic anaemia (HNSHA) caused by HK deficiency is a rare disorder with only 12 different disease-associated variants identified. Here, we describe the clinical features and genotypes of four previously unreported patients with hexokinase 1 (HK1)-related HNSHA, yielding two novel truncating HK1 variants. The patients' phenotypes varied from mild chronic haemolytic anaemia to severe infantile-onset transfusion-dependent anaemia. Three of the patients had mild haemolytic disease caused by the common HK1 promoter c.-193A>G variant combined with an intragenic HK1 variant, emphasizing the importance of including this promoter variant in the haemolytic disease gene panels. HK activity was normal in a severely affected patient with a homozygous HK1 c.2599C>T, p.(His867Tyr) variant, but the affinity for ATP was reduced, hampering the HK function. In cases of HNSHA, kinetic studies should be considered in the functional studies of HK. We reviewed the literature of previously published patients to provide better insight into this rare disease and add to the understanding of genotype-phenotype correlation.

Five Novel Hemizygous Variants in the PGK1 Gene Associated with Neurological Dysfunction and Mild Hemolytic Anemia in Five Indian Patients

Introduction Phosphoglycerate kinase (ATP: 3-phosphoglycerate 1-phosphotransferase; EC 2.7.2.3; PGK) is the crucial enzyme of the glycolytic pathway, catalyzing1, 3 bis-phosphoglycerate to 3-Phosphoglycerate, generating one molecule of ATP [1]. PGK enzyme is encoded by the PGK1 gene located at Xq13.3, measures 23kb in size, and spans into 11 exons. PGK deficiency is an X-linked disorder associated with a very rare cause of hereditary non-spherocytic hemolytic anemia (HNSHA). PGK1 gene is ubiquitously expressed but the patients exhibit three major symptoms -1) haemolytic anemia 2) myopathy (rhabdomyolysis), 3) mental retardation and various neurological manifestations[1]. The severity of symptoms varies among patients with PGK deficiency. PGK deficiency is reported worldwide, although to our knowledge no case with Indian ancestry has been reported. Method Genomic DNA was extracted from the EDTA blood sample and processed for targeted Next Generation Sequencing (t-NGS) as per the manufacturer's protocol. The t-NGS panel broadly consists of 80 genes of the spectrum of the disorder including congenital hemolytic anemia, bone marrow failure disorders, and iron deficiency anemia. The libraries were sequenced to >80-100X mean coverage on the Illumina sequencing platform. The variants were classified based on ACMG guidelines. The impact of non-synonymous variations was estimated using PolyPhen-2, SIFT, MutationTaster2, CADD Phred, and Mutpred2. In silico effect of the variant was studied by PyMol. Latter the enzyme deficiency was confirmed by standard protocol and parental segregation analysis was performed. Relative quantification (qPCR) was evaluated based on the comparative CT method ( 2 − ΔΔCT). Result We report five male children of <4 years of age with PGK deficiency from Indian origin. Clinically, all of them manifest global development delay and no speech. Autism spectrum disorder is observed in two of the cases, incidence of seizure and convulsion are present in two cases. None except one, presented with haemolytic anaemia and was given one transfusion post an episode of seizure at the age of 2 years. Additionally, a family history of haemolytic anemia with developmental delay and seizure was present in only one case although the patient himself required no transfusion requirement to date. All the patients are routinely followed up for any evidence of a haemolytic crisis, transfusion requirement, or any other clinical symptoms. Detailed phenotypes of all the patients are listed in Table 1. t-NGS revealed five novel hemizygous variants in the PGK1 gene - p. Cys50Trp, p. Gly137Trp, p. Val140Ile, p. Asp159Asn, and p. Arg330Trp. These variants have not been reported in the literature or available databases. DNA Sanger sequencing confirmed the heterozygous state in the mothers. In silico tools confirmed the pathogenicity of the variants. The PGK enzymatic activity was markedly reduced. The PGK1 transcript levels were reduced to 60% in patients as compared to the healthy controls. Discussion To date, only 34 mutations are known to be associated with PGK enzyme deficiency. Amongst them, 50% of variants exhibit symptoms of anaemia whereas the remaining show neurological and /or myopathy. Figure 1 illustrates all 39 mutations reported with PGK deficiency. Only four mutations p.E120K, p.G158R, p.A354P, and p.I371K are known to exhibit all three categories of symptom (PGK-anaemia-neurological-myopathy)[2]. Conclusion NGS allows for the identification of novel genetic variants that may contribute to the development of rare disorders, expanding our knowledge of their underlying mechanisms. This advanced technology also enables researchers to analyze multiple genes simultaneously, increasing the efficiency and speed of diagnosis in unexplained cases of HNSHA.

Unusual case of cold agglutination induced hemolysis in a child with systemic lupus erythematosus

Autoimmune hemolytic anemia (AIHA) is a common symptom of systemic lupus erythematosus (SLE), but cold agglutinin disease is uncommon. We describe a rare instance of cold agglutinin causing hemolytic anemia in an eight-year-old girl who had a history of maternal antiphospholipid antibody syndrome. The girl had hemolytic anemia, and the Coombs test revealed both warm and cold antibodies with a significant titer of cold agglutinin. Whole exon sequencing revealed a heterozygous mutation in the GPI gene, which was previously described for non-spherocytic hemolytic anemia, but its significance in SLE is unknown. Patient responded to corticosteroids and azathioprine. The purpose of this article is to highlight this extremely rare SLE manifestation and compare it to previously reported cases.

Genetic variants causing G6PD deficiency: Clinical and biochemical data support new WHO classification.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency in erythrocytes causes acute haemolytic anaemia upon exposure to fava beans, drugs, or infection; and it predisposes to neonatal jaundice. The polymorphism of the X-linked G6PD gene has been studied extensively: allele frequencies of up to 25% of different G6PD deficient variants are known in many populations; variants that cause chronic non-spherocytic haemolytic anaemia (CNSHA) are instead all rare. WHO recommends G6PD testing to guide 8-aminoquinolines administration to prevent relapse of Plasmodium vivax infection. From a literature review focused on polymorphic G6PD variants we have retrieved G6PD activity values of 2291 males, and for the mean residual red cell G6PD activity of 16 common variants we have obtained reliable estimates, that range from 1.9% to 33%. There is variation in different datasets: for most variants most G6PD deficient males have a G6PD activity below 30% of normal. There is a direct relationship between residual G6PD activity and substrate affinity (Km G6P ), suggesting a mechanism whereby polymorphic G6PD deficient variants do not entail CNSHA. Extensive overlap in G6PD activity values of individuals with different variants, and no clustering of mean values above or below 10% support the merger of class II and class III variants.

A computational study of structural analysis of Class I human glucose-6-phosphate dehydrogenase (G6PD) variants: Elaborating the correlation to chronic non-spherocytic hemolytic anemia (CNSHA)

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common human enzyme defect that affects more than 500 million people worldwide. Individuals affected with G6PD deficiency may occasionally suffer mild-to-severe chronic hemolytic anemia. Chronic non-spherocytic hemolytic anemia (CNSHA) is a potential result of the Class I G6PD variants. This comparative computational study attempted to correct the defect in variants structure by docking the AG1 molecule to selected Class I G6PD variants [G6PDNashville (Arg393His), G6PDAlhambra (Val394Leu), and G6PDDurham (Lys238Arg)] at the dimer interface and structural NADP+ binding site. It was followed by an analysis of the enzyme conformations before and after binding to the AG1 molecule using the molecular dynamics simulation (MDS) approach, while the severity of CNSHA was determined via root-mean-square deviation (RMSD), root-mean-square fluctuation (RMSF), hydrogen bonds, salt bridges, radius of gyration (Rg), solvent accessible surface area analysis (SASA), and principal component analysis (PCA). The results revealed that G6PDNashville (Arg393His) and G6PDDurham (Lys238Arg) had lost the direct contact with structural NADP+ and salt bridges at Glu419 - Arg427 and Glu206 - Lys407 were disrupted in all selected variants. Furthermore, the AG1 molecule re-stabilized the enzyme structure by restoring the missing interactions. Bioinformatics approaches were also used to conduct a detailed structural analysis of the G6PD enzyme at a molecular level to understand the implications of these variants toward enzyme function. Our findings suggest that despite the lack of treatment for G6PDD to date, AG1 remains a novel molecule that promotes activation in a variety of G6PD variants.

Targeted next-generation sequencing identifies eighteen novel mutations expanding the molecular and clinical spectrum of PKLR gene disorders in the Indian population.

Pyruvate kinase deficiency (PKD) is an autosomal recessive condition, caused due to homozygous or compound heterozygous mutation in the PKLR gene resulting in non-spherocytic hereditary hemolytic anemia. Clinical manifestations in PKD patients vary from moderate to severe lifelong hemolytic anemia either requiring neonatal exchange transfusion or blood transfusion support. Measuring PK enzyme activity is the gold standard approach for diagnosis but residual activity must be related to the increased reticulocyte count. The confirmatory diagnosis is provided by PKLR gene sequencing by conventional as well as targeted next-generation sequencing involving genes associated with enzymopathies, membranopathies, hemoglobinopathies, and bone marrow failure disorders. In this study, we report the mutational landscape of 45 unrelated PK deficiency cases from India. The genetic sequencing of PKLR revealed 40 variants comprising 34 Missense Mutations (MM), 2 Nonsense Mutations (NM), 1 Splice site, 1 Intronic, 1 Insertion, and 1 Large Base Deletion. The 17 novel variants identified in this study are A115E, R116P, A423G, K313I, E315G, E318K, L327P, M377L, A423E, R449G, H507Q, E538K, G563S, c.507 + 1 G > C, c.801_802 ins A (p.Asp268ArgfsTer48), IVS9dsA-T + 3, and one large base deletion. In combination with previous reports on PK deficiency, we suggest c.880G > A, c.943G > A, c.994G > A, c.1456C > T, c.1529G > A are the most frequently observed mutations in India. This study expands the phenotypic and molecular spectrum of PKLR gene disorders and also emphasizes the importance of combining both targeted next-generation sequencing with bioinformatics analysis and detailed clinical evaluation to elaborate a more accurate diagnosis and correct diagnosis for transfusion dependant hemolytic anemia in a cohort of the Indian population.

Screening of G6PD Deficiency in Newborns at a Tertiary Care Teaching Hospital in Assam, North East India: A Cross-sectional Study

Introduction: Glucose-6-Phosphate Dehydrogenase (G6PD) deficiency is the most frequently encountered enzymopathy in humans. It is closely linked to neonatal jaundice, chronic non-spherocytic haemolytic anaemia, and acute haemolytic anaemia. G6PD deficiency is a common cause of jaundice among neonates. Aim: To screen for G6PD deficiency among newborns at a tertiary care teaching centre in Assam. Materials and Methods: This hospital-based cross-sectional study was conducted in the postnatal ward of the Department of Paediatrics at Medical College & Hospital, Dibrugarh, Assam, India, from June 2021 to May 2022. A randomly selected sample of 630 term neonates aged between 24 hours and 7 days of life was included in the study. A 2ml blood sample was collected in an Ethylenediamine Tetra-acetic Acid (EDTA) vial from each neonate, and G6PD enzyme activity was estimated using the Kinetic Method with a commercially available G-six kit. Newborns with G6PD enzyme activity values less than 6.4 U/g Haemoglobin (Hb) were considered G6PD deficient. Data, including age, sex, religion, Total Serum Bilirubin (TSB/NBIL), G6PD activity, and Hb of the neonates, were entered into pre-designed forms. The data were analysed using the Chi-square test. Results: Among the 630 screened neonates, 48 were found to be G6PD deficient, of which the majority were males (34 males, 14 females), resulting in a male-to-female ratio of 2.4:1. The occurrence of G6PD deficiency was 7.62%. The mean G6PD enzyme activity in deficient neonates was 4.53±1.17 U/g Hb. Conclusion: This study identified a significant occurrence of G6PD deficiency in newborns, including females. The mean G6PD enzyme activity in deficient neonates was significantly lower than in normal cases.

Pyruvate kinase deficiency: A rare cause of hemolytic anemia: A case report from North-Eastern India

Pyruvate kinase, liver and RBC (PKLR) gene located on chromosome 1q21 encodes erythrocyte pyruvate kinase enzyme. Pyruvate kinase conveys the concluding tread of the glycolytic pathway, along with production of the 50% red cell total adenosine triphosphate. Pyruvate kinase deficiency (PKD) is a rare autosomal recessive disorder causing congenital non-spherocytic hemolytic anemia (CNSH). Biallelic pathogenic variation in the PKLR gene is responsible for PKD. It is the most common glycolytic defect resulting in CNSH. This case report highlights different pathogenic variants in PKLR gene detected in a patient having severe PKD.

An evaluation of mitapivat for the treatment of hemolytic anemia in adults with pyruvate kinase deficiency

Introduction Pyruvate kinase deficiency (PKD) is the most common cause of congenital nonspherocytic hemolytic anemia. Until recently, treatment had been limited to supportive management including red blood cell transfusions, splenectomy, and management of chronic disease complications such as iron overload and decreased bone mineral density. Areas covered We discuss preclinical data and phase 1, 2, and 3 clinical studies evaluating mitapivat for adult patients with hemolytic anemia secondary to PKD. Mitapivat has been shown to offer early and durable improvement in hemoglobin with reduction in transfusion burden, and preliminary data suggests it can induce a negative iron balance in many patients without the use of dedicated iron chelators. Expert opinion Mitapivat is a first-in-class allosteric activator of pyruvate kinase and the first FDA-approved disease directed therapy for PKD. It has a favorable safety profile and clear clinical efficacy. Given the considerable genetic heterogeneity of PKD and the rapid effect on improving hemoglobin and reducing hemolysis, a therapeutic trial of mitapivat should be considered in all patients with PKD who are not homozygous for the PKLR R479H mutation. Further investigations are needed regarding long-term safety and efficacy profiles and whether long-term PKD-associated complications can be reduced or even reversed.

Pyruvate kinase activator: A major breakthrough in the world of Hematology.

Pyruvate Kinase Deficiency (PKD) is a rare genetic disorder targeting Red Blood Cells that manifests as non-spherocytic hemolytic anemia. It has a global distribution with an unknown prevalence, and the frequently reported estimates for different geographical regions show a significant disparity. Because of its hereditary origin, treatment focuses on symptom relief and comfort (principally through blood transfusions, splenectomy, and folic acid supplementation). Pyrukynd (Mitavipat) is a new disease-modifying therapy that was just approved by the FDA and EHA based on clinical trial results that showed a big drop in the number of blood transfusions needed and a rise in hemoglobin levels. The drug stimulates cellular ATP synthesis by acting like Tyrosine Kinase Activator. Even though Pyrukynd has been the subject of studies and is approved for treatment, there is a lack of information on the effects of the medicine on nursing and pregnant mothers. The drug's administration and its effects on minors should also be pleaded.

Functional characterization of the p.(Gln195His) or Tainan and novel p.(Ser184Cys) or Toluca glucose-6-phosphate dehydrogenase (G6PD) gene natural variants identified through Mexican newborn screening for glucose-6-phosphate dehydrogenase deficiency

BackgroundNewborn screening for glucose-6-phosphate dehydrogenase deficiency (G6PDd) was implemented in Mexico beginning in 2017. In a Mexican population, genotyping analysis of G6PD as a second-tier method identified a previously unreported missense variant, p.(Ser184Cys), which we propose to call “Toluca”, and the extremely rare p.(Gln195His) or “Tainan” variant, which was previously described in the Taiwanese population as a Class II allele through in silico evaluations. Here, we sought to perform in vitro biochemical characterizations of the Toluca and Tainan G6PD natural variants and describe their associated phenotypes. MethodsThe “Toluca” and “Tainan” variants were identified in three unrelated G6PDd newborn males, two of whom lacked evidence of acute hemolytic anemia (AHA) or neonatal hyperbilirubinemia (NHB). We constructed wild-type (WT), Tainan, and Toluca G6PD recombinant enzymes and performed in vitro assessments. ResultsBoth variants had diminished G6PD expression, decreased affinities for glucose-6-phosphate and NADP+ substrates, significant decreases in catalytic efficiency (∼97 % with respect to WT-G6PD), and diminished thermostabilities that were partially rescued by NADP+. In silico protein modeling predicted that the variants would have destabilizing effects on the protein tertiary structure, potentially reducing the enzyme half-lives and/or catalytic efficiencies. ConclusionOur data suggest that G6PD “Tainan” and “Toluca” are potential Class II natural variants, which agrees with the absence of chronic nonspherocytic hemolytic anemia (CNSHA) in our patients. It remains to be determined whether these variants represent high-risk genetic factors for developing CNSHA, AHA, and/or NHB.

Hereditary nonspherocytic hemolytic anemia caused by glucose-6-phosphate isomerase (GPI) deficiency in a Chinese patient: a case report

BackgroundGlucose phosphate isomerase (GPI) deficiency is a rare autosomal recessive disorder that causes hereditary nonspherocytic hemolytic anemia (HNSHA). Homozygous or compound heterozygous mutation of the GPI gene on chromosome 19q13 is the cause of GPI deficiency. Fifty-seven GPI mutations have been reported at the molecular level.Case presentationA 5-month-old boy was presented with repeated episodes of jaundice after birth. He suffered from moderate hemolytic anemia (hemoglobin levels ranging from 62 to 91 g/L) associated with macrocytosis, reticulocytosis, neutropenia, and hyperbilirubinemia. Whole-exome sequencing showed that he has a missense mutation c.301G > A (p.Val101Met) in exon 4 and a frameshift mutation c.812delG (p.Gly271Glufs*131) in exon 10. Mutation p.Gly271Glufs*131 is a novel frameshift null mutation in GPI deficiency.ConclusionIn a patient with recurrent jaundice since birth, mutations in the GPI gene associated with HNSHA should be evaluated. The c.812delG (p.Gly271Glufs*131) variant may be a novel mutation of the GPI gene. Compound heterozygous mutations c.301G > A (p.Val101Met) and c.812delG (p.Gly271Glufs*131) are not relevant to neurological impairment.

Neonatal cholestasis – A case report on congenital bile acid synthetic defect type 4 and severe anemia

Congenital defects of bile acid synthesis are rare disorders that cause progressive liver dysfunction. We present a case of alpha methylacyl-CoA racemase (AMACR) deficiency with non-spherocytic hemolytic anemia who presented with rapidly progressive severe cholestasis and liver failure with normal gamma-glutamyl transferase levels. After extensive investigation, he was found to have AMACR deficiency with HBB gene mutation associated with non-spherocytic hemolytic anemia possibly explaining the severity of the disease. To the best of our knowledge, a similar association has not been reported so far.

P1735: IMPROVEMENTS IN PATIENT-REPORTED OUTCOMES IN MITAPIVAT-TREATED PATIENTS WITH PYRUVATE KINASE DEFICIENCY: A DESCRIPTIVE ANALYSIS FROM THE PHASE 3 ACTIVATE TRIAL

Background: Pyruvate kinase (PK) deficiency is a rare, inherited, non-spherocytic hemolytic anemia associated with acute and long-term complications, as well as a spectrum of signs and symptoms including jaundice, fatigue, and dyspnea. PK deficiency has a profound wide-ranging impact on health-related quality of life (HRQoL). Mitapivat (AG-348), a first-in-class, oral, allosteric activator of PK, was shown to improve hemoglobin (Hb), hemolysis, and hematopoiesis in a global, phase 3, randomized, placebo (PBO)-controlled trial evaluating mitapivat efficacy and safety in adults with PK deficiency who were not regularly transfused (ACTIVATE; NCT03548220). Furthermore, significant improvements in patient-reported outcomes (PROs) (measured by disease-specific PRO instruments: the PK deficiency diary [PKDD] and the PK deficiency impact assessment [PKDIA]) were demonstrated in patients (pts) receiving mitapivat compared with PBO. The PKDD is a self-administered, 7-item daily diary to assess the signs and symptoms of PK deficiency (including jaundice, tiredness, and shortness of breath), while the PKDIA is a 12-item weekly measure assessing the impacts of PK deficiency (pts rated the frequency of occurrence or difficulty of various activities). Aims: To describe PKDD and PKDIA outcomes for the subset of pts in the ACTIVATE trial who achieved the primary endpoint of Hb response, defined as a ≥1.5 g/dL increase in Hb from baseline (BL), sustained at ≥2 scheduled assessments at weeks (wks) 16, 20, and 24. Methods: Eighty pts were randomized 1:1 to receive mitapivat (5/20/50 mg twice daily) or PBO for 24 wks in the ACTIVATE trial. Change from BL to wk 24 in PKDD and PKDIA scores were prespecified secondary endpoints. For this post hoc analysis, changes from BL in PKDD weekly mean scores and PKDIA scores measured at scheduled visits (wks 4, 8, 12, 16, 20, and 24) were summarized for Hb responders, the overall mitapivat treatment arm, and PBO, using mean and 95% confidence intervals (CIs). For both the PKDD and the PKDIA, a lower score represents a lower disease burden. Results: In the ACTIVATE trial, 16/40 (40%) pts receiving mitapivat met the primary endpoint of Hb response compared with none for PBO (0/40; 0%). At wk 24, mean (95% CI) change from BL in PKDD weekly mean score was ‒7.12 (‒10.98, ‒3.27) for pts who achieved Hb response, ‒5.43 (‒7.47, ‒3.40) for the overall mitapivat treatment arm, and ‒1.86 (–4.04, 0.32) for the PBO arm (Figure 1a). At wk 24, mean (95% CI) change from BL in PKDIA score was ‒8.07 (‒11.05, ‒5.08) for pts who achieved Hb response, ‒4.82 (‒7.18, ‒2.46) for the overall mitapivat treatment arm, and ‒1.06 (‒3.70, 1.59) for the PBO arm (Figure 1b). Across both PRO instruments, improvements among mitapivat pts who achieved Hb response were sustained over time. Image:Summary/Conclusion: In the ACTIVATE trial, mitapivat-treated pts demonstrated significant improvements in signs, symptoms, and impacts based on PK deficiency-specific PRO instruments, compared with PBO. This analysis further reveals that improvements were greater in the subset of mitapivat-treated pts who achieved the primary endpoint. Together, these data indicate that mitapivat has the potential to improve HRQoL in pts with PK deficiency who are not regularly transfused.

Multicenter Study of Pyruvate Kinase Deficiency in Argentina

The red blood cell (RBC) pyruvate kinase deficiency (PKD) is the most common recessive congenital defect of glycolytic enzymes associated with non-spherocytic hemolytic anemia. It is a rare hereditary disorder caused by >300 variants in the PKLR gene. This is a retrospective study of 19 patients from different centers from Argentina with confirmed molecular diagnosis of PKD. Clinical follow-up was carried out from birth in most cases. Five consanguineous patients from “gypsy” community, were homozygous for the “PK-Gypsy deletion” (PK-Gd). During the neonatal period they developed anemia with icterus. Transfusion exchange was required in 60%, light therapy in 80%, and RBC transfusion in 80%. During the follow-up iron overload was detected in the 100%, cholecystectomy was indicated in 40%, and splenectomy in 60%. Thirteen cases had 2 missense variants (MS), being the Mediterranean variant (p.Arg486Trp) the more frequent detected (26%).Only 1 patient had a missense-splicing mutation combination. During the neonatal period, 86% had anemia and icterus. Light therapy was required in 78%, transfusion exchange in 21% and RBC transfusion in 64%. During the follow-up iron overload was detected in 57% and splenectomy was indicated in 43%. Transfusions (pre-splenectomy and post-splenectomy) were more required in PK-Gd cases as compared with patients with point mutations (100%/60% vs 71%/29% respectively). Our data indicates a high clinical-therapeutic-molecular heterogeneity in PKD patients with the PK-Gd group presenting the most severe cases.