Explore the vast range of titles available.

In this study, approximately half the patients with red-cell pyruvate kinase deficiency who were treated with mitapivat had an improvement in their hemoglobin level and decreased hemolysis that was sustained for nearly 3 years. Patients who had missense mutations that allowed for synthesis of a hypofunctioning enzyme were most likely to have a response.

Genetic variants of inosine triphosphatase (ITPA) that confer reduced ITPase activity are associated with protection against ribavirin(RBV)-induced hemolytic anemia in peginterferon(IFN)/RBV-based treatment of hepatitis C virus (HCV). Patients with reduced ITPase activity showed improved treatment efficacy when treated with IFN/RBV. In addition, a genetic polymorphism near the IL28B gene is associated with an improved response to IFN/RBV treatment. RBV has been an important component of IFN-containing regimens, and is currently recommended in combination with several IFN-free regimens for treatment of harder to cure HCV infections. To evaluate whether genetic variations that reduce ITPase activity impact RBV-induced anemia in IFN-free/RBV regimens. In this study, genetic analyses were conducted in the PEARL-IV trial to investigate the effect of activity-reducing ITPA variants as well as IL28B polymorphism on anemia, platelet (PLT) counts, and virologic response in HCV genotype1a-infected patients treated with the direct-acting antiviral (DAA) regimen of ombitasvir/paritaprevir/ritonavir and dasabuvir±RBV. Reduction in ITPase activity and homozygosity for the IL28Brs12979860 CC genotype protected against RBV-induced anemia. In patients receiving RBV, reduced ITPase activity was associated with reduced plasma RBV concentration and higher PLT counts. ITPase activity had no impact on response to DAA treatment, viral kinetics, or baseline IP-10 levels. Our study demonstrates that genetics of ITPA and IL28B may help identify patients protected from RBV-induced anemia when treated with IFN-free regimens. Our work demonstrates for the first time that IL28B genetics may also have an impact on RBV-induced anemia. This may be of particular significance in patients with difficult-to-cure HCV infections, such as patients with decompensated cirrhosis where RBV-containing regimens likely will continue to be recommended.

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.

Background: After ruling out the most common causes of severe hemolytic anemia by routine diagnostic tests, certain patients remain without a diagnosis. The aim of this study was to elucidate the genetic cause of the disease in these patients using next generation sequencing (NGS). Methods: Four unrelated Iranian families including six blood transfusion dependent cases and their parents were referred to us from a specialist center in Tehran. There was no previous history of anemia in the families and the parents had no abnormal hematological presentations. All probands presented severe congenital hemolytic anemia, neonatal jaundice and splenomegaly. Common causes of hemolytic anemia were ruled out prior to this investigation in these patients and they had no diagnosis. Whole exome sequencing (WES) was performed in the probands and the results were confirmed by Sanger sequencing and subsequent family studies. Results: We identified five variants in the PKLR gene, including a novel unpublished frameshift in these families. These variants were predicted as pathogenic according to the ACMG guidelines by Intervar and/or Varsome prediction tools. Subsequent family studies by Sanger sequencing supported the diagnosis of pyruvate kinase deficiency (PKD) in six affected individuals and the carrier status of disease in their parents. Conclusion: These findings show that PKD is among the rare blood disorders that could remain undiagnosed or even ruled out in Iranian population without performing NGS. This could be due to pitfalls in clinical, hematological or biochemical approaches in diagnosing PKD. Furthermore, genotyping PKD patients in Iran could reveal novel mutations in the PKLR gene.

Most patients with anemia are diagnosed through clinical phenotype and basic laboratory testing. Nonetheless, in cases of rare congenital anemias, some patients remain undiagnosed despite undergoing an exhaustive workup. Genetic testing is complicated by the large number of genes that are involved in rare anemias, due to similarities in the clinical presentation. We sought to enhance the diagnosis of patients with congenital anemias by using targeted next-generation sequencing. The genetic diagnosis was performed by gene capture followed by next-generation sequencing of 76 genes known to cause anemia syndromes. Genetic diagnosis was achieved in 17 of 21 transfusion-dependent patients and undiagnosed by conventional workup. Four cases were diagnosed with red cell membrane protein defects, four patients were diagnosed with pyruvate kinase deficiency, one case of adenylate kinase deficiency, one case of glucose phosphate isomerase deficiency, one case of hereditary xerocytosis, three cases having combined membrane and enzyme defect, two cases with Diamond–Blackfan anemia (DBA) and 1 with CDA type II with 26 different mutations, of which 21 are novel. Earlier incorporation of this NGS method into the workup of patients with congenital anemia may improve patient care and enable genetic counselling.

ObjectiveGlucose-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.MethodsThe 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.ResultsBy 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.ConclusionEarly 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.

Hereditary xerocytosis (HX) or dehydrated hereditary stomatocytosis (DHS) [OMIM 194380], in which PIEZO1 gene mutation has recently been identified, is difficult to diagnose. We report here the discovery of a PIEZO1 gene mutation in a Japanese family (father, daughter, and son) who were previously diagnosed with hereditary high phosphatidylcholine hemolytic anemia (HPCHA). All of the affected family members had non-spherocytic hemolytic anemia associated with severe hemochromatosis-related diabetes mellitus. Although the causative correlation between HPCHA and PIEZO1-gene mutated HX/DHS remains to be clarified, our findings raise an important question as to whether any of the HPCHA cases previously diagnosed in Japan may have in fact been the form of hemolytic anemia known as HX/DHS with PIEZO1 gene mutation.

A basic leucine zipper transcription factor, NF-E2-related factor 2 (Nrf2), plays a critical role in the cellular defense mechanism by mediating a coordinate up-regulation of antioxidant responsive element-driven detoxification and antioxidant genes. Here, we report that targeted disruption of Nrf2 causes regenerative immune-mediated hemolytic anemia due to increased sequestration of damaged erythrocytes. Splenomegaly and spleen toxicity in Nrf2-/-mice raised a possibility of hemolytic anemia and splenic extramedullary hematopoiesis in Nrf2-/-mice. In support of this, hematology analysis revealed that Nrf2-/-mice suffer from anemia with abnormal red cell morphologies (i.e., Howell-Jolly bodies, acantocytes, and schistocytes). In addition, Nrf2-/-erythrocytes were more sensitive to H2O2-induced hemolysis, and erythrocytebound IgG levels were markedly increased in Nrf2-/-mice compared with Nrf2+/+mice. Because IgG bound to erythrocytes in the presence of oxidative damage in erythrocytes (regardless of Nrf2 genotype), these data support that Nrf2-/-erythrocytes have higher levels of damage compared with Nrf2+/+cells. Finally, Nrf2-/-mice showed increased levels of erythrocyte-bound IgG compared with Nrf2+/+mice after H2O2injection in vivo, suggesting that the decreased glutathione and increased H2O2render the Nrf2-/-mice more susceptible to toxicity. Taken together, these observations indicate that a chronic increase in oxidative stress due to decreased antioxidant capacity sensitizes erythrocytes and causes hemolytic anemia in Nrf2-/-mice, suggesting a pivotal role of Nrf2- antioxidant responsive element pathway in the cellular antioxidant defense system.

Protection against anaemia due to hepatitis C treatments The standard treatment for chronic hepatitis C infection, pegylated interferon (pegIFN) and ribavirin (RBV), carries a range of unpleasant side effects including haemolytic anaemia. Now a genome-wide association study using DNA samples from more than a thousand hepatitis C patients reveals that that genetic variants that lead to inosine triphosphatase deficiency are protective against ribovario-induced haemolytic anaemia. Because inosine triphosphatase deficiency seems to be a benign condition, therapies that target this enzyme could help protect against RBV-induced anaemia. And testing patients for the deficiency could help identify those at risk from this particular side effect. Worldwide, 170 million people are infected with the hepatitis C virus, which is a significant cause of liver-related illnesses and deaths. Standard treatment combines pegylated interferon alpha and ribavirin (RBV), but has some negative effects, notably RBV-induced haemolytic anaemia. Here, a genome-wide study shows that a deficiency in the enzyme inosine triphosphatase protects against haemolytic anaemia in patients receiving RBV. Chronic infection with the hepatitis C virus (HCV) affects 170 million people worldwide and is an important cause of liver-related morbidity and mortality 1 . The standard of care therapy combines pegylated interferon (pegIFN) alpha and ribavirin (RBV), and is associated with a range of treatment-limiting adverse effects 2 . One of the most important of these is RBV-induced haemolytic anaemia, which affects most patients and is severe enough to require dose modification in up to 15% of patients. Here we show that genetic variants leading to inosine triphosphatase deficiency, a condition not thought to be clinically important, protect against haemolytic anaemia in hepatitis-C-infected patients receiving RBV.

Familial xerocytosis (HX) in humans is an autosomal disease that causes dehydration of red blood cells resulting in hemolytic anemia which has been traced to two individual mutations in the mechanosensitive ion channel, PIEZO1. Each mutation alters channel kinetics in ways that can explain the clinical presentation. Both mutations slowed inactivation and introduced a pronounced latency for activation. A conservative substitution of lysine for arginine (R2456K) eliminated inactivation and also slowed deactivation, indicating that this mutant’s loss of charge is not responsible for HX. Fitting the current vs. pressure data to Boltzmann distributions showed that the half-activation pressure, P ₁/₂, for M2225R was similar to that of WT, whereas mutations at position 2456 were left shifted. The absolute stress sensitivity was calibrated by cotransfection and comparison with MscL, a well-characterized mechanosensitive channel from bacteria that is driven by bilayer tension. The slope sensitivity of WT and mutant human PIEZO1 (hPIEZO1) was similar to that of MscL implying that the in-plane area increased markedly, by ∼6–20 nm ² during opening. In addition to the behavior of individual channels, groups of hPIEZO1 channels could undergo simultaneous changes in kinetics including a loss of inactivation and a long (∼200 ms), silent latency for activation. These observations suggest that hPIEZO1 exists in spatial domains whose global properties can modify channel gating. The mutations that create HX affect cation fluxes in two ways: slow inactivation increases the cation flux, and the latency decreases it. These data provide a direct link between pathology and mechanosensitive channel dysfunction in nonsensory cells.