Congenital Nonspherocytic Hemolytic Anemia Research Articles

Clinico-mutational profile and the impact of splenectomy in children with glucose-6-phosphate isomerase deficiency

BackgroundThere is a lack of literature on the role of splenectomy in hemolytic anemias due to glucose-6-phosphate isomerase (GPI) deficiency. GPI deficiency is a rare red blood cell (RBC) enzymopathy of the glycolytic pathway. Most present with severe disease requiring frequent transfusions. In this study, we report the effect of splenectomy in the world's largest cohort of GPI deficiency patients. The study aimed to describe the clinical, mutational, and laboratory parameters of patients with GPI deficiency. A comparison of the transfusion requirement pre- and post-splenectomy is also included. Material and methodsThe ambispective study was performed from 2017 to 2023. Patients with congenital non-spherocytic hemolytic anemia (CNSHA) were screened for GPI deficiency. Detailed history, including demographic, clinical data, and transfusion details, were noted. Hematological parameters and RBC enzyme activity were estimated using spectrophotometry. The genetic study was done using restriction fragment length polymorphism, and confirmation was obtained through Sanger's sequencing. Patients were followed up after splenectomy. ResultsEighteen patients were diagnosed with GPI deficiency. About 3/4th (14/18; 77.7 %) had significant hepatosplenomegaly. Median serum ferritin levels were 890 ng/ml. Seven patients were on oral iron chelation. The nutritional status assessed as per the Indian Academy of Pediatrics growth charts revealed significant growth retardation. All the patients had severe anemia (mean Hb: 6.4 g/dl) and macrocytosis (mean MCV: 129.2 fl). Laboratory features of hemolysis were evident with reticulocytosis, raised serum lactate dehydrogenase, and indirect bilirubin. The mean GPI enzyme activity was 28.75 IU/g Hb.Ten (55.5 %) patients underwent splenectomy at a median age of 7 years. Five remain transfusion-free post-splenectomy at a median follow-up of 54 months. Other 5 had a significant reduction in transfusion requirement post-splenectomy (p < 0.05). Post-splenectomy, the mean hemoglobin levels increased from 6.2 to 8.1 gm%, and the mean reticulocyte counts reduced from 7.4 % to 4.8 %. Fifteen of 18 had the pathogenic c.1040G > A(p.Arg347His) homozygous mutation. ConclusionThe study demonstrates the benefit of splenectomy in patients with GPI deficiency.

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.

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.

Clinical, laboratory, and mutational profile of children with glucose phosphate isomerase deficiency: a single centre report.

Glucose phosphate isomerase (GPI) deficiency is an autosomal recessive condition with mutations in the GPI gene on chromosome 19q13.1. Patients present with congenital non-spherocytic hemolytic anemia, and occasionally intellectual disability. In this study, we describe the clinical, hematological and biochemical parameters in the largest single-center cohort consisting of 17 GPI-deficient cases. Demographic and clinical data were noted, and red cell enzyme activity levels were estimated. Mutation analysis was done by single-stranded-conformation polymorphism, restriction-fragment length polymorphism and Sanger's sequencing of exon 12 of the GPI gene. The male-to-female ratio was 0.7:1, median age at diagnosis was 5.0years, 82.3% of patients had severe neonatal jaundice, and 13.3% had subtle neurological manifestations. Median Hb and MCV levels were 6.3g/dl and 130.2fl. Splenectomized patients required fewer transfusions. Sixteen of 17 patients had the pathogenic c.1040G > A (p.Arg347His) homozygous mutation in exon12 of the GPI gene, and one had the pathogenic c.1414C > T(p.Arg472Cys) homozygous mutation in exon 16. In summary, we report that neonatal jaundice, macrocytosis and high prevalence of p.Arg347His variant were predominant in GPI deficiency with prominent lack of neurological manifestations, and we emphasize the benefits of splenectomy and the need for genetic counseling.

NEW REPORT OF KOLN HEMOGLOBIN FROM COUNTRYSIDE/INTERIOR OF SÃO PAULO

Hemoglobinopathies are considered a major public health problem in many countries, including Brazil, a fact explained by their frequency, genetic diversity and clinical importance. The unstable hemoglobin group is associated with congenital non-spherocytic hemolytic anemia due to instability of the hemoglobin molecule which can lead to the formation of characteristic inclusion bodies or Heinz bodies. Hb Köln beta 98(FG5) Val>Met is the result of the substitution of the amino acid valine for methionine at position 98 of the Beta chain of hemoglobin. Hemoglobin Köln reports are concentrated in Europe and in some parts of the Orient, such as northern Europe, among Jews, Czechoslovaks, Japanese, and also Koreans. A case was recently reported in India and, in Brazil, some cases have been known since 1993. This hemoglobinopathy is widely distributed, however, its frequency is extremely low when compared to the most frequent variants such as hemoglobin S (HbS) and C (HbC) in Brazil. Patients with Hb Köln usually present with mild hemolytic anemia characterized by reticulocytosis, splenomegaly and bilirubin, jaundice, and persistent dark urine excretion. In addition, some case reports describe Köln patients with priapism or persistent thrombocytopenia. We report a case of Köln's Hemoglobin in a 54-year-old female patient with hemolytic anemia under investigation. Osmotic instability tests were performed with a NaCl solution, hemoglobin electrophoresis in cellulose acetate at alkaline pH in which the presence of a band migrating between A 2 and S hemoglobins was observed, when the hemolysate was performed with 1% saponin, search for Heinz bodies with a 1:1 brilliant cresyl blue solution incubated at 37°C for 30 minutes, after which the bodies were identified in the blood smear. Upon suspicion of unstable hemoglobin, other standard laboratory procedures were performed, such as High Performance Liquid Chromatography (HPLC) with the Trinity®Premier Resolution Analytical Column equipment, in which a dosage of 3.18% HbA 2 and 0.16% HbF was observed. The results corroborate the electrophoretic and chromatographic profile suggestive of heterozygosity for Hb Köln. It is known today that there are 155 unstable hemoglobins identified worldwide and, of these, approximately 102 lead to hemolysis or abnormal oxygen affinity. In contrast the other variants do not show hematological abnormalities, but show instability in in vitro test. The phenotype of unstable variants of hemoglobin is diverse and dependent on the position of the mutation, which can lead to changes in the structure of the globin chain or of the hemoglobin molecule. Hb Köln is the most common of the unstable variants of hemoglobin and was first described by Pribilla in 1962. One of the main characteristics of unstable hemoglobins is the presence of Heinz bodies, which was curiously observed in this patient's red blood cells, corroborating data already described in the literature. Thus, a reliable detection of Hb Köln together with genetic counseling and prenatal diagnosis are essential to improve the well-being of patients.

Health-related quality of life and fatigue in children and adults with pyruvate kinase deficiency

AbstractPyruvate kinase deficiency (PKD) is the most common cause of congenital nonspherocytic hemolytic anemia. Although recognition of the disease spectrum has recently expanded, data describing its impact on health-related quality of life (HRQoL) are limited. In this prospective international cohort of 254 patients (131 adults and 123 children) with PKD, we used validated measures to assess the impact of disease on HRQoL (EuroQol 5-Dimension Questionnaire, Pediatric Quality of Life Inventory Generic Core Scale version 4.0, and Functional Assessment of Cancer Therapy-Anemia) and fatigue (Patient Reported Outcomes Measurement Information System Fatigue and Pediatric Functional Assessment of Chronic Illness Therapy-Fatigue). Significant variability in HRQoL and fatigue was reported for adults and children, although individual scores were stable over a 2-year interval. Although adults who were regularly transfused reported worse HRQoL and fatigue compared with those who were not (EuroQol-visual analog scale, 58 vs 80; P = .01), this difference was not seen in children. Regularly transfused adults reported lower physical, emotional, and functional well-being and more anemia symptoms. HRQoL and fatigue significantly differed in children by genotype, with the worst scores in those with 2 severe PKLR mutations; this difference was not seen in adults. However, iron chelation was associated with significantly worse HRQoL scores in children and adults. Pulmonary hypertension was also associated with significantly worse HRQoL. Additionally, 59% of adults and 35% of children reported that their jaundice upset them, identifying this as an important symptom for consideration. Although current treatments for PKD are limited to supportive care, new therapies are in clinical trials. Understanding the impact of PKD on HRQoL is important to assess the utility of these treatments. This trial was registered at www.clinicaltrials.gov as #NCT02053480.

Rare hereditary nonspherocytic hemolytic anemia caused by a novel homozygous mutation, c.301C\u2009>\u2009A, (Q101K), in the AK1 gene in an Indian family

BackgroundAdenylate kinase (AK) deficiency is a rare red cell enzymopathy associated with moderate to severe congenital nonspherocytic hemolytic anemia, along with mental and psychomotor retardation (in exceptional cases). Only ten mutations have been detected in the AK1 gene to date. In this study, we aimed to diagnose the unexplained issue of haemolytic anaemia and offer antenatal screening to the family.MethodsGenomic DNA was isolated from whole blood by a standard protocol. Targeted next-generation sequencing (t-NGS) was performed to identify pathogenic variants in the patient and control samples. A chronic villus sample was collected at 11 weeks of gestation from the mother, and molecular testing was performed. Genetic confirmation was concluded by Sanger DNA sequencing. Bioinformatics tools predicted the pathogenicity of the variant.Resultst-NGS revealed a homozygous variant (c.301C > A, p. Gln101Lys) in the AK1 gene in the patient and heterozygosity in the fetus and parental samples. The prediction tools SIFT, Polyphen2, Provean, PMUT, Mutation taster, and Mutation Assessor, confirmed the damaging effect of the variant on the AK1 protein structureConclusionWe have presented a novel mutation in the AK1 gene (p. Gln101Lys) associated with adenylate kinase deficiency. It is the first prenatal diagnosis of AK deficiency in India, where heterogeneity is exceptionally high.

A Sri Lankan girl with a new genetic variant in the PKLR gene causing pyruvate kinase deficiency: a case report

BackgroundErythrocyte pyruvate kinase is expressed under the control of the PKLR gene located on chromosome 1q21. Pyruvate kinase catalyzes the final steps of the glycolytic pathway and creates 50% of the red cell total adenosine triphosphate. Pyruvate kinase deficiency is the commonest glycolytic defect causing congenital non-spherocytic hemolytic anemia inherited in an autosomal recessive trait in which homozygotes and compound heterozygotes are common. Over 200 mutations have been described in patients with pyruvate kinase deficiency. This case report identifies a new pathogenic variant in PKLR gene detected in a patient with severe pyruvate kinase deficiency.Case presentationA Sri Lankan Sinhalese girl who developed neonatal anemia and jaundice within 24 hours of birth with mild hepatomegaly. She was from a nonconsanguineous marriage and had two siblings who had no hematological disorders. She had repeated admissions due to similar illnesses and at the age of 8 years was found to have pyruvate kinase deficiency associated with a novel homozygous pathogenic variant c.507+1delG in the PKLR gene.ConclusionsA novel genetic variant in PKLR gene, consistent with pyruvate kinase deficiency, was detected in a Sri Lankan girl. This genetic variant may be specific to the Asian population and requires further studies.

A Family Affected by a Life-Threatening Erythrocyte Defect Caused by Pyruvate Kinase Deficiency With Normal Iron Status: A Case Report.

BackgroundRed cell pyruvate kinase deficiency (PKD) is a defect of glycolysis causing congenital non-spherocytic hemolytic anemia. PKD is transmitted as an autosomal recessive trait. The clinical features of PKD are highly variable, from mild to life-threatening anemia which can lead to death in the neonatal period. Most patients with PKD must receive regular transfusions in early childhood and as a consequence suffer from iron overloading.PatientHere, we report a Polish family with life-threatening hemolytic anemia of unknown etiology. Whole exome sequencing identified two heterozygous mutations, c.1529 G > A (p.R510Q) and c.1495 T > C (p.S499P) in the PKLR gene. Molecular modeling showed that the both PKLR mutations are responsible for major disturbance of the protein structure and functioning. Despite frequent transfusions the patients do not show any signs of iron overload and hepcidin, a major regulator of iron uptake, is undetectable in their serum. The patients were homozygous for the rs855791 variant of the TMPRSS6 gene which has earlier been shown to down-regulate iron absorption and accumulation.ConclusionThe lack of iron overload despite a reduced level of hepcidin in two transfusion-dependent PKD patients suggests the existence of a hepcidin-independent mechanism of iron regulation preventing iron overloading.

Pyruvate kinase deficiency: epidemiology, molecular analyses and modern diagnostic approaches (literature review)

Red cell pyruvate kinase deficiency is the most common glycolytic defect causing congenital nonspherocytic hemolytic anemia. Pyruvate kinase is the enzyme involved in the last step of glycolysis – the transfer of a phosphate group from phosphoenolpyruvate producing the enolate of pyruvate and ATP (50 % of total energy ATP of erythrocytes). ATP deficiency directly shortened red cell lifespan. Affected red blood cells are destroyed in the splenic capillaries, leading to the development of chronic hemolytic anemia. It is an autosomal recessive disease, caused by homozygous and compound heterozygous mutations in the PKLR gene. There are no exact data on the incidence of pyruvate kinase deficiency, but the estimated frequency varies from 3: 1,000,000 to 1:20,000. The clinical features of the disease and the severity are highly variable. Diagnosis of pyruvate kinase deficiency is based on the determination of pyruvate kinase activity and molecular genetic study of the PKLR gene. The variety of clinical manifestations, possible complications, as well as the inaccessibility of diagnostic methods complicate the diagnosis.

Molecular heterogeneity of pyruvate kinase deficiency.

Red cell pyruvate kinase (PK) deficiency is the most common glycolytic defect associated with congenital non-spherocytic hemolytic anemia. The disease, transmitted as an autosomal recessive trait, is caused by mutations in the PKLR gene and is characterized by molecular and clinical heterogeneity; anemia ranges from mild or fully compensated hemolysis to life-threatening forms necessitating neonatal exchange transfusions and/or subsequent regular transfusion support; complications include gallstones, pulmonary hypertension, extramedullary hematopoiesis and iron overload. Since identification of the first pathogenic variants responsible for PK deficiency in 1991, more than 300 different variants have been reported, and the study of molecular mechanisms and the existence of genotype-phenotype correlations have been investigated in-depth. In recent years, during which progress in genetic analysis, next-generation sequencing technologies and personalized medicine have opened up important landscapes for diagnosis and study of molecular mechanisms of congenital hemolytic anemias, genotyping has become a prerequisite for accessing new treatments and for evaluating disease state and progression. This review examines the extensive molecular heterogeneity of PK deficiency, focusing on the diagnostic impact of genotypes and new acquisitions on pathogenic non-canonical variants. The recent progress and the weakness in understanding the genotype-phenotype correlation, and its practical usefulness in light of new therapeutic opportunities for PK deficiency are also discussed.

Congenital Nonspherocytic Hemolytic Anemia Caused by Krüppel-Like Factor 1 Gene Variants: Another Case Report

In this study, we report on a compound heterozygote for variants in the key erythroid transcription factor Krüppel-like factor 1 (KLF1) gene in a patient who presented with severe, transfusion-dependent hemolytic anemia. The red cells were normochromic and normocytic, and resembled those seen in patients with congenital nonspherocytic hemolytic anemia (CNSHA). Next generation sequencing (NGS) revealed that the patient was a compound heterozygote for the KLF1 frameshift variant c.519_525dup (p.Gly176ArgfsTer179) and a missense variant c.1012C>A (p.Pro338Thr). This report adds to the wide clinical spectrum of KLF1 gene variants. We suggest that loss of KLF1 should be considered in otherwise unexplained cases of congenital hemolytic anemia.

Whole Exome Sequencing Identifies a Novel Variant in the Pklr Gene Which Worsen the Anemia Status in a Congenital Dyserthropoietic Anemia Patient

Congenital dyserythropoietic anemia (CDAs) is a group of hereditary disorders characterized by ineffective erythropoiesis and distinct morphological abnormalities of erythroblasts in the bone marrow. Diagnosis of CDA is based primarily on the morphology of bone marrow erythroblasts but genetic tests might have more and more important roles recently. Here, we describe a 31-year old female with atypical CDA under regular blood transfusions. The results of blood tests were as followed: RBC: 3080000/µL, Hb: 9.9 g/dL, Hct: 26.8%, MCV: 87.0 fl, MCH:32.2 pg, and MCHC: 36.9 g/L. In this study, analysis of CDA-related genes, including SEC23B, CDAN1, KLF1, and C15orf41, were analyzed by exome sequencing but no pathogenic variant was found. In additional, we analyzed RBC-related genes and a novel variant in the PKLR p.A468G (NP_000289) was found which was also confirmed by Sanger sequence. Variant of PKLR gene has been reported as the cause of pyruvate kinase (PK) deficiency anemia. PK deficiency is the most cause of congenital nonspherocytic hemolytic anemia with GMAF (global minor allele frequency) of 0.0001. The clinical features of PK-deficient patients are highly variable degree of chronic hemolysis with severe neonatal jaundice and fetal anemia at birth. In this case, PKLR p.A468G heterozygous variant was detected in a patient with PK deficiency, as an example of precision diagnosis by exome sequencing. DisclosuresNo relevant conflicts of interest to declare.

Clinical spectrum of pyruvate kinase deficiency: data from the Pyruvate Kinase Deficiency Natural History Study

AbstractAn international, multicenter registry was established to collect retrospective and prospective clinical data on patients with pyruvate kinase (PK) deficiency, the most common glycolytic defect causing congenital nonspherocytic hemolytic anemia. Medical history and laboratory and radiologic data were retrospectively collected at enrollment for 254 patients with molecularly confirmed PK deficiency. Perinatal complications were common, including anemia that required transfusions, hyperbilirubinemia, hydrops, and prematurity. Nearly all newborns were treated with phototherapy (93%), and many were treated with exchange transfusions (46%). Children age 5 years and younger were often transfused until splenectomy. Splenectomy (150 [59%] of 254 patients) was associated with a median increase in hemoglobin of 1.6 g/dL and a decreased transfusion burden in 90% of patients. Predictors of a response to splenectomy included higher presplenectomy hemoglobin (P = .007), lower indirect bilirubin (P = .005), and missense PKLR mutations (P = .0017). Postsplenectomy thrombosis was reported in 11% of patients. The most frequent complications included iron overload (48%) and gallstones (45%), but other complications such as aplastic crises, osteopenia/bone fragility, extramedullary hematopoiesis, postsplenectomy sepsis, pulmonary hypertension, and leg ulcers were not uncommon. Overall, 87 (34%) of 254 patients had both a splenectomy and cholecystectomy. In those who had a splenectomy without simultaneous cholecystectomy, 48% later required a cholecystectomy. Although the risk of complications increases with severity of anemia and a genotype-phenotype relationship was observed, complications were common in all patients with PK deficiency. Diagnostic testing for PK deficiency should be considered in patients with apparent congenital hemolytic anemia and close monitoring for iron overload, gallstones, and other complications is needed regardless of baseline hemoglobin. This trial was registered at www.clinicaltrials.gov as #NCT02053480.

Mutations in the Second Linker of KLF1 Cause Congenital Non-Spherocytic Hemolytic Anemia Due to Global Reduction of In Vivo DNA-Binding Affinity

The mommeD45 mutation generates an amino acid transversion (H350R) within a conserved linker peptide between zinc fingers two and three of Klf1 (linker 2). Klf1H350R/H350R mice have mild compensated microcytic anaemia 1. Mice Carrying the H350R mutation were interbred with Klf1+/- mice. Klf1H350R/-mice have severe perinatal haemolytic anaemia, jaundice and marked splenomegaly. Haematological evaluation of these mice shows similar phenotypes to human patients who are compound heterozygotes for null and linker 2 mutations in KLF12. Analysis of Klf1H350R/- fetal liver by flow cytometry showed an increase in circulating immature CD71+ Ter119+ erythroblasts. In the bone marrow, a marked reduction in mature (Cd71- Ter119+) red blood cells was observed. Flow cytometric analysis of the spleen from Klf1H350R/- animals revealed an expansion of erythroid cells consistent with extramedullary erythropoiesis. ChIP-seq for Klf1 in 14.5DPC fetal liver from Klf1H350R/H350R mice revealed no loss in specificity when compared to wildtype Klf1, but a global reduction in affinity. Affinity measurements of recombinant zinc finger domains in vitro will be presented. By RNA-seq, we observed significantly lower expression of Klf1 target genes in mice homozygous for the H350R mutation compared to mice carrying a wildtype allele. And this correlates with reduced DNA binding observed in ChIP-seq and in vitro assays. Previous studies of the linkers in C2H2 zinc finger transcription factors have revealed their necessity as structural and regulatory components for the C2H2 class of transcription factors. Our results show the second linker of Klf1 plays an indirect role in DNA-binding and does not act just as a spacer for the zinc fingers.

ATP11C Encodes a Major Flippase in Human Erythrocyte and Its Genetic Defect Causes Congenital Non-Spherocytic Hemolytic Anemia

Flippases are members of the P-IV ATPase family of proteins, and contribute to localization of phosphatidylserine (PS) in inner leaflet by its ATP-dependent active transport from outer to inner leaflet of lipid bilayer of erythrocyte membranes. It is critical that erythrocytes maintain PS in the inner monolayer to ensure their 120-day survival in circulation since externalization of PS will be recognized as an eat-me signal, resulting in phagocytosis by splenic macrophages. In the present study, we identified that ATP11C gene encodes a major flippase in human erythrocytes. A 13 years-old boy was referred to our hospital for consultation for work up of an undiagnosed congenital hemolytic anemia. Since extensive biochemical and molecular analysis failed to identify hemoglobin, erythrocyte membranes and enzyme abnormalities for the pathogenesis of hemolysis, we performed the whole exome analysis by massively parallel sequencing. We identified that the proband is hemizyogous, and the mother is heterozygous for a missense mutation of ATP11C, c.1253C>A, corresponding to a single amino acid substitution, p.Thr418Asn. Flipping activity as measured by PS internalization was decreased to 10% in the red cells of the proband compared to a normal control, clearly demonstrating that ATP11C encodes a major flippase in the human erythrocyte membranes. The PS-positive erythrocytes were not significantly increased in the whole blood but only in the most dense senescent cells, suggesting that PS exposure did not occur until very late stages of lifespan. We showed that PS exposure mediated by Ca2+-stimulated phospholipid scrambling was not different between red cells of the proband and control. Taken together, our findings imply that suppressed scrambling activity rather than flippase activity is the major contributor to maintainance of PS in inner leaflet of normal red cells during their 120-day lifespan, and that PS exposure to cell surface as an 'eat-me' signal depends primarily on scramblase activity at the end of lifespan. Importantly, our study has enables us to identify the major flippase of human erythrocyte membrane. DisclosuresNo relevant conflicts of interest to declare.

A Comprehensive Next Generation Sequencing Gene Panel Focused on Unexplained Anemia

Congenital anemia is difficult to diagnose once common causes have been excluded; for example 80% cases of congenital non-spherocytic hemolytic anemia are undiagnosed once pyruvate kinase and G6PD deficiencies have been excluded using phenotypic analysis. We describe a next generation sequencing strategy, targeting 147 genes, to facilitate the diagnosis of these conditions. The coding regions, splice sites and 200 bp into the untranslated regions were examined in each gene. All clinically significant variants were confirmed by Sanger sequencing, including confirmation in any appropriate family members.Illumina MiSeq data was analysed using a bespoke bioinformatics pipeline, which has been validated to a UK certified standard. The pipeline implements detection of genetic variants using multiple base callers and discovery of copy number variants based on sequencing depth. Variants are annotated with information from ClinVar, and population frequency data from ExAC and 1000 genomes project. All genes are sequenced in every individual but data analysis can easily be restricted to virtual subpanels, excluding analysis of genes not requested. Here we present three cases, highlighting the diagnostic utility of the panel as well as the underlying bioinformatics analysis.Case 1. A male Caucasian child of <1 year, presented with haemolysis (LDH 539 IU/L, total bilirubin 39 umol/L), haematology (Hb 92g/L, MCV 84.4, MCH 28.9, absolute retic count 313.8x109/L); his film showed marked anisopoikilocytes, microspherocytes and polychromasia. He had frontal bossing and a palpable spleen and had suffered several infections, the child was transfused once. His father's film showed elliptocytes, FBC (Hb 127g/L, MCV 89.6, MCH 30.6, absolute retic count 230.5x109/L) but he had never been transfused. The mother's FBC was normal (Hb 113g/L, MCV 87.0, MCH 29.2, absolute retic count 48.4x109/L) but her film also showed elliptocytes. Analysis using the red cell panel found the child to be compound heterozygous for c.83G>A; p.Arg28His and c.[5572C>G; 6531-12C>T]; p.[Leu1858Val;?] in the SPTA1 gene, suggesting the diagnosis of hereditary pyropoikilocytosis. The c.83G>A; p.Arg28His mutation was inherited from the father and the c.[5572C>G; 6531-12C>T]; p.[Leu1858Val;?] low expression allele was inherited from the mother, who was homozygous.Case 2. The post mortem report from a hydropic still birth (36/40) showed extensive extramedullary hematopoiesis and severe anemia. A DNA sample was sent to the laboratory accompanied by blood samples from both parents whose hematology was normal. The DNA sample from the proband was relatively small so only the parental samples were analyzed using the red cell panel. Sequence analysis identified the mother to carry the c.3173dupG; p.Gln1659fs pathogenic variant and the father carried the c.2867_2868+1dupCCG pathogenic variant in the CDAN1 gene. Sanger Sequencing showed that the child had inherited both mutations from the parents. Variants in CDAN1 are associated with CDA type 1 which is documented to be a rare form of anemia which can be lethal.Case 3. An Italian girl carrying a paternally inherited c.118C>T β0 thalassemia variant presented with a severe form of microcytic anemia (FBC, Hb 86g/L, RBC 4.87 x1012/L, MCV 55.2, MCH 17.7 and HbA2=5%). The severity of her anemia (not transfused) and palpable spleen suggested she had an additional pathogenic variant that had not been identified. Her mother had normal hematology FBC, Hb 133g/L, RBC 4.82x1012/L, MCV 79.9, MCH 27.6. After sequencing, Exome Depth analysis of the proband's LCR identified a novel deletion which removed the 5' HS1 and HS2 sites but left HS3-5 intact (confirmed by MLPA in the mother and proband). The combination of this mild down regulation of the beta globin locus in combination with the c.118C>T β0 thalassemia variant caused her phenotype to be more severe than just a beta thalassemia carrier.Identifying pathogenic variants in these families is important as it facilitates prognosis and treatment, and allows prenatal diagnosis to be offered in future. To date the panel has assessed 10 cases of anemia with unknown cause and has made a definitive diagnosis in 8 (80%). Of the two undiagnosed, one was a child that died at 3 weeks and received multiple intrauterine and neonatal transfusions and had severe anemia and the other was a suspected case of CDA with little associated phenotype. DisclosuresNo relevant conflicts of interest to declare.

Clinical observation over the dynamic of the intrauteral mixed infection in the child of early age

Difficulty in diagnosis of the intrauterine infections (IUI) is associated with the low specificity of clinical manifestations and the multiple organ injury, prolonged persistence of the pathogen in the body, a significant prevalence of mixed infections and their frequent combination with the somatic disorders in newborns. The clinical case of mixed intrauterine infection in the child of early age is presented. The full-term boy was under the observation, he was born with severe anemic syndrome, indirect hyperbilirubinemia and hepatosplenomegaly. According to clinical observation and ultrasound of the abdomen the size of his liver and spleen increased progressively for six days after birth, it was accompanied by dynamic increase of total bilirubin due to its direct fraction, decrease of platelets count. ELISA-diagnostics of the child’s serum revealed the presence of the anti-toxoplasma and anti-cytomegalovirus antibodies. Taking into account obtained clinical and paraclinical data, the newborn child was diagnosed with intrauterine mixed infection with primary hematopoietic and liver damage (cholestatic-cytolytic variant). Anti-toxoplasma immunoglobulin was administered to child, but because of severe liver injury specific causal treatment of toxoplasmosis was postponed due to its hepatotoxicity. Later on anemic syndrome with indirect hyperbilirubinemia recurrently repeated in a child, it was dependent on transfusions but refractory to treatment. The presence of DNA of CMV and herpes virus type 6 was confirmed by PCR in the dynamic study of the five-month old child’s blood. Taking into account the obtained results of the examination, the child was diagnosed with severe congenital cytomegalovirus infection in the replication phase and comorbid congenital nonspherocytic hemolytic anemia of unknown origin with continuous crisis. The patient received anti-cytomegalovirus ganciclovir intravenously, antiherpetic valaciclovir orally. As a result of the treatment positive clinical dynamics was observed, which was accompanied by a decrease of the hepatolienal syndrome and gaining weight, but multiple red blood cell transfusions were not accompanied by significant or prolonged rise in hemoglobin levels. After the treatment twice done PCR child’s blood tests for CMV DNA were negative. Taking into account the crisis duration of the disease, splenectomy was discussed. The clinical case refers to the rare clinical diagnostic situations in medical practice when it is difficult to make a final conclusion about the etiology of the IUI. Verification of the intrauterine mixed infection was problematic in the neonatal period and during follow-up. The complexity of the diagnostic process was caused by the absence of the typical neurological symptoms. The diagnosis of mixed IUI was complicated by coexistence of the congenital nonspherocytic hemolytic anemia, the genesis of which could not be set, despite the study of enzyme activity in red blood cells, assessment of their osmotic resistance and Coombs tests. Damage of the erythroid stem hematopoiesis probably was caused by the infectious factors during the intrauteral period as well as by the hereditary pathology of the erythron.

Farklı Klinik Bulgular Gösteren Glukoz-6-Fosfat Dehidrogenaz Enzim Eksikliği Olguları: Semptomsuz Baba ve Hemolitik Anemili Kızı

Glucose-6-phosphate dehydrogenase (G6PD) is an enzyme included in the pentose phosphate pathway with a cellular protective effect against oxidative stress. The most frequent clinical manifestations of G6PD deficiency are neonatal jaundice and acute hemolytic anemia, which is usually triggered by an exogenous agent such as drugs, infections and certain nutrients. Some G6PD variants cause chronic hemolysis, leading to congenital non-spherocytic hemolytic anemia. The disorder is inherited by X-linked transmission. Homozygote females and males are the cases at risk for G6PD deficiency. A 26-month-old girl presented with hemolytic anemia after eating broad beans. She was diagnosed with G6PD deficiency and interestingly the G6DP level was also decreased in her father. There was no history of hemolytic anemia in the father despite multiple exposure to broad beans. We aimed to underline the different types of clinical expressions of G6PD deficiency in different genders by presenting this case report.