Diagnosis Of Hereditary Spherocytosis Research Articles

Clinical Exome Sequencing Reveals Novel Mutations in SPTB Gene Associated with Hereditary Spherocytosis in Patients with Suspected Congenital Hemolytic Anemia

Congenital hemolytic anemia (CHA) is defined as the premature destruction of red blood cells (RBC) due to congenital or acquired defects. The hereditary form of hemolytic anemia can be divided into hemoglobinopathies, membranopathies, and enzymopathies. Hereditary spherocytosis (HS) is the most common inherited RBC membranopathy leading to congenital hemolytic anemia. To date; five genes have been associated with HS coding for cytoskeleton and transmembrane proteins, those genes are SPTB, SLC4A1, EPB42, ANK1, and SPTA1. Due to genetic heterogeneity, clinical exome sequencing (CES) was performed on four unrelated Moroccan patients referred for CHA investigation. Sanger sequencing and qPCR were performed to confirm CES results and to study the de novo character of identified variants. The molecular analysis revealed 3 novel mutations and one previously reported pathogenic variant of the SPTB gene confirming the diagnosis of HS in the four patients. Hereditary spherocytosis anemia is a genetically heterogenous disease which could be misdiagnosed clinically. The introduction of novel sequencing technologies can facilitate accurate genetic diagnosis, allowing an adapted care of the patient and his family.

Sferocitosi: una famiglia... tre malattie

The paper describes the cases of three siblings affected by Hereditary Spherocytosis (HS). The different clinical presentations in the same family are examples of the heterogeneity of this pathology. HS is a common inherited type of haemolytic anaemia that results from abnormal morphology of erythrocytes. The clinical spectrum of HS ranges from asymptomatic forms characterized by well-compensated chronic haemolysis to severe forms with high transfusion requirement. The typical symptoms triad is anaemia, jaundice and splenomegaly while the most common complication is cholelithiasis. The diagnosis of hereditary spherocytosis in the neonate can be difficult, due to different clinical and laboratory presentations. Neonatal HS ratio, calculated by dividing the MCHC by the MCV, is a rapid and inexpensive screening. Splenectomy helps improve the patient’s quality of life and may be performed after six years of age. RHuEPO therapy should be considered in affected infants with high transfusion requirement.

Novel Biomarkers for Assessing Clinical Severity in Hereditary Spherocytosis - Application of Routine and Advanced Diagnostic Tests

Background: Hereditary spherocytosis (HS) is caused by pathogenic variants in genes encoding red blood cell (RBC) cytoskeletal and (trans)membrane proteins. This ultimately leads to instability of the RBC membrane and subsequent membrane loss, resulting in the transformation of the biconcave RBC into a poorly deformable spherocyte, which is susceptible to premature splenic clearance. The diagnosis of HS has substantially improved over the last years and new advanced techniques have been established, including osmotic gradient ektacytometry, eosin-5'-maleimide (EMA) binding test and next-generation sequencing (NGS). However, there is little knowledge on the applicability of these diagnostic outcome parameters as biomarkers for clinical severity in HS. Aim: To explore possible correlations between established and novel diagnostic outcome parameters and clinical severity in a well-defined cohort of HS patients. Methods: This monocenter retrospective cohort study involves patients diagnosed with HS upon referral to our department between 2012 and 2023. Clinical characteristics, routine and advanced diagnostic laboratory parameters, and genotype were evaluated. Clinical severity was classified as previously described, based on parameters such as hemoglobin, reticulocyte percentage and bilirubin 1. The following laboratory tests were included: routine hematological parameters (Cel-Dyn Sapphire or Alinity hq), EMA binding test, osmotic fragility test (OFT) and osmotic gradient ektacytometry (osmoscan, Lorrca MaxSis). The latter technique was also explored for other parameters than the commonly used EI max, O hyper and O min. NGS gene panel analysis was used for molecular diagnosis. Differences between groups were determined using either Chi-squared test, unpaired t-test or Mann-Whitney U test and correlations using point-biserial, Pearson's or Spearman's test via GraphPad Prism. Results: Eighty-two non-splenectomized patients were included. Thirty-five of these (42.7%) were classified as mild, and forty-seven as moderate-severe (57.3%)). Demographic characteristics nor genotype differed significantly, albeit SPTB variants occurred more frequently in the moderate-severe group (15 vs. 4 in the mild group). Expectedly, both reticulocyte count and EI max correlated with clinical severity. RBC distribution width (RDW) correlated moderately, suggesting greater RBC heterogeneity (r=0.606, p<0.0001) is associated with a more severe clinical phenotype. Similarly, EMA binding test results correlated with clinical severity (r=0.390, p<0.001), indicating more pronounced membrane loss in clinically more severe patients. We further evaluated three novel osmoscan parameters ( Figure 1): EI O290, the elongation index (EI) at physiologic isotonicity, which correlated with clinical severity (r=-0.500, p<0.0001), and also with EI max (r=0.856, p<0.0001). The O min-width and O max-width, defined as the difference in osmolality between the intersection points of y=EI min or EI max +/- 0.05 and the osmoscan curve. Thisassesses the effect of changes in osmolality on EI min or EI max, respectively. O min-width correlated with RDW (r-0.439, p<0.0001), OFT results (N=30, r=0.671, p<0.0001) and clinical severity (r=0.390, p<0.001). O max-width correlated with clinical severity (r=-0.375, p<0.001) and strongly with percentage of hyperchromic cells (N=76, r=-0.751, p<0.0001), yet weakly with RDW (-0.273, p<0.05). All significant correlations with clinical severity are displayed in Figure 2. Conclusion: In this study, a number of routine and advanceddiagnostic laboratory parameters were found to correlate with clinical severity in HS. O min-width and O max-width are novel osmoscan-derived biomarkers that correlated with RDW, hyperchromic cells (O max-width), OFT results (O min-width) and clinical severity. EI O290, another novel osmoscan-derived biomarker, also correlated with clinical severity, although not stronger than EI max and AUC. The biomarkers identified in this study, together with patient-reported outcome measures (PROMs), could be used to revise the previously established severity classification system and thereby aid in stratifying clinical severity and subsequent clinical decision-making.

A Rare Case of "Periportal Cuffing" as an Incidental Finding on 18F-FDG PET/CT.

A 7-year-old boy with known diagnosis of hereditary spherocytosis and ulcerative colitis was referred for 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography after detection of a 28 mm lesion suspicious for malignancy in spleen on upper abdomen magnetic resonance imaging (MRI). As an incidental finding, a moderately increased uptake of 18F-FDG was observed in periportal region with no definable mass. MRI revealed compatible findings with "periportal cuffing" as described on ultrasonography.

A stepwise diagnostic approach for undiagnosed Anemia in children: A model for low-middle income country

BackgroundReaching a precise diagnosis in rare inherited anemia is extremely difficult and challenging, especially in areas with limited use of genetic studies, which makes undiagnosed anemia a unique clinical entity in tertiary hematology centers. In this study, we aim at plotting a stepwise diagnostic approach in children with undiagnosed anemia while identifying indications for genetic testing. Patients and methodsA one-year cross-sectional study involved 44 children and adolescents with undiagnosed anemia after undergoing an initial routine panel of investigations. They were classified based on mean corpuscular volume (MCV) into 3 groups: microcytic (n = 19), normocytic (n = 14) and macrocytic (n = 11). An algorithm that included four levels of investigations was devised for each category. ResultsAfter applying a systematic diagnostic approach, 33 patients (75 %) were diagnosed of whom 7 (15 %) had combined diagnoses, while 11 (25 %) patients remained undiagnosed. Based on the first, second, third and fourth levels of investigations, patients were diagnosed, respectively, as follows: of the 11 patients, 7 were microcytic, 3 normocytic and 1 macrocytic; of the 7 patients, 2 were microcytic, 2 normocytic, and 3 macrocytic; of 10 patients, 5 were microcytic, 4 normocytic and 1 macrocytic; finally, of the 16 patients, 8 were microcytic, 6 normocytic and 2 macrocytic. Numbers recorded appear higher than the actual number of the patients because some of them were diagnosed by more than one level of investigation. The diagnoses obtained in the microcytic group showed hemoglobinopathies, iron refractory iron deficiency anemia (IRIDA), membrane defects, sideroblastic anemia, hypo-transferrinemia, a combined diagnosis of sickle cell trait and pyropoikilocytosis. The diagnoses also showed a combined diagnosis of hereditary spherocytosis (HS) and alpha thalassemia minor, and a combined diagnosis of iron deficiency anemia and beta thalassemia minor, while 15 % remained undiagnosed. In the normocytic group, the diagnosis revealed autosomal recessive (AR) HS, vitamin B12 deficiency, pyruvate kinase deficiency (PKD), congenital dyserythropoietic anemia (CDA) type I, Diamond Blackfan anemia and beta thalassemia major. In addition, it showed a combined diagnosis of AR HS and CDA type II, a combined diagnosis of AR HS and PKD, and a combined diagnosis of dehydrated stomatocytosis (DHS) and G6PD carrier, meanwhile 20 % remained undiagnosed. Finally, the macrocytic group was diagnosed by vitamin B12 deficiency, sideroblastic anemia, PKD, a combined diagnosis of PKD and G6PD deficiency carrier, while 45 % remained undiagnosed. ConclusionConducting a stepwise approach with different levels of investigations may help reach the diagnosis of difficult anemia without having to resort to unnecessary investigations. Combined diagnosis is an important cause of undiagnosed anemia, especially in countries with high frequency of consanguinity. The remaining 25 % of the patients continued to be undiagnosed, requiring more sophisticated investigations.

A de novo ANK1 mutation in a childhood hereditary spherocytosis: a case report

BackgroundDue to the heterogeneity of the phenotype of Hereditary spherocytosis (HS) patients, some patients may have rare clinical complications such as biliary obstruction and ultra-high bilirubinemia.Case presentationA 8-y-old boy presented to the emergency with complaints of anemia for 6 years and worsened abdominal pain and scleral yellowing of the skin for 2 days. Physical examination showed tenderness in the middle and upper abdomen and splenomegaly. Abdominal CT revealed biliary obstruction. Genetic analysis revealed a de novo mutation in the gene ANK1, HS with biliary obstruction was diagnosed. The surgery of bile duct exploration and T-tube drainage, and splenectomy were performed successively. This patient was followed up for 13 months after splenectomy, and his condition was stable.ConclusionThe diagnosis of HS is not clinically difficult, and once a patient with HS is diagnosed, regular follow-up management and standardized treatment are required. Genetic testing is also needed to screen for other genetic disorders that may co-exist in patients with HS who do not have a good efficacy or who have a long-term chronic onset of jaundice.

Clinical and genetic diagnosis for 26 paitents with hereditary spherocytosis.

Hereditary spherocytosis (HS) is the most common hereditary defect of the red cell membrane, mainly characterized by anemia, jaundice, and splenomegaly. Due to the atypical clinical manifestations and negative family history of some patients, as well as the low sensitivity and specificity of traditional laboratory examinations, it is easy for it to escape diagnosis or be misdiagnosed. At present, it has been confirmed that the mutation of ANK1, SPTB, SPTA1, SLC4A1 and EPB42 genes can cause the deletion of their corresponding coding proteins, and thus lead to the defect of erythrocyte membrane. This study aims to analyze the feasibility and clinical application value of HS gene diagnosis. Data of 26 patients from Hunan, China with HS admitted to the Department of Hematology, Second Xiangya Hospital of Central South University from January 2018 to September 2021 were retrospectively collected, and their clinical manifestations and results of laboratory examinations were analyzed. Next-generation sequencing (NGS) combined with Sanger sequencing were applied. The mutation of HS pathogenic gene and the variation of uridine diphosphate-glucuronosyl transferase 1 family polypeptide A1 (UGT1A1), a key enzyme in the regulation of bilirubin metabolism, were detected. The results of pathogenic gene variations were interpreted pathogenic gene variations in accordance with the Standards and guidelines for the interpretation of sequence variants published by the American College of Medical Genetics and Genomics (ACMG). The clinical characteristics of patients with different gene variants were analyzed, and the clinical diagnosis and genetic diagnosis were compared. Among the 26 patients with HS, there were 23 cases of anemia, 25 cases of jaundice, 24 cases of splenomegaly, and 14 cases of cholelithiasis. There were 16 cases with family history and 10 cases without family history. The results of HS mutation test were positive in 25 cases and negative in 1 case. A total of 18 heterozygous mutations of HS pathogenic genes were detected in 19 families, among which 14 were pathogenic, 1 was likely pathogenic and 3 were of unknown significance. SPTB mutations (12) and ANK1 mutations (4) were the most common. The main variation types were nonsense mutation (9). There were no significant differences in peripheral blood cell parameters and hemolysis indicators between the SPTB mutant group and the ANK1 mutant group (all P>0.05). The rate of splenectomy in ANK1 mutation group was higher than that in SPTB mutation group, and the difference was statistically significant (χ2=6.970, P=0.014). There were no significant differences in peripheral blood cell parameters and hemolysis indicators among different mutation types (nonsense mutation, frameshift mutation, splice site mutation and missense mutation) (all P>0.05). Among the 18 clinically confirmedpatients, there were 17 cases whose diagnosis is consistent with the genetic diagnosis. Eight patients were clinically suspected, and all of them were confirmed by detection of HS gene mutation. Twenty-four patients with HS underwent UGT1A1 mutation detection, among which 5 patients carried UGT1A1 mutation resulting in a decrease in enzyme activity, and 19 patients had normal enzyme activity. The level of total bilirubin (TBIL) in the group with reduced enzyme activity was higher than that in the group with normal enzyme activity, and the difference was statistically significant (U=22, P=0.038). Most patients with HS have anemia, jaundice and splenomegaly, often accompanied by cholelithiasis. SPTB and ANK1 mutations are the most common mutations in HS pathogenic genes among patients in Hunan, China, and there was no significant correlation between genotype and clinical phenotype. Genetic diagnosis is highly consistent with clinical diagnosis. The decrease of UGT1A1 enzyme activity can lead to the aggravation of jaundice in HS patients. Clinical combined gene diagnosis is beneficial for the rapid and precision diagnosis of HS. The detection of UGT1A1 enzyme activity related gene variation plays an important role in evaluation of HS jaundice.

Membrane Protein Detection and Morphological Analysis of Red Blood Cells in Hereditary Spherocytosis by Confocal Laser Scanning Microscopy.

In hereditary spherocytosis (HS), genetic mutations in the cell membrane and cytoskeleton proteins cause structural defects in red blood cells (RBCs). As a result, cells are rigid and misshapen, usually with a characteristic spherical form (spherocytes), too stiff to circulate through microcirculation regions, so they are prone to undergo hemolysis and phagocytosis by splenic macrophages. Mild to severe anemia arises in HS, and other derived symptoms like splenomegaly, jaundice, and cholelithiasis. Although abnormally shaped RBCs can be identified under conventional light microscopy, HS diagnosis relies on several clinical factors and sometimes on the results of complex molecular testing. It is specially challenging when other causes of anemia coexist or after recent blood transfusions. We propose two different approaches to characterize RBCs in HS: (i) an immunofluorescence assay targeting protein band 3, which is affected in most HS cases and (ii) a three-dimensional morphology assay, with living cells, staining the membrane with fluorescent dyes. Confocal laser scanning microscopy (CLSM) was used to carry out both assays, and in order to complement the latter, a software was developed for the automated detection of spherocytes in blood samples. CLSM allowed the precise and unambiguous assessment of cell shape and protein expression.

Targeted next-generation sequencing identifies novel deleterious variants in ANK1 gene causing severe hereditary spherocytosis in Indian patients: expanding the molecular and clinical spectrum.

Hereditary Spherocytosis (HS) is a common cause of hemolytic anemia varying from mild to severe hemolysis due to defects in red cell membrane protein genes, namely ANK1, SPTB, SPTA1, SLC4A1, and EPB42. These genes are considerably very large spaning 40-50 exons making gene-by-gene analysis costly and laborious by conventional methods. In this study, we explored 26 HS patients harboring 21 ANK1 variants identified by next-generation sequencing (NGS), characteristics and spectrum of the detected ANK1variants were analyzed in this study. Clinically, all the HS patients showed moderate to severe transfusion-dependent hemolytic anemia, some requiring splenectomy. We identified 13 novel and 8 reported variants, mainly 9 frameshifts, 2 missense, 6 nonsense, and 4 splice site ANK1 variants, using NGS technology. Frameshifts were remarkably the most common variant type seen in Indian HS patients with ANK1 gene defects. We have also explored expression levels of red cell membrane ankyrin protein by flow cytometry in 14 HS patients with ANK1 gene defects and a significant reduction in ankyrin protein expression has been found. This report mainly illustrates the molecular and phenotypic heterogeneity of ANK1 variants causing HS in Indian patients. Ankyrin-1 mutations are a significant cause of loss of function in dominant HS in the Indian population. Comprehensive genetic and phenotypic evaluation assists in implementing the knowledge of genetic patterns and spectrum of ANK1 gene variants, providing molecular support for HS diagnosis.

Use of Red Cell Indices for Screening of Hereditary Spherocytosis in Neonates: A Report of Two Cases Confirmed by Exome Sequencing

Prolonged unconjugated hyperbilirubinaemia is defined as neonatal jaundice persisting beyond 14 days of life. Hereditary Spherocytosis (HS) often remains underdiagnosed and is a notable cause of prolonged neonatal jaundice. Coombs negative haemolytic anaemias are an important cause of unconjugated hyperbilirubinaemia, and HS is one of the most common inherited red cell membrane disorders. Other causes of prolonged unconjugated jaundice include extravasated blood (cephalhaematoma, bruises, intraventricular haemorrhage in preterm infants), haemolysis (blood group incompatibility, red blood cell enzymopathies, and membranopathies), urinary tract infection, congenital hypothyroidism, and rare familial disorders such as Gilbert’s syndrome and Crigler-Najjar syndromes I and II. Herein, the authors present a case report of two male neonates (three week-old and 25dayold) who presented with hyperbilirubinaemia requiring intensive phototherapy, blood transfusion, an exchange transfusion, and were diagnosed with HS. A significant family history suggested haemolytic anaemia, and red cell indices, namely Mean Corpuscular Haemoglobin Concentration (MCHC), Mean Corpuscular Volume (MCV), and the ratio of MCHC/MCV (neonatal HS index), helped suspect HS. Whole exome sequencing identified the specific mutation and confirmed the diagnosis of HS. Both of these neonates presented with prolonged neonatal jaundice, and HS was suspected based on the family history and red cell indices, namely MCHC and MCHC/MCV ratio, as highlighted in the present case series.

Utility of Cryohemolysis Test in the Diagnosis of Hereditary Spherocytosis.

Diagnosis of Hereditary spherocytosis (HS) often requires time-consuming and/or expensive tests. Cryohemolysis test (CHT) is a simple and easy to perform test with high predictive value for HS diagnosis. In this prospective study, we evaluated the diagnostic utility of CHT for the diagnosis of HS. We included 60 suspected HS patients, 18 patients with Autoimmune hemolytic anemia (AIHA) and 120 healthy controls. Among the 60 suspected cases, there were 36 HS cases and 24 with other hemolytic anemias. The mean CHT (%) ± SD for controls, AIHA, other hemolytic anemias, and HS was 6.63 ± 2.79, 6.79 ± 4.36, 6.61 ± 2.76 and 26.7 ± 8.9, respectively. The CHT % was significantly higher in HS group when compared to controls (p = < 0.0001), AIHA (p = < 0.0001) and other hemolytic anemia groups (p = < 0.0001). At a CHT cut off of > 18.3%, the sensitivity, specificity, positive predictive value and negative predictive value for diagnosis of HS in our study were 97.1%, 94.4%, 97.2% and 90.3%, respectively. CHT is a simple and sensitive test for the diagnosis of HS but remains underutilized. The addition of CHT in the diagnostic workup of HS will be very useful, especially in a resource limited setting.

A novel splicing mutation of ANK1 is associated with phenotypic heterogeneity of hereditary spherocytosis in a Chinese family

Hereditary spherocytosis (HS) is a common hematological genetic disorder that results in anemia, jaundice and splenomegaly. It is caused by mutations in the ANK1, SPTA, SPTB, SLC4A1 and EPB42 genes, which encode red blood cell membrane and skeletal proteins. Patients show high heterogeneity in phenotype and genotype and the genotype-phenotype correlation still requires clarification. Here, a novel splicing mutation (ANK1: c.4391-2 A>C) was identified by whole-exome sequencing (WES) and Sanger sequencing in a Chinese boy who exhibited a moderately severe HS phenotype. However, his father exhibited a mild phenotype, despite carrying the same HS-causing mutation. The function of the mutant ANK1 protein was analyzed by both bioinformatics and experimental analysis. The mutant protein (p.N1463Kfs*4) showed a different 3D-structure and altered subcellular localization, when compared with the wild-type ANK1 protein. These changes disrupted the normal cell membrane structure and resulted in spheroidized red blood cells. Amplification of cDNA from the son and his father revealed a difference in expression of the abnormal transcript produced by the splicing mutation. We proposed that the lower expression of the mutant allele may have contributed to the relatively mild symptoms of the father. Our study verified ANK1 c. c.4391-2 A>C as a novel pathogenic mutation that causes HS. We have also provided new insights into the interpretation of phenotypic variability within families, which could greatly improve the clinical diagnosis and genetic counseling of HS.

Hereditary spherocytosis complicated by intrahepatic cholestasis: two case reports

Hereditary spherocytosis (HS) is not a rare disease in the department of hematology; however, in the late stage of the disease, patients often have very severe cholestasis and are referred to the department of hepatology. Hepatologists may have trouble determining the source of cholestasis, causing treatment difficulties. We report two 20-year-old patients complaining of "skin and eyes turned to yellow". Patient 1 had no previous hematologic disorders, and patient 2 had a history of anemia without treatment. Laboratory tests suggested anemia and elevated bilirubin in both patients. The direct bilirubin levels were more significantly elevated than the indirect bilirubin levels in both patients, and the patients both suffered from abdominal pain and pancreatitis. However, the degree of anemia could not fully explain the jaundice. Magnetic resonance imaging findings suggested the presence of hepatosplenomegaly and gallstones. Genetic testing identified new mutations in the relevant genes, ultimately confirming the diagnosis of HS. The liver biopsy results for both patients showed obvious intrahepatic cholestasis. Patient 1 underwent splenectomy at a bilirubin level of 125.4 µmol/L, and the bilirubin level returned to normal after surgery, with a good prognosis. However, Patient 2 suffered from pancreatitis during hospitalization and was unable to undergo splenectomy. Endoscopic retrograde cholangiopancreatography was implemented, but the bilirubin level continued to rise, and Patient 2 ultimately gave up treatment and passed away. For hepatologists, identifying the source of jaundice (hemolysis, hepatocyte destruction, or biliary obstruction) is important for treatment, supplemented by liver biopsy and genetic testing if necessary. In the 2 cases covered in this article, early-stage HS caused hemolytic jaundice with predominantly elevated indirect bilirubin, and as the disease progressed, patients developed severe cholestasis probably related to transient biliary obstruction caused by gallstones and hepatocellular injury due to abnormal bilirubin metabolism. In addition, in patients with HS combined by intrahepatic cholestasis, early consideration of splenectomy may delay disease progression and achieve a better prognosis. Of course, this conclusion needs to be confirmed by more clinical studies.

Literature review on genotype-phenotype correlation in patients with hereditary spherocytosis.

Hereditary spherocytosis (HS) is a prevalent inherited hemolytic disorder primarily reported in Caucasians. Recently, next-generation sequencing (NGS) techniques have shown tremendous potential in the diagnosis of HS. HS commonly originates from variants in ANK1, SPTB, SLC4A1, SPTA1, and EPB42. This review is focused on 13 previous clinical studies on genotype-phenotype correlation, which might promote the role of causative variants in the diagnosis and prognosis of HS. Most studies have focused on the pediatric population and Asian countries. The occurrence of novel variants was common in each cohort, and variants with a high frequency of causative genes were demonstrated. In conclusion, patients with variants in SPTA1 and SLC4A1 were reported to have more severe and milder anemia, respectively. ANK1 and SPTB are the most common variants in patients with HS, and no significant difference in phenotypes was observed between patients with variants in ANK1 versus SPTB. The types and locations of variants might influence the phenotype of each genotype, whereas the roles of concomitant pathogenic genes and the source of variants deserve further investigation.

A case report of hereditary spherocytosis (HS): Approach to diagnosis and management of HS

Hereditary spherocytosis (HS) is a type of congenital hemolytic anemia, in which heterogeneous alterations in one of the six genes that encode for proteins involved in vertical associations which tie the red blood cell (RBC) membrane skeleton to the lipid bilayer causesdysfunction or deficiency of cell membrane protein resulting in spherical-shaped, hyper- dense, and poorly deformable RBCs with a shortened life span. We report a case of HS in a 2-month-old female who presented with severe anemia, jaundice, and hepatosplenomegaly.The peripheral blood smear showed spherocytosis and reticulocytosis. The osmotic fragility was positive and direct antiglobin test was negative. The osmotic fragility test and direct antiglobulin test were positive. She was managed with packed RBCs (PRBCs) transfusionand folic acid supplementation.

P1531: HETEROGENEITY OF DISEASE-CAUSING GENOTYPES BETWEEN FAMILIES WITH HEREDITARY SPHEROCYTOSIS: A SINGLE-CENTER COHORT STUDY

Background: Hereditary spherocytosis (HS) is a phenotypically and genetically heterogeneous disease, in which erythrocytes are unable to maintain their normal biconcave shape due to genetic mutations in membrane/cytoskeletal proteins that play a role in structural morphologic stability. Recent progress in genomic analyses technologies has helped to shed light on the complexity of genotype/phenotype correlations within this orphan hemolytic red blood cell disorder. Aims: In this retrospective investigation, we aim to investigate the genotype-phenotype correlation based on the clinical severity of the disease and the gene-wise predicted pathogenicity comparison. Furthermore, we want to highlight the importance of next generation sequencing (NGS) technologies in the diagnosis of HS. Methods: We provide the results of a single-center study in Austria on a total of 69 patients (core group, N=35; affected family members, N=34) with HS, focusing on NGS results (both exome and panel sequencing), ancestry, laboratory findings, clinics, as well as genotype-phenotype correlations. Results: A pathogenic (N=59/69; core group, N=29/35) or likely pathogenic variant (N=6/69; core group N=3/35) was identified in 94% (core group 91%) of the patients, including 18 novel variants. Variants in ANK1 (46%; European ancestry 37%, non-European 9%) were most encountered, followed by SPTB (31%, all European) and SLC4A1 (14%; European 11%, non-European 3%). In three patients (9%, all European) we were unable to identify the genetic cause unequivocally. Except for a heterozygous intronic ANK1 c.1504-9G>A variant, which was identified in two unrelated European families, there was no overlap on causative variants. The majority of mutations (N=25; 81%) were of high impact and include frameshifts, N=14 (45%); nonsense, N=8 (26%); CNVs, N=2 (6%) and splice-site variants, N=1 (3%). Sufficient data for phenotype-genotype correlation testing were available for 56 patients (core group, N=35), and phenotypes were milder in the patients with SLC4A1 variants. Patients with ANK1 and SPTB variants had comparable phenotypes. Summary/Conclusion: To our knowledge, this is the first study describing genomics (N=69) and genotype-phenotype correlation (N=56) in patients with HS in Central-Europe. We were able to identify causative variants in 94% of the 69 patients, including atypical disease-causing genetic findings such as intronic and CNV mutations. This evidenced the compelling need of a combination of standardized NGS analysis and clinical deep investigation in order to accurately characterize and treat HS patients.

Influence of diabetes and hypercholesterolemia on laboratory methods for hereditary spherocytosis diagnosis.

IntroductionHereditary spherocytosis (HS) is characterized by decreased erythrocyte deformability resulting in hemolytic anemia. This is a heterogeneous disease regarding underlying protein deficiency, disease severity, age at diagnosis and clinical course. Although largely considered as pediatric disease, HS could be initially diagnosed also in elder patients as a result of gallstones or splenomegaly fortuitous finding. Concurrently, common adulthood metabolic disorders like diabetes or dyslipidemia are also known to impair RBC rheology and deformability. Therefore, we aimed to investigate if these diseases affect the screening and diagnostic tools used for HS diagnosis.MethodsWe applied our workflow for HS diagnosis on 95 pathological samples: 29 patients with diabetes, 20 with hypercholesterolemia, 17 with dyslipidemia, 6 with hypertriglyceridemia, 23 with metabolic syndrome (MS). Thus, a total of 73 samples were analyzed by automated reticulocyte analysis, 52 by cryohemolysis test, and 41 by ektacytometry osmoscan analysis as we used two out of the three tests for each individual sample.ResultsApplying our screening algorithm based on automated reticulocyte indices, a total of 4 samples (4.2%): one sample (5%) from the diabetes group and three samples (16.7%) from the MS group, positioned into the HS zone. However, no significant difference was found between any of the pathological groups and the controls for the cryohemolysis test or the osmoscan.ConclusionWhile diabetes and hypercholesterolemia are pathologic conditions known to present with decreased erythrocyte deformability and disturbed rheology, their possible concomitant presence with HS would not interfere with the screening and confirmatory laboratory methods.

The diagnostic protocol for hereditary spherocytosis-2021 update.

BackgroundHereditary spherocytosis (HS), a commonly encountered hereditary hemolytic disease, is mostly inherited in an autosomal dominant manner. The clinical manifestations in patients with HS show obvious heterogeneity. Moreover, the sensitivity or specificity of some HS diagnostic tests are not ideal and may easily result in misdiagnosis or missed diagnosis in some patients. The objective of this study was to propose a simple and practical diagnostic protocol, which can contribute to the diagnosis of HS and its differential diagnosis with different types of hemolytic anemia such as thalassemia (THAL), autoimmune hemolytic anemia (AIHA), and glucose‐6‐phosphate dehydrogenase (G6PD) deficiency, thus, to provide an alternative simple and reliable method for better clinical diagnosis of HS.MethodsThrough combing our research with existing experimental technologies and studies, we propose a simple and practical protocol for HS diagnosis, which will help clinicians to improve HS diagnosis.ResultsCompared with the existing HS diagnostic protocols, the HS diagnostic protocol we proposed is simpler. In this new protocol, some experimental tests with ideal diagnostic efficiency are added, such as mean reticulocyte volume (MRV), mean sphered cell volume (MSCV), mean corpuscular volume (MCV), in combination with the observation of clinical manifestations, family investigation, routine tests for hemolytic anemia, genetic testing, and other screening tests.ConclusionThe HS diagnostic protocol we proposed could improve the clinical practice and efficiency of HS diagnosis.

Comparison of a modified flow cytometry osmotic fragility test with the classical method for the diagnosis of hereditary spherocytosis.

Hereditary spherocytosis (HS) is the most common inherited hemolytic anemia. The flow cytometric test using eosin-5'maleimide (EMA) is a well-established diagnostic method. However, in order to improve HS detection, it is recommended that EMA and an osmotic fragility test (OFT) both be performed. OFT is time consuming and labor intensive. We used a flow cytometric (FOFT) adaptation of the classical OFT reported by Yamamoto. We compare the FOFT to the classical OFT including practical data and propose options for simplifying this method. Suspected and known HS patients and controls were tested by the following methods: EMA, OFT, and FOFT including some modifications. The FOFT method is robust and correlates to loss of red blood cells. OFT and FOFT gave similar results in healthy controls and four HS patients. Normal range for FOFT in 70 adults is shown and can be used as a reference value. Neonates should have their own normal range defined. Overnight sample incubation at 37°C did not add information to the FOFT results. Our modified Yamomoto FOFT can replace the classic OFT as the addition to EMA for the diagnosis of HS. The use of flow cytometry in both these methods requires small sample volume, is reproducible, simpler, and produces results more rapidly.

Difficulty in Diagnosis of Hereditary Spherocytosis in the Neonate.

Difficulty in Diagnosis of Hereditary Spherocytosis in the Neonate.