Identification of novel variants in hereditary spherocytosis patients by whole-exome sequencing.

Defects in erythrocyte membrane proteins can cause the most common type of inherited hemolytic anemia, so called hereditary spherocytosis (HS). It is characterized by the appearance of spherocytes in peripheral blood, hemolytic anemia, splenomegaly, jaundice and gallstones. Due to difficulty of diagnosis solely based on aforementioned parameters, the addition of genetic testing seems to be effective and most acknowledged. Up to date, pathogenic variations in five genes encoding membrane proteins (ANK1, SPTA1, SPTB, SLC4A1, EPB42) are identified to cause HS. Here, we have studied the genetic spectrum in forty-one patients with clinically suspected HS and their families, as well as their genotype-phenotype correlations. Pathogenic mutations in ANK1, SPTB, SLC4A1 and SPTA1 were found in 17 (41.5 %), 12 (29.3 %), 7 (17.1 %) and 5 (12.2 %) patients, respectively. Deleterious variants include 12 missense, 15 nonsense, 12 frameshift, and 4 splicing variants. Among these variations 32 were novel. In our genotype-phenotype analysis, platelet levels in SPTB (p = 0.021) and SLC4A1 (p = 0.02) patients were found to be significantly lower than ANK1 patients. In addition, LDH levels in SPTB patients were remarkably lower than patients with ANK1 mutations (p = 0.025).

A Case of Adult Hereditary Spherocytosis Concomitant with Gilbert Syndrome Caused by Mutations in SPTB and UGT1A1.

Hereditary spherocytosis (HS) is the most common hereditary hemolytic disease with defects in red blood cells (RBC) membrane proteins caused by mutations in membrane protein genes, like SPTB, SPTA1 and ANK1. Gilbert syndrome (GS) is a disease characterized by a mild deficiency of uridine diphosphate-glucuronosyltransferase 1A1 (UGT1A1) enzyme activity and unconjugated hyperbilirubinemia, largely caused by UGT1A1 mutations. The two inherited diseases HS and GS are rarely occurred in the same patient and are easy to be misdiagnosed, resulting in excessive diagnosis and treatment. Here, we report a rare case of HS combined with GS due to mutations in the SPTB and UGT1A1 genes. A 50-year-old man who had an over 40-year history of jaundice was admitted to our hospital owing to fatigue and fever. His blood analysis showed low hemoglobin (74 g/L), high reticulocyte (23.5%) and high serum bilirubin (65 µmol/L); abdominal ultrasound revealed calculous cholecystitis and splenomegaly. Considering a possible diagnosis of hemolytic anemia, further examinations showed 42% spherocytes in blood smears and high erythroid lineage hyperplasia in bone marrow. Subsequently, 151 jaundice-related genes panel sequencing was done and results showed SPTB p.N1260fs and UGT1A1 p.G71R mutations. Then the patient was diagnosed with HS complicated with GS. Anti-infection and supportive treatments were providing to the patient, while infection removed, the hemoglobin recovered to normal, and no additional treatment was given. These findings of this report indicate that patients who are considered hemolytic anemia presenting with jaundice and anemia, genetic testing is a crucial method for the final diagnosis and bilirubin metabolic disease should also be concerned.

A Rare Case of Iron Overload in Hereditary Spherocytosis: A Case Report.

Hereditary spherocytosis (HS) is a hereditary hematologic disorder characterized by fragile spherical red blood cells that are susceptible to hemolysis. HS patients are often asymptomatic or present with anemia; however, serious complications of chronic hemolysis can include cholelithiasis and aplastic crisis. Splenectomy is considered the standard surgical treatment in moderate and severe forms of HS, with the main complication being a life-long risk of infection. Interestingly, our case suggests a possibility of secondary hemochromatosis as a complication of chronic hemolysis seen in HS. A vast majority of hemochromatosis patients possess a genetic predisposition, which increases their serum iron level and iron storage within the reticuloendothelial system. However, we present a case in which the genetic panel for common mutations associated with hemochromatosis resulted as negative. This case emphasizes the need for increased awareness regarding the potential development of idiopathic hemochromatosis in patients with long-standing HS, allowing for prompt intervention and preventing the associated complications.

A novel variant in the SPTB gene underlying hereditary spherocytosis and a literature review of previous variants.

BACKGROUND: Hereditary spherocytosis (HS, MIM#612641) is one of the most common hereditary hemolytic disorders. This study aimed to confirm a novel variant's pathogenicity and reveal a patient's genetic etiology. METHODS: The clinical data of a patient with HS who underwent genetic sequencing at the Children's Hospital of Chongqing Medical University were reviewed retrospectively. In silico prediction and in vitro minigene splicing reporter system were then conducted on the detected variant to analyze its intramolecular impact. A summary of the literature related to HS due to SPTB gene variants was also presented. RESULTS: A novel variant (c.301-2 A > G) in the SPTB gene (NM_001024858.4) was identified in the proband. Using Sanger sequencing, we conclusively confirmed that the inheritance of the variant could not be traced to the biological parents. The in vitro minigene assay revealed three different transcripts derived from the c.301-2 A > G variant: r.301_474del, r.301_306delCCAAAG, and r.301-1_301-57ins. Through a literature review, patients with HS who had been genotypically validated were summarized and the SPTB gene variant profile was mapped. CONCLUSION: We identified a splicing variant of the SPTB gene, thus confirming its aberrant translation. The novel variant was the probable genetic etiology of the proband with HS. Our findings expanded the variant spectrum of the SPTB gene, thus improving the understanding of the associated hereditary hemolytic disorders from a clinical and molecular perspective and contributing to the foundation of genetic counseling and diagnosis.

Clinical and genetic characteristics of Chinese pediatric and adult patients with hereditary spherocytosis.

OBJECTIVE: This study aimed to investigate the clinical features, pathogenic gene variants, and potential genotype-phenotype correlations in Chinese patients with hereditary spherocytosis (HS). METHODS: Retrospective analysis of clinical data and molecular genetic characteristics was conducted on patients diagnosed with HS at Jiangxi Provincial Children's Hospital, the Second Affiliated Hospital of Nanchang University, Pingxiang People's Hospital and The Third People's Hospital of Jingdezhen between November 2017 and June 2023. Statistical analyses were performed to compare and analyze the red blood cell (RBC), hemoglobin (HB), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC) data between and within groups based on different mutations and age groups (< 14 and ≥ 14 years). RESULTS: A total of 34 HS patients were included in this study, comprising 22 children (64.70%) and 12 adults (35.30%). The probands who underwent genetic testing were derived from 34 unrelated families. Thirty-two variants were tested and 9 of them are novel. Eighteen cases had ANK1 variants, 15 had SPTB variants, and 1 had SLC4A1 variant. 25 patients performed core family members underwent genetic testing, 17 (68.0%, 17/25) were de novo, 5 (20.0%, 5/25) were maternally inherited, and 3 (12.0%, 3/25) were paternally inherited. ANK1-HS patients exhibited more severe anemia compared to cases with SPTB-HS, showing lower levels of RBC and HB (P < 0.05). Anemia was more severe in patients diagnosed in childhood than in those diagnosed in adulthood. Within the ANK1-HS group, MCH levels in adult patients was significantly higher than those in children (P < 0.05), while there were no significant differences in RBC, HB, MCV, and MCHC levels between two groups. Adult patients with SPTB-HS had significantly higher levels of RBC, HB, and MCH than pediatric patients (P < 0.05), while MCV and MCHC levels showed no significant statistical differences. CONCLUSION: This study conducted a comparative analysis of phenotypic characteristics and molecular genetics in adult and pediatric patients diagnosed with HS, confirming that pediatric ANK1-HS patients exhibit a more severe anemic phenotype compared to SPTB-HS patients, while the severity of HS in adults does not significantly differ between different causative genes.

Complex heterozygous mutations in hereditary spherocytosis: A case report.

BACKGROUND: The aim of this study was to investigate the complex heterozygous mutations of ANK1 and SPTA1 in the same individual and improve our understanding of hereditary spherocytosis (HS) in children. We also hope to promote the application of gene detection technology in children with HS, with the goals of identifying more related gene mutations, supporting the acquisition of improved molecular genetic information to further reveal the pathogenesis of HS in children, and providing important guidance for the diagnosis, treatment, and prevention of HS in children. CASE SUMMARY: A 1-year and 5-month-old patient presented jaundice during the neonatal period, mild anemia 8 months later, splenic enlargement at 1 year and 5 months, and brittle red blood cell permeability. Genetic testing was performed on the patient, their parents, and sister. Swiss Model software was used to predict the protein structure of complex heterozygous mutations in ANK1 and SPTA1. Genetic testing revealed that the patient harbored a new mutation in the ANK1 gene from the father and a mutation in the SPTA1 gene from the mother. Combined with the clinical symptoms of the children, it is suggested that the newly discovered complex heterozygous mutations of ANK1 and SPTA1 may be the cause, providing important guidance for revealing the pathogenesis, diagnosis, treatment, and promotion of gene detection technology in children with HS. CONCLUSION: This case involves an unreported complex heterozygous mutation of ANK1 and SPTA1, which provides a reference for exploring HS.

Flow Cytometry as a New Accessible Method to Evaluate Diagnostic Osmotic Changes in Patients with Red Blood Cell Membrane Defects.

Hereditary spherocytosis (HS) is a membranopathy that impacts the vertical junctions between the cytoskeleton and the plasma membrane of erythrocytes. The gold standard method for diagnosing it is osmotic gradient ektacytometry (OGE). However, access to this technique is scarce. We have devised a straightforward approach utilizing flow cytometry to quantify variations in an osmotic gradient, relying on FSC-H/SSC-H patterns. We studied 14 patients (9 pediatric, 5 adults) and 54 healthy controls (16 pediatric, 38 adults). After assessing the behavior of the samples in several osmolar gradients we selected for the study the 176, 308, and 458 mOsm/kg levels as hypo-osmolar, iso-osmolar, and hyper-osmolar references. We then selected the iso-osmolar point for assessment to determine its efficacy in discriminating between patient and control groups using a receiver operating characteristic curve. In the pediatric group, the area under the curve (AUC) was 1.0, indicating 100% sensitivity and 93.3% specificity. Conversely, in the adult group, the AUC was 0.98, with 80% sensitivity and 90.9% specificity. We introduce a method that is easily replicable and demonstrates high sensitivity and specificity. This technique could prove valuable in the diagnosis of spherocytosis.

Coexistence of hereditary spherocytosis with SPTB P.Trp1150 gene variant and Gilbert syndrome: A case report and literature review.

A congenital protein anomaly in the erythrocyte membrane skeleton causes a hereditary haemolytic illness known as hereditary spherocytosis (HS). The primary characteristic of HS is an increase in the number of tiny spherical red blood cells in the peripheral blood. The chief clinical features of HS include anaemia, jaundice, splenomegaly, spherical erythrocytosis in the blood, chronic anaemia with haemolysis, and recurrent acute attacks. Most patients have a family history; some have autosomal recessive inheritance, whereas most have autosomal dominant inheritance. In cases of severe hyperbilirubinemia disproportionate to haemolysis, other causes of hyperbilirubinemia should be considered. Gilbert syndrome (GS) is an autosomal dominant illness caused by the reduced activity of uridine diphosphate-glucuronosyl transferase lAl and is characterised by intermittent hyperbilirubinemia without any other signs or symptoms of liver disease. The possibility of the coexistence of HS and GS is very limited. Here we present the case of an elderly man with yellow skin and sclera recurring anaemia, and a final diagnosis of coexisting HS and GS.

The coincidence of beta-thalassemia and hereditary spherocytosis: A case report and literature review.

Key Clinical Message: When a person has both HS and beta-thalassemia, their clinical symptoms tend to be less severe. This is because these two conditions have contrasting features. If the clinical symptoms and laboratory results cannot be solely attributed to hemolytic anemia, it is important to consider the possibility of another form of hemolytic anemia coexisting. Abstract: We present a 26-year-old woman who has been experiencing abdominal pain, jaundice, and anemia for the past 15 years. Initially, she was diagnosed with gallstones and splenomegaly, but after a thorough hematology examination conducted by expert colleagues, it was discovered that she had both beta-thalassemia and hereditary spherocytosis. The osmotic fragility test confirmed this diagnosis. The patient was advised to undergo both splenectomy and cholecystectomy procedures. It is worth noting that the co-occurrence of these two conditions is rare.

Catalase, Glutathione Peroxidase, and Peroxiredoxin 2 in Erythrocyte Cytosol and Membrane in Hereditary Spherocytosis, Sickle Cell Disease, and ß-Thalassemia.

Catalase (CAT), glutathione peroxidase (GPx), and peroxiredoxin 2 (Prx2) can counteract the deleterious effects of oxidative stress (OS). Their binding to the red blood cell (RBC) membrane has been reported in non-immune hemolytic anemias (NIHAs). Our aim was to evaluate the relationships between CAT, GPx, and Prx2, focusing on their role at the RBC membrane, in hereditary spherocytosis (HS), sickle cell disease (SCD), ß-thalassemia (ß-thal), and healthy individuals. The studies were performed in plasma and in the RBC cytosol and membrane, evaluating OS biomarkers and the enzymatic activities and/or the amounts of CAT, GPx, and Prx2. The binding of the enzymes to the membrane appears to be the primary protective mechanism against oxidative membrane injuries in healthy RBCs. In HS (unsplenectomized) and ß-thal, translocation from the cytosol to the membrane of CAT and Prx2, respectively, was observed, probably to counteract lipid peroxidation. RBCs from splenectomized HS patients showed the highest membrane-bound hemoglobin, CAT, and GPx amounts in the membrane. SCD patients presented the lowest amount of enzyme linkage, possibly due to structural changes induced by sickle hemoglobin. The OS-induced changes and antioxidant response were different between the studied NIHAs and may contribute to the different clinical patterns in these patients.

Hemolysis during open heart surgery in patients with hereditary spherocytosis - systematic review of the literature and case study.

BACKGROUND: Due to the distinctive nature of cardiac surgery, patients suffering from hereditary spherocytosis (HS) are potentially at a high risk of perioperative complications resulting from hemolysis. Despite being the most prevalent cause of hereditary chronic hemolysis, the standards of surgical management are based solely on expert opinion. OBJECTIVE: We analyze the risk of hemolysis in HS patients after cardiac surgery based on a systematic review of the literature. We also describe a case of a patient with hereditary spherocytosis who underwent aortic valve repair. METHODS: This systematic review was registered in the PROSPERO international prospective register of systematic reviews (CRD42023417666) and included records from Embase, MEDLINE, Web of Science, and Google Scholar databases. The case study investigates a 38-year-old patient who underwent surgery for an aortic valve defect in mid-2022. RESULTS: Of the 787 search results, 21 studies describing 23 cases of HS undergoing cardiac surgery were included in the final analysis. Hemolysis was diagnosed in five patients (one coronary artery bypass graft surgery, two aortic valve bioprosthesis, one ventricular septal defect closure, and one mitral valve plasty). None of the patients died in the perioperative period. Also, no significant clinical hemolysis was observed in our patient during the perioperative period. CONCLUSIONS: The literature data show that hemolysis is not common in patients with HS undergoing various cardiac surgery techniques. The typical management of a patient with mild/moderate HS does not appear to increase the risk of significant clinical hemolysis. Commonly accepted beliefs about factors inducing hemolysis during cardiac surgery may not be fully justified and require further investigation.

Precise diagnosis of a hereditary spherocytosis patient with complicated hematological phenotype.

Hereditary spherocytosis (HS) is one of the most common causes of hereditary hemolytic anemia. The current diagnostic guidelines for HS are mainly based on a combination of physical examination and laboratory investigation. However, some patients present with complicated clinical manifestations that cannot be explained by routine diagnostic protocols. Here, we report a rare HS case of mild anemia with extremely high indirect bilirubin levels and high expression of fetal hemoglobin. Using whole exome sequencing analysis, this patient was identified as a heterozygous carrier of a de novo SPTB nonsense mutation (c.605G > A; p.W202*) and a compound heterozygous carrier of known UGT1A1 and KLF1 mutations. This genetic analysis based on the interpretation of the patient's genomic data not only achieved precise diagnosis by an excellent explanation of the complicated phenotype but also provided valuable suggestions for subsequent appropriate approaches for treatment, surveillance and prophylaxis.

Identification of a novel ANK1 gene variant c.1504-9G>A and its mechanism of intron retention in hereditary spherocytosis.

Objective: The objective of this study was to pinpoint pathogenic genes and assess the mutagenic pathogenicity in two pediatric patients with hereditary spherocytosis. Methods: We utilized whole-exome sequencing (WES) for individual analysis (case 1) and family-based trio analysis (case 2). The significance of the intronic mutation was validated through a Minigene splicing assay and supported by subsequent in vitro experiments. Results: Both probands received a diagnosis of hereditary spherocytosis. WES identified a novel ANK1 c.1504-9G>A mutation in both patients, causing the retention of seven nucleotides at the 5' end of intron 13, as substantiated by the Minigene assay. This variant results in a premature stop codon and the production of a truncated protein. In vitro studies indicated a reduced expression of the ANK1 gene. Conclusion: The novel ANK1 c.1504-9G>A variant is established as the causative factor for hereditary spherocytosis, with the c.1504-9G site functioning as a splicing receptor.

A Case Report of Hemolytic Hyponatremia.

Hereditary spherocytosis/elliptocytosis is a non-immune hemolytic anemia caused by an alteration in the erythrocyte membrane that predisposes the cell to its lysis. This report presents a case of a 42-year-old woman with a history of spontaneous abortion, associated with postpartum bleeding, chronic anemia, and premature menopause. After five years, she consulted due to alterations in the state of consciousness and severe symptomatic hyponatremia, with a diagnosis of hypopituitarism, explained by a late Sheehan syndrome. During hospitalization, she developed non-immune hemolytic anemia associated with a positive osmotic fragility test. A diagnosis of hereditary spherocytosis/elliptocytosis was made. We correlate blood hypoosmolarity as a trigger with the in vitro hypotonic solution of the osmotic fragility test for the diagnosis of this disease. This association is not reported in the literature; in our case, we show the concomitant improvement of anemia with the increase in sodium levels and hormonal replacement.

Severe hepatic sinusoidal obstruction syndrome in a patient with Wilms tumor and hereditary spherocytosis.

A 7-year-old girl with a history of splenectomy for hereditary spherocytosis (HS) was diagnosed with renal hematoma after a blunt abdominal trauma while receiving aspirin. Multiple erythrocyte transfusions and transarterial embolization were performed without success. Eventual nephrectomy revealed severely necrotic and perforated Stage III Wilms tumor (WT). Radiochemotherapy was administered, but by the eighth week, she developed severe hepatic sinusoidal obstruction syndrome (HSOS). Her ferritin level at the time was 3406 ng/ml. Defibrotide and aggressive supportive measures provided full recovery. The patient was given deferasirox for iron chelation therapy and finished her treatment without incident. To our knowledge, just one patient with HS and WT has been described in the literature. The role of iron excess in HSOS pathogenesis in non-transplant patients has not been addressed before either. Transfusional hyperferritinemia, in addition to chemotherapeutics and radiation, may have contributed to the development of severe HSOS in our patient.

Reticulocyte Antioxidant Enzymes mRNA Levels versus Reticulocyte Maturity Indices in Hereditary Spherocytosis, ß-Thalassemia and Sickle Cell Disease.

The antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and peroxiredoxin 2 (Prx2) are particularly important in erythroid cells. Reticulocytes and other erythroid precursors may adapt their biosynthetic mechanisms to cell defects or to changes in the bone marrow environment. Our aim was to perform a comparative study of the mRNA levels of CAT, GPX1, PRDX2 and SOD1 in reticulocytes from healthy individuals and from patients with hereditary spherocytosis (HS), sickle cell disease (SCD) and ß-thalassemia (ß-thal), and to study the association between their transcript levels and the reticulocyte maturity indices. In controls, the enzyme mRNA levels were significantly correlated with reticulocyte maturity indices for all genes except for SOD1. HS, SCD and ß-thal patients showed younger reticulocytes, with higher transcript levels of all enzymes, although with different patterns. ß-thal and HS showed similar reticulocyte maturity, with different enzyme mRNA levels; SCD and HS, with different reticulocyte maturity, presented similar enzyme mRNA levels. Our data suggest that the transcript profile for these antioxidant enzymes is not entirely related to reticulocyte maturity; it appears to also reflect adaptive mechanisms to abnormal erythropoiesis and/or to altered erythropoietic environments, leading to reticulocytes with distinct antioxidant potential according to each anemia.

Temporal trends of splenectomy in pediatric hospitalizations with hereditary spherocytosis from 2000 to 2019: A national survey.

BACKGROUND: Total and partial splenectomy are used in pediatric patients with hereditary spherocytosis to resolve anemia and hemolytic complications. PROCEDURE: Data from the Healthcare Cost and Utilization Project's Kid's Inpatient Database was used to profile and describe temporal trends in pediatric (≤18 years) hospital admissions in the United States from 2000 to 2019 data release years. Survey sampling methods were used to produce national estimates. RESULTS: From 2000 to 2019, the use of splenectomy declined overall, from 427 to 206 weighted procedures (difference = 222, 95% confidence interval [CI]: 124-320; p < .0001); the risk of undergoing splenectomy during admission also declined from 56.7% to 38.7% (risk difference = 17.9 percentage points [p.p.], 95% CI: 9.7-26.1; p < .0001). Total splenectomy was mostly used. Age at time of splenectomy increased 10.2 years (difference = 1.6 years, 95% CI: 0.6-2.7; p = .0018). The risk of splenectomy increased with age until 10 years, then leveled off until 18 years. The proportion of children aged ≤5 years undergoing splenectomy decreased from 27.7% to 11.2% in 2019 (risk difference: 16.5 p.p., 95% CI: 7.3-25.7; p = .0004). The strongest clinical predictors of splenectomy, adjusting for patient- and hospital-level characteristics, were a co-diagnosis of symptomatic cholelithiasis (adjusted odds ratio [aOR] = 3.18, 95% CI: 1.92-5.28; p < .0001) and splenomegaly or hypersplenism (aOR = 2.52, 95% CI: 1.74-3.65; p < .0001). Risk of splenectomy with splenomegaly or hypersplenism increased over time. CONCLUSION: Splenectomy was delayed until age greater than 10 years. Older age, co-diagnosis with splenomegaly or hypersplenism, or symptomatic cholelithiasis were strongest clinical predictors of splenectomy. Conservative management of hereditary spherocytosis appears to be more common.

Novel mutation in alpha-spectrin gene in Saudi patients with hereditary spherocytosis.

Hereditary spherocytosis (HS) is the most common hereditary hemolytic disorder induced by red blood cell (RBC) membrane defect. This study was undertaken to determine mutations in genes associated with RBC membrane defect in patients with HS such as α-spectrin gene (SPTA1), ß-spectrin gene (SPTB), ankyrin gene (ANK1), band 3 anion transport gene (SLC4A1) and erythrocyte membrane protein band 4.1 gene (EPB41). Blood samples were collected from 23 unrelated patients with HS. Patients were diagnosed according to the guidelines from the British Society for Hematology. All hematological examinations for the determination of RBC abnormalities and osmotic fragility tests were conducted. Genomic DNA were extracted from peripheral blood cells and coding exons of known genes for hereditary spherocytosis were enriched using Roche/KAPA sequence capture technology and sequenced on an Illumina system via next-generation sequencing (NGS). The data showed that most of the HS patients confirmed splenomegaly and showed elevated reticulocytes and abnormal bilirubin values. NGS analysis identified the heterozygous variant c.5501G > A in the exon 39 of SPTA1 gene, resulted in a Trp1834*, which leads to a premature stop codon and subsequent mRNA degradation (nonsense- mediated decay) or truncation in α spectrin. Moreover, our data also revealed conventional mutations in genes SPTB, ANK, SLC4A1 and EBP41 in severe patients of HS. In short, this is the first report that determined a novel mutation c.5501G > A in SPTA1 gene in the Saudi population. To the best of our knowledge, this variant c.5501G > A has not been described in global literature so far. This novel mutation in SPTA1 gene is unique in the Saudi population.

The Correlation Between Clinical Phenotype and Genotype of Hereditary Spherocytosis.

Objective: Hereditary spherocytosis (HS) is a common hereditary hemolytic disease. This study aimed to explore the correlation between the phenotype and mutant genotype of HS to improve the clinical understanding of HS. Methods: This study reported a case of spontaneous mutation of the ANK1 gene in HS, reviewed previous studies on the genotype-phenotype correlation of HS, statistically analyzed the main types of gene mutations in HS, and summarized the clinical data of patients. Results: This patient had clinical manifestations of anemia, splenomegaly, peripheral blood smear with increased spherocytosis, and bilirubin, confirmed as ANK1 gene mutant HS by gene detection. In addition, this study included 14 previous studies on genotype-phenotype correlation, collected data, and determined that the ANK1 and SPTB genes were the most common types of gene mutations in HS patients. The mutant HS of the ANK1 gene would lead to lower hemoglobin levels. Conclusion: The results of this study showed that ANK1 and SPTB were the most common types of gene mutations in HS patients. Compared with patients with the SPTB genotype HS, patients with ANK1 mutant HS had more severe extravascular hemolysis, and a higher proportion needed splenectomy in early childhood.

Molecular characteristics of hereditary red blood cell membrane disorders in Thailand: a multi-center registry.

Red blood cell (RBC) membrane disorders represent a significant category of hereditary hemolytic anemia; however, information from Southeast Asia is limited. We established a national registry aiming to characterize RBC membrane disorders and their molecular features in Thailand. A total of 100 patients (99 kindreds) diagnosed with RBC membrane disorders between 2011 and 2020 from seven university hospitals were enrolled. The most prevalent disorders observed were hereditary elliptocytosis (HE; n=33), hereditary pyropoikilocytosis (HPP; n=28), hereditary spherocytosis (HS; n=19), Southeast Asian ovalocytosis (SAO; n=10 of 9 kindreds), and two cases of homozygous SAO. The remaining cases were grouped as unclassified membrane disorder. Seventy-six patients (76%) were molecularly confirmed by PCR, direct DNA sequencing, or hi-throughput sequencing. The primary causative gene for HE and HPP was SPTB, accounting for 28 out of 29 studied alleles for HE and 56 of 56 studied alleles for HPP. In the case of HS, dominant sporadic mutations in the ANK1 gene (n=4) and SPTB gene (n=3) were identified as the underlying cause. Notably, the four most common variants causing HE and HPP were SPTB Providence (c.6055 T>C), SPTB Buffalo (c.6074 T>G), SPTB Chiang Mai (c.6224 A>G), and SPTB c.6171__82delins TGCCCAGCT. These recurrent SPTB mutations accounted for 79 out of 84 mutated SPTB alleles (94%). In summary, HE and hereditary HPP associated with recurrent SPTB mutations are the predominant types of RBC membrane disorders observed in Thailand. These findings have significant implications for the clinical management and future research of RBC membrane disorders in the region.