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.

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.

Identification of the molecular etiology in rare congenital hemolytic anemias using next-generation sequencing with exome-based copy number variant analysis.

OBJECTIVES: In congenital hemolytic anemias (CHA), it is not always possible to determine the specific diagnosis by evaluating clinical findings and conventional laboratory tests. The aim of this study is to evaluate the utility of next-generation sequencing (NGS) and clinical-exome-based copy number variant (CNV) analysis in patients with CHA. METHODS: One hundred and forty-three CHA cases from 115 unrelated families referred for molecular analysis were enrolled in the study. Molecular analysis was performed using two different clinical exome panels in 130 patients, and whole-exome sequencing in nine patients. Exome-based CNV calling was incorporated into the traditional single-nucleotide variant and small insertion/deletion analysis pipeline for NGS data in 92 cases. In four patients from the same family, the PK Gypsy variant was investigated using long-range polymerase chain reaction. RESULTS: Molecular diagnosis was established in 86% of the study group. The most frequently mutated genes were SPTB (31.7%) and PKLR (28.5%). CNV analysis of 92 cases revealed that three patients had different sizes of large deletions in the SPTB and six patients had a deletion in the PKLR. CONCLUSIONS: In this study, NGS provided a high molecular diagnostic rate in cases with rare CHA. Analysis of the CNVs contributed to the diagnostic success.

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.

Next generation sequencing (NGS) interest in deciphering erythrocyte molecular defects' association in red cell disorders: Clinical and erythrocyte phenotypes of patients with mutations inheritance in PIEZO1, Spectrin ß1, RhAG and SLC4A1.

We report here an instructive case referred at 16 months-old for exploration of hemolysis without anemia (compensated anemia with reticulocytosis). The biology tests confirmed the hemolysis with increased total and indirect bilirubin. The usual hemolysis diagnosis tests were normal (DAT, G6PD, PK, Hb electrophoresis) except cytology and ektacytometry suggesting an association of multiple red blood cell (RBC) membrane disorders. This led us to propose a molecular screening analysis using targeted-Next Generation Sequencing (t-NGS) with a capture technique on 93 genes involved in RBC and erythropoiesis defects. We identified 4 missense heterozygous allelic variations, all of them were described without any significance (VUS) in the SLC4A1, RhAG, PIEZO1 and SPTB genes. The study of the familial cosegregation and research functional tests allowed to decipher the role of at least two by two genes in the phenotype and the hemolytic disease of this young patient. Specialized t-NGS panel (or virtual exome/genome sequencing) in a disease-referent laboratory and the motivated collaboration of clinicians, biologists and scientists should be the gold standard for improving the diagnosis of the patients affected with RBC diseases or rare inherited anemias.

Identification of variants in 94 Chinese patients with hereditary spherocytosis by next-generation sequencing.

Hereditary spherocytosis (HS) is the most common type of hereditary erythrocyte membrane disease and has varied phenotypic features and genetic patterns. We herein performed a retrospective study of 94 patients with HS and aimed to investigate the genetic variations and genotype-phenotype correlations using targeted next-generation sequencing. In 79/94 (84%) patients, 83 HS variants including 67 novel variants were identified. Pathogenic variants of SPTB, ANK1, SLC4A1, SPTA1, and EPB42 were found in 32/79(41%), 22/79(28%), 15/79 (19%), 8/79 (9%), and 3/79 (4%) of the patients respectively, revealing that SPTB is the most frequently mutated HS gene in Eastern China. Most SPTB and ANK1 gene variations were nonsense and frameshift variations. Missense variants were the main variant type of SLC4A1, SPTA1, and EPB42 genes. Interestingly, one SPTA1 variant (p. Arg1757Cys) showed an autosomal dominant inheritance pattern and one EPB42 variant (p. Gln377His) was apparent as a hotspot variation. Furthermore, genotype-phenotype analysis was performed among the five mutated gene groups. Besides the finding that patients with the SLC4A1 variant had the highest mean corpuscular hemoglobin levels, no clear correlations between genotype and phenotype were observed.

Hereditary Spherocytosis: Can Next-Generation Sequencing of the Five Most Frequently Affected Genes Replace Time-Consuming Functional Investigations?

Congenital defects of the erythrocyte membrane are common in northern Europe and all over the world. The resulting diseases, for example, hereditary spherocytosis (HS), are often underdiagnosed, partly due to their sometimes mild and asymptomatic courses. In addition to a broad clinical spectrum, this is also due to the occasionally complex diagnostics that are not available to every patient. To test whether next-generation sequencing (NGS) could replace time-consuming spherocytosis-specific functional tests, 22 consecutive patients with suspected red cell membranopathy underwent functional blood tests. We were able to identify the causative genetic defect in all patients with suspected HS who underwent genetic testing (n = 17). The sensitivity of the NGS approach, which tests five genes (ANK1 (gene product: ankyrin1), EPB42 (erythrocyte membrane protein band4.2), SLC4A1 (band3), SPTA1 (α-spectrin), and SPTB (ß-spectrin)), was 100% (95% confidence interval: 81.5-100.0%). The major advantage of genetic testing in the paediatric setting is the small amount of blood required (<200 µL), and compared to functional assays, sample stability is not an issue. The combination of medical history, basic laboratory parameters, and an NGS panel with five genes is sufficient for diagnosis in most cases. Only in rare cases, a more comprehensive functional screening is required.

A novel SPTB mutation causes hereditary spherocytosis via loss-of-function of ß-spectrin.

Hereditary spherocytosis (HS) is the most frequently observed chronic non-immune hemolytic disorder caused by altered red cell membrane function. SPTB gene mutation is one of the most common causes of HS, but pathogenicity analyses and pathogenesis research on these mutations have not been widely conducted. In this study, a novel heterozygous mutation of the SPTB gene (c.1509_1518del; p.K503Nfs*67) was identified in a Chinese family with HS by whole-exome sequencing (WES) and was then confirmed by Sanger sequencing. Next, the pathogenicity and pathogenesis of this mutation were studied using peripheral blood. We found that this mutation disrupted the synthesis and localization of ß-spectrin and weakened the interaction between ß-spectrin and ankyrin, which may be caused by the nonsense-mediated mRNA degradation pathway. These changes lead to the transformation of discoid erythrocytes into spherocytes, resulting in hemolytic anemia. Therefore, we classified this novel mutation as a pathogenic mutation leading to loss-of-function of ß-spectrin. It would be insightful to perform the same mutation test and to provide genetic counseling to other relatives of the proband. Our study increases the current understanding of the molecular mechanisms related to mutations in SPTB.

New ultrasonographic midtrimester scoring method for predicting spontaneous preterm birth in uncomplicated asymptomatic twin pregnancies.

OBJECTIVES: The aim of the present study was to evaluate a new ultrasonographic scoring method that could predict spontaneous preterm birth (sPTB) in uncomplicated twin pregnancies during routine anomaly screening in the midtrimester. METHODS: This prospective study included women with a monochorionic diamniotic (MCDA) or dichorionic diamniotic (DCDA) twin pregnancy gestational ages from 170/7 through 226/7. A new ultrasonographic score between 0 and 5 points was calculated using cervical length (CL), uterocervical angle (UCA), and cervical dilatation status during routine anomaly screening in the midtrimester. The primary outcome of the study was the prediction of sPTB < 32 and <34 gestational weeks. RESULTS: A total of 118 pregnant women with twins were evaluated, 31 of whom delivered before 34 gestational weeks an 87 of whom delivered after 34 gestational weeks. The sensitivity and specificity values were separately calculated for scores of 3.5 and 2.5 for predicting sPTB < 32 gestational weeks. The cut-off value of 3.5 provided a sensitivity of 80% and a specificity of 82%. When the score was 2.5, the sensitivity and specificity were 86 and 71%, respectively. To determine a score for predicting sPTB < 34 gestational week cut-off value of 3.5 provided a sensitivity of 80% and a specificity of 90%. When the score value was 2.5, the sensitivity and specificity of the method were 83 and 81%, respectively. CONCLUSIONS: Our results indicated that the midtrimester new scoring is a simple technique that can be easily used as an improved tool for predicting the risk of sPTB in women with a twin pregnancy.

Identification of a novel heterozygous SPTB mutation by whole genome sequencing in a Chinese patient with hereditary spherocytosis and atrial septal defect: a case report.

BACKGROUND: Hereditary spherocytosis (HS) is a common inherited red blood cell membrane disorder characterized by an abnormal increase of spherocytes in peripheral blood. SPTB gene mutation is one of the most common causes of HS; however, few cases of HS resulting from SPTB mutation in the Chinese population have been reported so far. CASE PRESENTATION: A 3-year-old Chinese girl presented to Qingdao Women and Children's Hospital, Qingdao University, with atrial septal defect (ASD). Meanwhile, she was clinically diagnosed with HS. Whole genome sequencing (WGS) was performed for the proband and her parents for genetic molecular analysis. A novel SPTB mutation (c.1756delG) was detected by WGS and confirmed by Sanger sequencing in the proband. This mutation results in a frameshift with a premature termination codon in exon 12, leading to a nonsense mutation (p.Ala586Profs*7). Her parents had no similar symptoms, and blood routine and serum biochemical tests showed no significant abnormalities. The patient's mother did not know of any relatives with HS-like symptoms. Percutaneous transcatheter closure was successfully performed for treating the ASD. CONCLUSION: In this study, we identified a novel SPTB frameshift mutation in a Chinese girl with HS. This finding would expand the spectrum of SPTB mutations, provide a valuable insight into the genotyping of HS in the Chinese population, and contribute to the clinical management and genetic counseling in HS.

Whole exome sequencing identified a novel mutation (p.Ala1884Pro) of ß-spectrin in a Chinese family with hereditary spherocytosis.

BACKGROUND: Hereditary spherocytosis (HS) is an inherited disorder of erythrocyte. The typical feature of HS is the presence of spherical-shaped erythrocytes on the peripheral blood smear. According to previous studies, more than five candidate genes, such as ANK1, SPTB, SPTA1, SLC4A1 and EPB42 have been identified in HS patients. METHODS: In the present study, a Chinese HS family was investigated. The proband suffered from pathologic jaundice and splenomegaly. A blood test and peripheral blood smear experiment further confirmed the diagnosis of HS. We selected the proband to perform the whole exome sequencing. RESULTS: After data filtering and co-segregation analysis, we identified 12 mutations in affected members that were absent in healthy members. In consideration of the inheritance pattern, Online Mendelian Inheritance in Man clinical phenotypes, Toppgene function and American College of Medical Genetics classification, we considered the novel mutation (c.5650G > C/p.Ala1884Pro) of ß-spectrin (SPTB) to be the genetic lesion in this family. The novel mutation, resulting in a substitution of alanine by proline, may lead to transformation of the SPTB protein structure, which affects the binding between SPTB and ankyrin. CONCLUSIONS: The present study confirmed the hereditary red blood cell membrane disorders at a molecular level and expanded the spectrum of SPTB mutations. This may contribute to the clinical management and genetic counseling with respect to HS.

Low dose aspirin in the prevention of recurrent spontaneous preterm labour - the APRIL study: a multicenter randomized placebo controlled trial.

BACKGROUND: Preterm birth (birth before 37 weeks of gestation) is a major problem in obstetrics and affects an estimated 15 million pregnancies worldwide annually. A history of previous preterm birth is the strongest risk factor for preterm birth, and recurrent spontaneous preterm birth affects more than 2.5 million pregnancies each year. A recent meta-analysis showed possible benefits of the use of low dose aspirin in the prevention of recurrent spontaneous preterm birth. We will assess the (cost-)effectiveness of low dose aspirin in comparison with placebo in the prevention of recurrent spontaneous preterm birth in a randomized clinical trial. METHODS/DESIGN: Women with a singleton pregnancy and a history of spontaneous preterm birth in a singleton pregnancy (22-37 weeks of gestation) will be asked to participate in a multicenter, randomized, double blinded, placebo controlled trial. Women will be randomized to low dose aspirin (80 mg once daily) or placebo, initiated from 8 to 16 weeks up to maximal 36 weeks of gestation. The primary outcome measure will be preterm birth, defined as birth at a gestational age (GA) < 37 weeks. Secondary outcomes will be a composite of adverse neonatal outcome and maternal outcomes, including subgroups of prematurity, as well as intrauterine growth restriction (IUGR) and costs from a healthcare perspective. Preterm birth will be analyzed as a group, as well as separately for spontaneous or indicated onset. Analysis will be performed by intention to treat. In total, 406 pregnant women have to be randomized to show a reduction of 35% in preterm birth from 36 to 23%. If aspirin is effective in preventing preterm birth, we expect that there will be cost savings, because of the low costs of aspirin. To evaluate this, a cost-effectiveness analysis will be performed comparing preventive treatment with aspirin with placebo. DISCUSSION: This trial will provide evidence as to whether or not low dose aspirin is (cost-) effective in reducing recurrence of spontaneous preterm birth. TRIAL REGISTRATION: Clinical trial registration number of the Dutch Trial Register: NTR 5675 . EudraCT-registration number: 2015-003220-31.

Polymorphism of the ADRB2 Rs1042713 Gene is not Associated with Spontaneous Preterm Birth: Analyses in a Slovenian Sample and Meta Analysis.

The ß-2-adrenergic receptor (ADRB2) gene has an important impact on smooth muscle relaxation, including the smooth muscles of the uterus. The results of previously published studies of the association between the ADRB2 rs1042713 polymorphism and spontaneous preterm birth (SPTB) were inconsistent. We evaluated the association between ADRB2 and SPTB in a case-control association study in a Slovenian sample population and performed a meta analysis of previously published studies. No association was found between the polymorphism in the ADRB2 gene and SPTB in the Slovenian sample of 98 SPTB patients and 135 controls under dominant [χ2 = 0.01, p = 0.92, odds ratio (OR) = 1.03, 95% confidence interval (95% CI) = 0.52-2.04), recessive (χ2 = 0.01, p = 0.92, OR = 0.98, 95% CI = 0.57-1.70) and codominant genetic models (χ2 = 0.01, p = 0.92, OR = 0.99, 95% CI = 0.59-1.68). The meta analysis of a pooled sample of 404 SPTB patients and 878 controls suggested no association of ADRB2 polymorphism and SPTB under dominant (OR = 1.12, 95% CI = 0.81-1.54) and recessive genetic models (OR = 0.84, 95% CI = 0.64-1.12). These findings suggest no association between the ADRB2 rs1042713 gene polymorphism and SPTB. Further association studies with larger sample sizes are needed.

Mutational characteristics of ANK1 and SPTB genes in hereditary spherocytosis.

The aim of this study was to describe the mutational characteristics in Korean hereditary spherocytosis (HS) patients. Relevant literatures including genetically confirmed cases with well-documented clinical summaries and relevant information were also reviewed to investigate the mutational gene- or domain-specific laboratory and clinical association. Twenty-five HS patients carried one heterozygous mutation of ANK1 (n = 13) or SPTB (n = 12) but not in SPTA1, SLC4A1, or EPB42. Deleterious mutations including frameshift, nonsense, and splice site mutations were identified in 91% (21/23), and non-hotspot mutations were dispersed across multiple exons. Genotype-phenotype correlation was clarified after combined analysis of the cases and the literature review; anemia was most severe in HS patients with mutations on the ANK1 spectrin-binding domain (p < 0.05), and SPTB mutations in HS patients spared the tetramerization domain in which mutations of hereditary elliptocytosis and pyropoikilocytosis are located. Splenectomy (17/75) was more frequent in ANK1 mutant HS (32%) than in HS with SPTB mutation (10%) (p = 0.028). Aplastic crisis occurred in 32.0% of the patients (8/25; 3 ANK1 and 5 SPTB), and parvovirus B19 was detected in 88%. The study clarifies ANK1 or SPTB mutational characteristics in HS Korean patients. The genetic association of laboratory and clinical aspects suggests comprehensive considerations for genetic-based management of HS.

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.

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.

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.

[Genetic Analysis of a Chinese Pedigree with Hereditary Spherocytosis Caused by Copy Number Variation Deletion of SPTB Gene].

OBJECTIVE: To investigate the molecular mechanism of the disease based on the clinical characterization and genetic mutation analysis in a family with hereditary spherocytosis. METHODS: The proband with jaundice and anemia was referred to Yidu Central Hospital of Weifang in May 2021. Peripheral blood samples were collected from six members of the family. Second-generation sequencing was used to screen the pathological mutations, and the clinically significant variant sites were selected. Then the relevant databases were used to analyze the variant sites, and RT-qPCR was used to detect the relative mRNA levels of candidate gene. The structure and function of SPTB protein were analyzed by UniProt and SMART databases. RESULTS: We infer that the SPTB gene copy number variation (CNV) deletion was co-segregated with the phenotype of the patients in this family based on the results of second-generation sequencing (about 700 target genes). The UCSC Genome Browser demonstrated that the deleted region was mainly located in exon2-3 of SPTB gene. The results of RT-qPCR showed that the relative SPTB mRNA levels of all patients were lower than the healthy control. UniProt and SMART databases analysis showed that SPTB protein without CH1 and CH2 domains could not bind to erythrocyte membrane actin. CONCLUSION: The CNV deletion of SPTB gene may be the reason for the hereditary spherocytosis in this family.

Case report: Whole-exome sequencing for a hereditary elliptocytosis case with an unexpectedly low HbA1c.

Objectives: Hereditary elliptocytosis is a group of erythroid hereditary diseases characterized by elliptically shaped erythrocytes in peripheral blood. It is mainly inherited through autosomal dominant inheritance. This study aimed to conduct a genetic etiology analysis in a case with a clinical diagnosis of hereditary elliptocytosis and an unexpectedly low HbA1c. Methods: Whole-exome sequencing was performed to find the possible pathogenic mutations. At the same time, bioinformatics software was used to predict the mutation function. Sanger sequencing was performed to verify the suspected pathogenic mutations. Results: Whole-exome sequencing results showed that the proband with mild anemia had a heterozygous c.2303G>A (p.G768D) missense mutation in the 13th exon of the SPTB gene. The Sanger sequencing confirmed this heterozygous mutation. This mutation was extremely rare in the population, and multiple software's predictions were harmful. Conservative analysis revealed that this site was highly conserved in various species. Conclusion: The c.2303G>A mutation of the SPTB gene is the suspected cause of hereditary elliptocytosis in the patient. Our data show that microscopic examination of red blood cells on blood smears is an important means of diagnosing hereditary elliptocytosis. Whole-exome sequencing is an effective tool to determine the genetic etiology of erythrocyte membrane diseases, which can promote accurate diagnosis and genetic counseling.

Case report: Genetic analysis of a novel intronic inversion variant in the SPTB gene associated with hereditary spherocytosis.

Background: Hereditary spherocytosis (HS) is a congenital haemolytic anaemia attributed to dysregulation or abnormal quantities of erythrocyte membrane proteins. Currently, the most common erythrocytic gene, spectrin ß (SPTB), variants are located in exons and give rise to mRNA defects. However, the genetic characteristics and pathogenic mechanisms of SPTB intronic variants are not completely understood. This study aimed to analyse a rare intronic inversion variant in the SPTB gene associated with HS, and explore the impact of the variant on SPTB mRNA splicing. Method: The clinical manifestations of the patient were summarised and analysed for spherocytosis phenotype diagnosis. The pathogenic variant was identified in the proband using targeted next-generation and Sanger sequencing. RNA sequencing was performed to analyse whether SPTB gene splicing and expression were affected. Results: Targeted next-generation sequencing identified a novel disease-associated intronic inversion variant of the SPTB gene in the proband. The inversion variant was located between intron 19 and 20, and contained the entire exon 20 and partial sequences of adjacent introns. Sanger sequencing confirmed that the intronic inversion variant only appeared in the genome of the proband, not in his parents. RNA sequencing revealed that the variant could result in the skipping of exon 20 and reduced expression of SPTB mRNA. Conclusion: This study identifies a rare intronic inversion variant in the SPTB gene associated with hereditary spherocytosis. The pathogenic variant can lead to exon 20 skipping and decreased SPTB gene expression. This finding has not been previously reported in any literature. This study can expand the intronic variant spectrum of the SPTB gene, deepen our understanding of HS pathogenesis, and contribute to the genetic diagnosis and clinical management of patients.