Hereditary spherocytosis: evaluation of 68 children

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), β-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.

Clinical Characteristics and Treatment Outcome of Hereditary Spherocytosis: A Single Center's Experience

Objectives

The objective of the study is to present the demographic characteristics, clinical and laboratory features and outcome of our patients with hereditary spherocytosis (HS).

Methods

Demographic, clinical, and laboratory data; complications; and splenectomy results were analyzed retrospectively. The severity of the disease was scaled according to Eber's criteria.

Results

Sixty-nine patients (42 boys, 27 girls, median age: 3 years) were eligible. Sixty-eight percent of the patients had a history of neonatal jaundice. The complaints at admission were jaundice (71%), fatigue (27.5%), fainting (4.3%), and pallor (4.3%). The median follow-up duration was 8.5 years. According to Eber's criteria, three (4.3%), 57 (82.6%), and nine (13.1%) patients had mild, moderate, and severe diseases, respectively. Thirty-six patients (52.1%) had a splenectomy. Following splenectomy, we observed a significant rise in hemoglobin levels and a decline in indirect bilirubin levels. Post-operative thrombocytosis was common, with a tendency to fall and stabilize after 1 month. There were no thromboembolic complications.

Conclusion

In spite of the high rate of consanguinity, familial history of HS, and neonatal jaundice in our study group, the majority of the HS patients were identified relatively late, about 3 years. This finding shows that HS might be insufficiently acknowledged by primary care. Splenectomy, in selected cases, may reduce the need for transfusions. Post-splenectomy transient thrombocytosis is common and has a benign course.

Clinical Features and Outcome of Children With Hereditary Spherocytosis

OBJECTIVE

The aim of this study was to evaluate the demographics, clinical, and laboratory findings and treatment responses of patients with hereditary spherocytosis (HS).

MATERIALS AND METHODS

Data of children with HS were examined. Diagnosis was based on clinical history, physical examination, family history, presence of spherocytes on peripheral blood smear, and osmotic fragility test.

RESULTS

A total of 101 patients were included. The median (range) age at diagnosis was 38.0 (1 to 188) months. Mild, moderate, and severe forms of HS were present in 29 (28.7%), 15 (14.9%), and 57 (56.4%) patients, respectively. Family history was available in 73 patients and 56 of these (76.7%) had a positive family history for HS. Forty-five (44.5%) patients needed regular transfusions and all of these had severe disease. Although most patients did not require transfusion postsplenectomy, 2 of 45 (4.4%) patients continued to require transfusion. Transfusion dependence was significantly (P<0.001) higher in patients with severe spherocytosis.

CONCLUSIONS

In HS, splenomegaly, pallor, and jaundice are the most common clinical features. Splenectomy dramatically reduces hemolysis in most cases and virtually abolishes further requirement for transfusion.

Use of Complete Blood Cell Count Components to Screen for Hereditary Spherocytosis in Neonates

BACKGROUND AND OBJECTIVES

The neonatal hereditary spherocytosis (HS) index, defined as the mean corpuscular hemoglobin concentration divided by the mean corpuscular volume, has been proposed as a screening tool for HS in neonates. In a population of mostly white infants, an HS Index >0.36 was 97% sensitive and >99% specific. We evaluated the utility of the HS Index among a more racially and ethnically diverse population and determined if its discrimination varies with total serum bilirubin (TSB) levels.

METHODS

Infants born at ≥35 weeks' gestation at 15 Kaiser Permanente Northern California hospitals from 1995 to 2015 were eligible (N = 670 272). Erythrocyte indices from the first complete blood count drawn at ≤7 days and TSB levels drawn at ≤30 days were obtained. Diagnoses of HS were confirmed via chart review.

RESULTS

HS was confirmed in 79 infants, 1.2 per 10 000. HS was more common among infants of white and "other" race or ethnicity and among those with higher peak TSB levels. The area under the receiver operating characteristic curve for the HS Index was 0.84 (95% confidence interval 0.78-0.90). Likelihood ratios ranged from 10.1 for an HS Index ≥0.380 to 0.1 for an HS Index <0.310. Dichotomized at 0.36, the HS Index was 56% sensitive and 93% specific. Discrimination of the HS Index appeared best among infants with TSB levels <10 mg/dL.

CONCLUSIONS

The HS Index, when obtained from a CBC drawn within the first week after birth, had only modest ability to alter the probability of HS.

Clinical manifestation and phenotypic analysis of novel gene mutation in 28 Chinese children with hereditary spherocytosis

Purpose

Objective to summarize the clinical features and laboratory findings of 28 Chinese children with hereditary spherocytosis (HS), and analyze these mutations.

Method

Collected and analyzed the clinical data of all children and their parents, and completed the relevant laboratory examinations of all children. Analyzed the sequence of related genes by second‐generation sequencing technology, and verified the suspected mutations by Sanger sequencing method. Analyzed all biological information using the Single Nucleotide Polymorphism database, the 1000 Human Genome Project, and the Exosome Aggregation Consortium.

Result

New mutations were detected in the HS coding region of 28 children. Among them, there were 13 cases (46.4%) with ANK1 mutation, 10 cases (35.7%) with SPTB mutation, three cases (10.7%) with SLC4A1 mutation, and two cases (7.2%) with SPTA1 mutation. All mutations cause amino acid changes in the coding gene, as well as subsequent changes in protein structure or loss of function.

Conclusion

All the newly discovered gene coding region mutation sites detected are the suspected pathogenic causes of the 28 Chinese children. At the same time, the second‐generation gene sequencing technology is an effective means to diagnose HS. Different mutation types and different mutation regions have no significant correlation with the severity of anemia. The novel gene mutation sites in 28 children studied in this paper have not yet been included in the human genome database, dbSNP (v138), or ExAC database. The new gene mutations found in HS children can provide a theoretical basis for further exploring the genetic causes of HS in Chinese children.

[Comparison of hemolytic characteristics among paroxysmal nocturnal hemoglobinuria, autoimmune hemolytic anemia and hereditary spherocytosis]

目的

确定在阵发性睡眠性血红蛋白尿症（PNH）、自身免疫性溶血性贫血（AIHA）与遗传性球形红细胞增多症（HS）鉴别诊断中有重要参考价值的溶血特征。

方法

比较1998年1月至2017年4月108例经典型PNH患者、127例AIHA患者与172例HS患者的临床表现和溶血特征。

结果

①网织红细胞比例（Ret%）：PNH患者Ret%[6.70%（0.14%~22.82%）]明显低于AIHA患者[14.00%（0.10%~55.95%），z=7.101，P<0.001]和HS患者[11.83%（0.60%~57.39%），z=8.477，P<0.001]。轻度贫血时，PNH与AIHA患者Ret%水平差异无统计学意义，AIHA患者Ret%水平低于HS患者[7.63%（1.87%~29.20%）对11.20%（3.31%~22.44%），z=−2.165，P=0.030]。中、重度贫血时，PNH患者Ret%水平均显著低于AIHA和HS患者。②总胆红素（TBIL）：HS患者TBIL水平为79.3（11.2~244.0）µmol/L，显著高于AIHA患者[57.6（7.6~265.0）µmol/L]与PNH患者[26.2（4.6~217.7）µmol/L]（z值分别为5.469、−2.165，P值均<0.001）；HS患者TBIL超过4倍正常值上限比例（64.1%）明显高于AIHA患者（37.7%，χ²=19.896，P<0.001）和PNH患者（4.6%，P<0.001）。③LDH：PNH患者LDH水平为1 500（216~5 144）U/L，显著高于AIHA患者[487（29~3 516）U/L]与HS患者[252（132~663）U/L]（z值分别为−9.556、−11.518，P值均<0.001）；79.1%的PNH患者LDH水平>1 000 U/L，明显高于AIHA患者（13.0%，χ²=93.748，P<0.001）和HS患者（0，P<0.001）。④脾大：43.5%的PNH患者脾大，中、重度脾大者占16.0%；而98.6%的AIHA患者和100.0%的HS患者脾大（P<0.001），中、重度脾大者分别占63.0%（P<0.001）和90.4%（P<0.001）。⑤胆囊结石：43.1%的HS患者合并胆囊结石，明显高于AIHA患者（10.5%，P<0.001）与PNH患者（2.9%，P<0.001）。

结论

综合评估Ret%、TBIL、LDH水平、脾大及胆囊结石这五项溶血特征，可以清晰地倾向性判断PNH、AIHA和HS，并为下一步进行特异性实验室检查确诊提供可靠的诊断思路。这种综合评估简单、实用、有效，具有重要的临床意义。

The hemostasis system in children with hereditary spherocytosis

INTRODUCTION

Patients with hereditary spherocytosis (HS) are characterized by having an increased risk for thrombosis. An early manifestation of thrombotic complications can occur even in childhood, especially after surgery. Hypercoagulability can be associated with hemolytic crises.

AIM

The aim of this study was to investigate the hemostatic state in children with HS using global hemostasis assays.

METHODS

The hemostatic status of 62 children (38 boys and 24 girls; age range: 0.5 to 17 years) with HS during and without hemolytic crisis was assessed using clotting times (APTT, TT, and PR), fibrinogen and D-dimer levels, and global hemostasis, thromboelastography (TEG) and thrombodynamics (TD) assays. One hundred and two healthy children undergoing annual medical examination were enrolled as a control group.

RESULTS

TEG and TD parameters were increased in the children with HS compared to the control group (60 ± 5 mm vs. 53 ± 4 mm, p < 0.05 for TEG maximum amplitude; 28 ± 3 μm/min vs. 24 ± 2 μm/min, p < 0.05 for TD clot growth rate), while APTT, TT and PR were not significantly different between the two groups. Patients with HS were divided into 2 groups: those during hemolytic crisis (28 patients) and those without hemolytic crisis (34 patients). TEG and TD parameters were increased in those during hemolytic crisis compared to the steady state HS group (62 ± 5 mm vs. 57 ± 4 mm, p < 0.05 for TEG maximum amplitude; 31 ± 4 μm/min vs. 26 ± 3 μm/min, p < 0.05 for TD clot growth rate). The D-dimer levels were increased in 4 HS patients, for whom the activation of blood clotting was noted. Fibrinogen levels were decreased in patients with HS compared to the control group (2.1 ± 0.4 mg/ml vs. 2.6 ± 0.4 mg/ml, p < 0.05). Other tests were within the reference ranges for both groups.

CONCLUSIONS

The global hemostasis tests TEG and TD revealed hypercoagulability in patients with HS. More dramatic changes were observed in patients experiencing a hemolytic crisis.

Mean corpuscular volume of control red blood cells determines the interpretation of eosin-5'-maleimide (EMA) test result in infants aged less than 6 months

Eosin-5′-maleimide (EMA) binding test is a flow cytometric test used to detect hereditary spherocytosis (HS). To perform the test sample from patients, 5–6 reference samples of red blood are needed. Our aim was to investigate how the mean corpuscular volume (MCV) of red blood cells influences on the value of fluorescence of bounded EMA dye and how the choice of reference samples affects the test result. EMA test was performed in peripheral blood from 404 individuals, including 31 children suffering from HS. Mean fluorescence channel of EMA-RBCs was measured with Cytomics FC500 flow cytometer. Mean corpuscular volume of RBCs was assessed with LH750 Beckman Coulter. Statistical analysis was performed using Graph Pad Prism. The correlation Spearman coefficient between mean channel of fluorescence of EMA-RBCs and MCV was r = 0.39, p < 0.0001. Interpretation of EMA test depends on MCV of the reference samples. If reference blood samples have lower MCV than the patients MCV, EMA test result might be negative. Due to different MCV values of RBCs in infancy and ca. Three months later, EMA test in neonates might be interpreted falsely negative. Samples from children younger than 3 months old had EMA test result 86.1 ± 11.7 %, whereas same samples that analyzed 4.1 ± 2.1 later had results of 75.4 ± 4.5 %, p < 0.05. Mean fluorescence of EMA-bound RBC depends on RBC’s volume. MCV of reference samples affects EMA test results; thus, we recommend selection of reference samples with MCV in range of ±2 fL compared to MCV of patient RBC’s.