Identification of a novel de novo ANK1 R1426* nonsense mutation in a Chinese family with hereditary spherocytosis by NGS

Identification of a novel ANK1 mutation in a Chinese family with hereditary spherocytosis: A case report

The present study describes the clinical profile and ankyrin 1 (ANK1) mutation status of a Chinese family with hereditary spherocytosis (HS). A young male patient (proband) was diagnosed with HS after presenting with anaemia and jaundice. The Coombs test was negative and spherocytes were found in peripheral blood smears. Magnetic resonance imaging showed splenomegaly and splenic iron depositions. The red blood cell osmotic fragility test was positive. The eosin-5'-maleimide binding test showed reduced mean channel fluorescence. Whole-exome sequencing revealed a novel ANK1 mutation (c.4707G>A), resulting in a nonsense mutation (p.Trp1569*). The patient's father, paternal aunt and paternal grandmother exhibited comparable clinical symptoms and Sanger sequencing confirmed the same mutation in these family members. To the best of our knowledge, an HS pedigree with this novel ANK1 nonsense mutation has not been previously reported. At the same time, the unique clinical presentation of this pedigree helps our understanding of the heterogeneity of clinical manifestations of HS.

Impact of Next-Generation Sequencing on the Diagnosis and Treatment of Congenital Anemias

Congenital anemias are a wide spectrum of diseases including hypoproliferative anemia syndromes, dyserythropoietic anemias, sideroblastic anemias, red blood cell membrane and enzymatic defects, hemoglobinopathies, and thalassemia syndromes. The various congenital anemia syndromes may have similar clinical and laboratory presentations, making the diagnosis challenging. The traditional work-up, which includes a complete blood count, blood smears, bone marrow studies, flow cytometry, and the osmotic fragility test, does not always lead to the diagnosis. Specialized tests such as red blood cell enzyme activity and ektacytometry are not widely available. In addition, red blood cell transfusions may mask some of the laboratory characteristics. Therefore, genetic testing is crucial for accurate diagnosis of patients with congenital anemias. However, gene-by-gene testing is labor intensive because of the large number of genes involved. Thus, targeted next-generation sequencing using custom-made gene panels has been increasingly utilized, with a high success rate of diagnosis. Accurate genetic diagnosis is important for determining specific therapeutic modalities, as well as for avoiding splenectomy when contraindicated. In addition, molecular diagnosis can allow for genetic counseling and prenatal diagnosis in severe cases. We suggest a work-up scheme for patients with congenital anemias, including early incorporation of targeted next-generation sequencing panels.

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.

Preliminary Study on the Clinical and Genetic Characteristics of Hereditary Spherocytosis in 15 Chinese Children

Objective

To investigate the clinical and genetic characteristics of hereditary spherocythemia (HS) in Chinese children, and to analyze the potential genotypic/phenotypic associations.

Methods

The clinical data and gene test results of children with HS were collected. All patients were diagnosed by gene test results, and the laboratory results were obtained before splenectomy. The data of red blood cell (RBC), hemoglobin (HB), mean red blood cell volume (MCV), mean red blood cell hemoglobin (MCH), mean red blood cell hemoglobin concentration (MCHC), and hematocrit (HCT) were statistically analyzed according to different mutation genes. Statistical methods for comparison between groups Mann–Whitney test analysis, two-terminal p < 0.05 was considered significant difference.

Results

A total of 15 children were enrolled in our hospital, and 14 variants were found (nine variants have not been reported before), including 10 ANK1 mutations (seven ANK1 truncated mutations) and five SPTB mutations. Patients with ANK1 mutations had more severe anemia than those with SPTB mutations (significantly lower RBC, HB, MCHC, and HCT).

Conclusion

This is one of the few studies on the genetic and clinical characteristics of children with HS in China. This study identified the unique genetic and clinical characteristics of Chinese children with HS and analyzed the pathogenic genotype–phenotypic association. The results confirmed that the anemia degree of HS patients caused by ANK1 was more serious than that of patients with SPTB deficiency. However, further study of the correlation between genotype and phenotype requires a larger sample size.

Identification of a De Novoc.1000delA ANK1 mutation associated to hereditary spherocytosis in a neonate with Coombs-negative hemolytic jaundice-case reports and review of the literature

Background

To strengthen the understanding of Hereditary Spherocytosis (HS) and determine the disease-causing mutation present with neonatal jaundice. HS is a hemolytic condition resulting from various erythrocyte membrane defects. Many different mutations result in HS, including mutations in ANK1.

Case presentation

A term neonate presented at ten hours with severe jaundice requiring exchange transfusion. At two months he was hospitalized due to repeated pallor and anemia requiring blood transfusions. Using next-generation sequencing, we discovered the responsible mutation in the proband but not in his parents; a heterozygous nucleotide variation of c.1000delA (p.1334Sfs*6) in ANK1. Thus hereditary spherocytosis was diagnosed.

Conclusions

Genetic detection is an important means of discovering the cause of hemolytic anemia in neonates and infants where routine diagnostic tests are unrevealing. We found a novel de novo mutation, c.1000delA (p.1334Sfs*6) in ANK1 that might account for other cases of HS in the Chinese population.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12920-021-00912-3.

[Clinical characteristics and genetic analysis of hereditary spherocytosis caused by mutations of ANK1 and SPTB genes]

This study analyzed the clinical features of 5 children with hereditary spherocytosis (HS) and the characteristics of ANK1 and SPTB gene mutations. All 5 children were confirmed with HS by peripheral blood genetic detection. Anemia, jaundice and splenomegaly were observed in all 5 children. Three children had an increase in erythrocyte osmotic fragility. All 5 children had negative results of the Coombs test, glucose 6 phosphate dehydrogenase test, sucrose hemolysis test, acidified-serum hemolysis test and thalassemia gene test. Peripheral blood smear showed an increase in spherocyte count in one child. High-throughput sequencing revealed ANK1 gene mutations in patients 1 to 3, namely c.3398(exon29)delA, c.4306C>T and c.957(exon9)_c.961(exon9)delAATCT, among which c.3398(exon29)delA had not been reported before. Patient 4 had c.318delGExon3 mutation in the SPTB gene. Patient 5 had mutations in the SPTB and SLC4A1 genes, among which c.3484delC in the SPTB gene was a spontaneous mutation; the mutation site of the SLCA4A1 gene was inherited from the father and was a non-pathogenic gene. This study suggests that anemia, jaundice and splenomegaly are major clinical manifestations of HS children. Most children with HS do not have the typical spherocytic changes. Genetic detection may help with the accurate diagnosis of HS.

A de novo ANK1 mutation associated to hereditary spherocytosis: a case report

Background

Hereditary spherocytosis (HS) is a type of hemolytic anemia caused by abnormal red cell membrane skeletal proteins with few unique clinical manifestations in the neonate and infant. An ANK1 gene mutation is the most common cause of HS.

Case presentation

The patient was a 11-month-old boy who suffered from anemia and needed a regular transfusion therapy at an interval of 2–3 months. Hematological investigations showed moderate anemia (Hb80 g/L). Red cells displayed microcytosis (MCV76.4 fl, MCH25.6 pg, MCHC335 g/L). The reticulocytes were elevated (4.8%) and the spherocytes were increased (10%). Direct antiglobulin test was negative. Biochemical test indicated a slight elevation of bilirubin, mainly indirect reacting (TBIL32.5 μmol/L, IBIL24 μmol/L). The neonatal HS ratio is 4.38, obviously up the threshold. Meanwhile, a de novo ANK1 mutation (exon 25:c.2693dupC:p.A899Sfs*11) was identified by next-generation sequencing (NGS). Thus, hereditary spherocytosis was finally diagnosed.

Conclusions

Gene detection should be considered in some hemolytic anemia which is difficult to diagnose by routine means. We identified a novel de novo ANK1 heterozygous frameshift mutation in a Yi nationality patient while neither of his parents carried this mutation.

Electronic supplementary material

The online version of this article (10.1186/s12887-019-1436-4) contains supplementary material, which is available to authorized users.

Novel compound heterozygous mutations in the SPTA1 gene, causing hereditary spherocytosis in a neonate with Coombs‑negative hemolytic jaundice

Hereditary spherocytosis (HS) is a common heterogeneous type of inherited hemolytic anemia characterized by jaundice and splenomegaly. Diagnosis of HS in neonates is considered unreliable, and is generally based on positive family history, spherocytes in peripheral smears, increased osmotic fragility, and jaundice. In the present study, routine laboratory tests, next‑generation sequencing, and Sanger sequencing were applied to diagnose a neonatal patient with Coombs‑negative hemolytic jaundice. The neonate had no family history of HS; however, spherocytes were observed in peripheral smears, and the patient exhibited Coombs‑negative and severe hemolytic jaundice, normal mean corpuscular hemoglobin concentration (MCHC) and mean corpuscular volume (MCV), normal glucose‑6‑phosphate dehydrogenase activity, negative thalassemia genetic mutation screening results, and negative autoimmune antibody tests. Novel compound heterozygous mutations in the spectrin‑α, erythrocytic 1 (SPTA1) gene (c.3897‑1G>C and c.5029G>A) were identified. The SPTA1 c.3897‑1G>C mutation in intron 27‑1, which disrupted the consensus splice site, was inherited from his asymptomatic mother, and the SPTA1 c.5029G>A (p.Gly1677Arg) mutation in trans with the SPTA1 c.3897‑1G>C mutation was inherited from his asymptomatic father. Sanger sequencing of mRNA reverse transcribed into cDNA identified a deletion of the first 10 nucleotides of exon 28, confirming the splicing mutation. In conclusion, the present study reports a rare case of autosomal‑recessive HS with a severe clinical phenotype, but normal MCHC and MCV.

Spectrum of Ankyrin Mutations in Hereditary Spherocytosis: A Case Report and Review of the Literature

BACKGROUND/AIMS

Hereditary spherocytosis (HS) is a common pediatric hemolytic anemia caused by congenital red blood cell defects. HS due to ankyrin 1 (ANK1) mutations is the most common type. We explored an ANK1 mutation from an HS patient and reviewed the literature.

METHODS

We detected the mutation in a Chinese family in which 2 members were diagnosed with HS by next-generation sequencing. The proband was diagnosed with HS in the newborn period, based on clinical manifestations, laboratory data, and family history. The mutation spectrum of the ANK1 gene was summarized based on 85 patients diagnosed with HS carrying ANK1 mutations, and the ANK1 mutation spectrum was summarized and analyzed.

RESULTS

We identified a novel mutation affecting ANK1 gene splicing (a splicing mutation) in both the patient and her mother, which is a substitution of T>G 2 nt after exon 25 in intron 26. The study expands our knowledge of the ANK1 gene mutation spectrum, providing a molecular basis for HS.

CONCLUSION

A novel ANK1 mutation (NM_000037.3, c.2960+2T>G, intron 26) that is potentially associated with HS was identified. To date, 80 ANK1 mutations have been reported to be associated with HS in humans.