Correction of the pathogenic mutation in the G6PC3 gene by adenine base editing in mutant embryos / 中华血液学杂志

Objective: To determine whether the adenine base editor (ABE7.10) can be used to fix harmful mutations in the human G6PC3 gene. Methods: To investigate the safety of base-edited embryos, off-target analysis by deep sequencing was used to examine the feasibility and editing efficiency of various sgRNA expression vectors. The human HEK293T mutation models and human embryos were also used to test the feasibility and editing efficiency of correction. Results: ①The G6PC3(C295T) mutant cell model was successfully created. ②In the G6PC3(C295T) mutant cell model, three distinct Re-sgRNAs were created and corrected, with base correction efficiency ranging from 8.79% to 19.56% . ③ ABE7.10 could successfully fix mutant bases in the human pathogenic embryo test; however, base editing events had also happened in other locations. ④ With the exception of one noncoding site, which had a high safety rate, deep sequencing analysis revealed that the detection of 32 probable off-target sites was <0.5% . Conclusion: This study proposes a new base correction strategy based on human pathogenic embryos; however, it also produces a certain nontarget site editing, which needs to be further analyzed on the PAM site or editor window.

Severe Congenital Neutropenia Type 4: A Rare Disease Harboring a G6pc3 Gene Pathogenic Variant Particular to the Mexican Population

ABSTRACT Background: Severe congenital neutropenia type 4 (SCN4) is a rare autosomal recessive granulopoiesis disorder caused by G6PC3 gene pathogenic variants. The estimated prevalence is 1/10,000,000 people. Over 90% of patients present a syndromic form with variable multisystemic involvement, including congenital heart defects, increased visibility of superficial veins (IVSV), inflammatory bowel disease, and congenital urogenital defects as prominent symptoms. Objectives: The objective of the study was to study non-hematological phenotypic findings that suggest a clinical diagnosis of SCN4. Methods: We examined medical records of patients diagnosed with neutropenia from January 2000 to December 2020, selecting cases with non-hematologic manifestations for phenotypic description and G6PC3 gene sequencing. Results: We found 11 cases with non-hematologic features: congenital heart defects in 8, IVSV in 6, inflammatory bowel disease in 4, urogenital defects in 4, and similar facial appearance. In addition, Sanger sequencing confirmed 3 homozygous cases for the c.210delC variant, a compound heterozygous harboring this variant, and a c.199_218+1 deletion. Conclusions: Our findings of the c.210delC variant in very close geographical settings, to date, have only been reported among Mexicans, and a mutual uncommon surname in two families strongly supports a founder effect for the variant in the studied population. Furthermore, the described non-hematologic symptoms in patients with severe primary neutropenia should be explored, confirming SCN4 by investigating G6PC3 gene mutations.

Mutations of the ELANE gene cause severe congenital neutropenia with periodontal disease: a case report / 华西口腔医学杂志

Severe congenital neutropenia is a rare disorder characterized by a consistently low absolute neutrophil count and periodontal disease. This report describes the case of an ELANE mutationin a patient with gingival bleeding and tooth mobility. Oral examination showed active periodontal infection of the primary dentition accompanied by alveolar bone loss in the posterior region. The patient was diagnosed with severe congenital neutropenia 1 year after multidisciplinary consultation. Treatment of the systemic disease and effective oral health education over a 3-year follow-up period relieved the periodontal infection and created favorable conditions for future repair.

Congenital defects of phagocyte number or function / 中华实用儿科临床杂志

Congenital defects of phagocyte number,function or both was categorized to the fifth classification from the international union of immunological societies expert committee for primary immunodeficiency 2015.Severe congenital neutropenia was the most fatal phagocyte number defect.Phagocyte functions included motility,chemotaxis,adhesion,phagocytosis and killing.Leukocyte adhesion deficiency and chronic granulomatous disease were the most common diseases.This article will describe pathogenesis,molecular,clinical,laboratory features and treatment and prognosis,to supporting clues for paediatrician's clinical operations.

Current insights into inherited bone marrow failure syndromes / 소아과

Inherited bone marrow failure syndrome (IBMFS) encompasses a heterogeneous and complex group of genetic disorders characterized by physical malformations, insufficient blood cell production, and increased risk of malignancies. They often have substantial phenotype overlap, and therefore, genotyping is often a critical means of establishing a diagnosis. Current advances in the field of IBMFSs have identified multiple genes associated with IBMFSs and their pathways: genes involved in ribosome biogenesis, such as those associated with Diamond-Blackfan anemia and Shwachman-Diamond syndrome; genes involved in telomere maintenance, such as dyskeratosis congenita genes; genes encoding neutrophil elastase or neutrophil adhesion and mobility associated with severe congenital neutropenia; and genes involved in DNA recombination repair, such as those associated with Fanconi anemia. Early and adequate genetic diagnosis is required for proper management and follow-up in clinical practice. Recent advances using new molecular technologies, including next generation sequencing (NGS), have helped identify new candidate genes associated with the development of bone marrow failure. Targeted NGS using panels of large numbers of genes is rapidly gaining potential for use as a cost-effective diagnostic tool for the identification of mutations in newly diagnosed patients. In this review, we have described recent insights into IBMFS and how they are advancing our understanding of the disease's pathophysiology; we have also discussed the possible implications they will have in clinical practice for Korean patients.

Different Clinical Phenotypes in Familial Severe Congenital Neutropenia Cases with Same Mutation of the ELANE Gene

Severe congenital neutropenia (SCN) is a heterogeneous group of disorders with a defect in granulopoiesis causing marked neutropenia and severe bacterial infections. A 17-month-old girl (patient 1) was admitted due to cervical lymphadenitis caused by methicillin-resistant Staphylococcus aureus, with neutropenia. She had Pseudomonas aeruginosa sepsis and peritonitis with perforated appendicitis at 8-month of age. Her sister, a 37-month-old girl (patient 2), had recurrent stomatitis with profound neutropenia, and her mother, a 32-yr-old woman (patient 3), had had recurrent stomatitis until her early 20s with neutropenia. We found an ELANE gene mutation (c.597+1G > A) from them in direct DNA sequencing analysis. Patients 1 and 2 did not respond to granulocyte colony stimulating factor and patient 1 was treated with prolonged antibiotics and excision. We demonstrated inherited SCN cases showing different severity even with the same mutation of the ELANE gene in a family.

Report of a case of severe congenital neutropenia with literature review / 临床儿科杂志

Objective To investigate the clinical features and pathogenesis of severe congenital neutropenia (SCN) by detecting the gene mutation of a SCN patient suspected by clinical diagnosis. Methods The intravenous anticoagulant and clin-ical data and laboratory results of this child were collected;the phagocyte and oxidation function of neutrophils were evaluated by flow cytometry;ELANE, HAX1, WAS, GFI1, CSF3R and CXCR4 genes were screened by PCR amplification and sequencing. Results The neutrophil function of this patient was normal; sequencing results revealed no mutation occurred in ELANE, HAX1, WAS, GFI1, CSF3R and CXCR4;and granulocyte colony-stimulating factor (G-CSF) can obviously enhance the level of neutrophils. Conclusion SCN is a kind of genetic heterogeneity syndrome associated with multiple gene mutations, gene diag-nosis will contribute to understanding of the pathogenesis of the disease and provide theoretical basis for treatment. Though more and more pathogenic genes were found to be connected with SCN, the cases of unknown mutation still account for a large proportion of this disease.

Novel ELANE Gene Mutation in a Korean Girl with Severe Congenital Neutropenia

Severe congenital neutropenia is a heterozygous group of bone marrow failure syndromes that cause lifelong infections. Mutation of the ELANE gene encoding human neutrophil elastase is the most common genetic alteration. A Korean female pediatric patient was admitted because of recurrent cervical lymphadenitis without abscess formation. She had a past history of omphalitis and isolated neutropenia at birth. The peripheral blood showed a markedly decreased absolute neutrophil count, and the bone marrow findings revealed maturation arrest of myeloid precursors at the promyelocyte to myelocyte stage. Her direct DNA sequencing analysis demonstrated an ELANE gene mutation (c.607G > C; p.Gly203Arg), but her parents were negative for it. She showed only transient response after subcutaneous 15 microg/kg/day of granulocyte colony stimulating factor administration for six consecutive days. During the follow-up observation period, she suffered from subsequent seven febrile illnesses including urinary tract infection, septicemia, and cellulitis.

Molecular Analysis of Two Cases of Severe Congenital Neutropenia / 대한진단검사의학회지

Severe congenital neutropenia is a rare hematological disease characterized by a selective decrease in circulating neutrophils, maturation arrest of granulocytic precursors at the promyelocyte stage, and recurrence of infections. A 2-month-old male infant (patient A) and a 14-month-old female child (patient B) were referred to our hospital due to severe neutropenia. Sequencing analysis of ELA2 and HAX1 genes was performed. Two single nucleotide polymorphisms of HAX1 gene were found. They were 5,104T-->G point mutation of exon 1 and 5,474A-->G point mutation of intron 1 in HAX1 gene. The mutation of ELA2 gene was not found. The patient A showed a good response to granulocyte colony-stimulating factor (G-CSF) treatment and the absolute neutrophil count recovered to 1,195/microliter. But the patient B showed a partial response to G-CSF treatment and experienced several episodes of herpetic gingivostomatitis, oral ulcer, acute pharyngotonsillitis and otitis media during follow-up.