Screening for ELANE, HAX1 and GFI1 gene mutations in children with neutropenia and clinical characterization of two novel mutations in ELANE gene.

BACKGROUND: Congenital neutropenia is a rare disease. Recurrent infections since young age are the presentation. The most common mutation causing severe congenital neutropenia (SCN) and cyclic neutropenia (CyN) is the ELANE gene. The objectives of this study were to screen the three common genetic mutations of ELANE, HAX1 and GFI1 in children with chronic neutropenia and to describe the clinical characteristics of children who had the mutations. METHODS: Infants having ANC < 1,000/cu mm or children aged > 1 year having ANC < 1,500/cu mm at least 3 times in 3 months were enrolled in the study. Patients who had acquired neutropenia due to infection, immune deficiency, or drugs were excluded. The ELANE gene was first studied; and if mutations were not identified, the HAX1 and GFI1 genes were further examined. RESULTS: A total of 60 patients were enrolled in the study. The median (range) age, ratio of female to male, ANC, and last follow-up age were 9.2 (0.5-45.2) months, 1:1.2, 248 (0-1,101) /cu mm, and 19.9 (3.5-202.3) months, respectively. Infections were noted in 67.3% of all patients. ELANE gene mutation was found in only four patients (6.7%), and the rest (56 patients) showed no mutations in the HAX1 and GFI1 genes. In patients without mutations, 66.0% had normal ANC during the follow-up, with a median (range) age for normal ANC of 19.8 (4.0-60.0) months. Two novel mutations p. Ala79del (c.234_236del) and p. Val197GlufsTer18 (c.589_590insAGGCCGGC) were identified, and they respectively cause SCN and CyN. Patients with the two novel mutations presented with several episodes of infection, including pneumonia, sepsis, abscess, otitis media, and gum infection. CONCLUSION: The genetic screening for ELANE, HAX1, and GFI1 gene mutations in 60 patients with chronic neutropenia could identify four patients (6.7%) with ELANE gene mutation and two novel mutations, p. Ala79del in exon 3 and p. Val197GlufsTer18 in exon 4 causing SCN; and CyN, respectively.

Congenital neutropenia: From lab bench to clinic bedside and back.

Neutropenia is a hematological condition characterized by a decrease in absolute neutrophil count (ANC) in peripheral blood, typically classified in adults as mild (1-1.5 × 109/L), moderate (0.5-1 × 109/L), or severe (< 0.5 × 109/L). It can be categorized into two types: congenital and acquired. Congenital severe chronic neutropenia (SCN) arises from mutations in various genes, with different inheritance patterns, including autosomal recessive, autosomal dominant, and X-linked forms, often linked to mitochondrial diseases. The most common genetic cause is alterations in the ELANE gene. Some cases exist as non-syndromic neutropenia within the SCN spectrum, where genetic origins remain unidentified. The clinical consequences of congenital neutropenia depend on granulocyte levels and dysfunction. Infants with this condition often experience recurrent bacterial infections, with approximately half facing severe infections within their first six months of life. These infections commonly affect the respiratory system, digestive tract, and skin, resulting in symptoms like fever, abscesses, and even sepsis. The severity of these symptoms varies, and the specific organs and systems affected depend on the genetic defect. Congenital neutropenia elevates the risk of developing acute myeloid leukemia (AML) or myelodysplastic syndromes (MDS), particularly with certain genetic variants. SCN patients may acquire CSF3R and RUNX1 mutations, which can predict the development of leukemia. It is important to note that high-dose granulocyte colony-stimulating factor (G-CSF) treatment may have the potential to promote leukemogenesis. Treatment for neutropenia involves antibiotics, drugs that boost neutrophil production, or bone marrow transplants. Immediate treatment is essential due to the heightened risk of severe infections. In severe congenital or cyclic neutropenia (CyN), the primary therapy is G-CSF, often combined with antibiotics. The G-CSF dosage is gradually increased to normalize neutrophil counts. Hematopoietic stem cell transplants are considered for non-responders or those at risk of AML/MDS. In cases of WHIM syndrome, CXCR4 inhibitors can be effective. Future treatments may involve gene editing and the use of the diabetes drug empagliflozin to alleviate neutropenia symptoms.

Case Report: Characterization of known (c.607G>C) and novel (c.416C>G) ELANE mutations in two Mexican families with congenital neutropenia.

The most common causes of congenital neutropenia are mutations in the ELANE (Elastase, Neutrophil Expressed) gene (19p13.3), mostly in exon 5 and the distal portion of exon 4, which result in different clinical phenotypes of neutropenia. Here, we report two pathogenic mutations in ELANE, namely, c.607G>C (p.Gly203Arg) and a novel variant c.416C>G (p.Pro139Arg), found in two Mexican families ascertained via patients with congenital neutropenia who responded positively to the granulocyte colony-stimulating factor (G-CSF) treatment. These findings highlight the usefulness of identifying variants in patients with inborn errors of immunity for early clinical management and the need to rule out mosaicism in noncarrier parents with more than one case in the family.

Cyclic Neutropenia Mimicking Crohn's Disease: Two Case Reports and a Narrative Review.

Cyclic neutropenia is a rare hematological condition characterized by periodic fluctuations in neutrophil counts, with a 21-day periodicity. Clinical presentation varies from mild to severe forms of the disease, with the onset of recurrent fever, painful oral ulcers, recurrent bacterial infections, peritonitis, and septic shock. The availability of granulocyte colony-stimulating factor (G-CSF) has revolutionized the management and natural history of this disease, regulating the proliferation, differentiation, and maturation of the progenitor cells, and reducing the duration of neutropenia. Inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), is a group of chronic pathologies that affect the gastrointestinal tract. The onset of both diseases may be at a young age (even during childhood or adolescence), and clinical manifestations may lead to misdiagnosis, due to similar characteristics such as recurrent infections, oral ulcers, perianal abscesses, and infertility. Moreover, the two pathologies are rarely associated, with different management and therapeutic options. Here, we describe two case reports of patients who underwent surgery because of diagnosis of complicated CD. After surgery, due to persistent neutropenia, the hematologist consultant confirmed suspicions of cyclic neutropenia, and G-CSF therapy was started with benefits, underlining the crucial importance of proper differential diagnosis.

A distinct case of an 8-year-old female with cyclic neutropenia presenting with C. septicum abdominal sepsis and myonecrosis requiring a bowel resection and leg fasciotomy.

Clostridium septicum is a very rare cause of severe spontaneous pediatric enterocolitis and is often associated with underlying malignancy or immunocompromise. Likewise, cyclic neutropenia is a rare congenital immunodeficiency that is characterized by cyclical periods of neutropenia, often with more severe symptoms in the pediatric population. Here, we present a unique case of spontaneous C. septicum enterocolitis, sepsis, and myonecrosis in a child with undiagnosed cyclic neutropenia. Early recognition of pediatric sepsis, frequent reevaluation and identification of rapidly progressive infection, and early surgical intervention are critical for the effective management of a rare and severe infection.

Cyclic neutropenia and concomitant IgA nephropathy: a case report.

BACKGROUND: IgA nephropathy (IgAN) is universally recognized as one of the most common primary glomerular diseases in all ages. Cyclic neutropenia (CN) is a rare haematologic disorder that is associated with mutations of the ELANE gene. The co-occurrence of IgAN and CN is extremely rare. This is the first case report of a patient with IgAN and genetically confirmed CN. CASE PRESENTATION: We report a case of a 10-year-old boy who presented with recurrent viral upper respiratory tract infections accompanied by several episodes of febrile neutropenia, haematuria, proteinuria and acute kidney injury. Upon first admission, his physical examination was unremarkable. His kidney function was impaired, whereas his urine microscopy showed evidence of macroscopic haematuria and proteinuria. Further workup showed elevated IgA. The renal histology was consistent with mesangial and endocapillary hypercellularity with mild crescentic lesions, while immunofluorescence microscopy showed IgA-positive staining, which was characteristic of IgAN. Moreover, genetic testing confirmed the clinical diagnosis of CN, therefore Granulocyte colony-stimulating factor (G-CSF) was initiated to stabilize the neutrophil count. Regarding proteinuria control, the patient was initially treated with an Angiotensin-converting-enzyme inhibitor for approximately 28 months. However, due to progressive proteinuria (> 1 g/24 h), Corticosteroids (CS) were added for a period of 6 months according to the revised 2021 KDIGO guidelines with favorable outcome. CONCLUSIONS: Patients with CN are more susceptible to recurrent viral infections, which can trigger IgAN attacks. In our case CS induced remarkable proteinuria remission. The use of G-CSF contributed to the resolution of severe neutropenic episodes, viral infections and concomitant AKI episodes, contributing to better prognosis of IgAN. Further studies are mandatory to determine whether there is a genetical predisposition for IgAN in children with CN.

Case report: Five-year periodontal management of a patient with two novel mutation sites in ELANE-induced cyclic neutropenia.

Cyclic neutropenia (CyN) is a rare, ELANE-related neutropenia. Oral manifestations are among the initial signs of CyN and an important reason that leads patients to seek professional help. This case report describes a 12-year-old girl with recurrent oral ulcers, severe chronic periodontitis, and pathological tooth migration as the initial and main clinical symptoms of CyN. Two novel mutations in ELANE, c.180T>G (p.I60M) and c.182C>G (p.A61G) associated with CyN were observed. Bioinformatics research indicated lower stability and impaired molecular linkages of the mutant neutrophil elastase (NE) encoded by ELANE. However, the enzyme affinity to the classic substrate Suc-Ala-Ala-Ala-pNA was not substantially changed, suggesting that the impaired integrity and stability of the mutant NE, rather than catalytic deficiency, might be the pathogenic mechanism of ELANE mutation-induced neutropenia. The patient was prescribed scaling and root planing (SRP) and monthly periodontal maintenance without systemic management. Although the routine periodontal treatment was occasionally interrupted by the 2019 coronavirus pandemic, her periodontal devastation remained well-remitted in the 5-year follow-up assessment. The results of this study confirmed the importance of plaque control and proper diagnosis in the periodontal management of such patients and provide better clinical references. In addition, the novel mutations identified in this study expand the spectrum of known ELANE mutations in CyN and further contribute to knowledge regarding its pathogenic mechanism.

Case Report: Association between cyclic neutropenia and SRP54 deficiency.

Autosomal dominant mutations in the signal recognition particle (SRP) 54 gene were recently described in patients with severe congenital neutropenia (SCN). SRP54 deficiency cause a chronic and profound neutropenia with maturation arrest at the promyelocyte stage, occurring in the first months of life. Nearly all reported patients with SRP54 mutations had neutropenia without a cyclic pattern and showed a poor or no response to granulocyte colony-stimulating factor (G-CSF) therapy. We report here an 11-year-old female patient with cyclic neutropenia and recurrent heterozygous p.T117del (c.349_351del) in-frame deletion mutation in SRP54, who showed remarkable therapeutic response to G-CSF treatment. The diagnosis of cyclic pattern of neutropenia was established by acceptable standards. ELANE gene mutation was excluded by using various genetic approaches. The patient described here also had dolichocolon which has not been described before in association with SCN.

Assessment of Congenital Neutropenia in Children: Common Clinical Sceneries and Clues for Management.

A disparate group of rare hematological diseases characterized by impaired maturation of neutrophil granulocytes defines congenital neutropenias. Neutropenic patients are prone to recurrent infections beginning in the first months of life. Of interest is "cyclic neutropenia," an ultra-rare disorder revealed by sinusoidal variations in the neutrophil count and recurring infections every 21 days. Diagnosis of these disorders is frequently obscured by the multiple causes of recurrent fevers in children. The aim of this overview is to outline the physical assessment of children presenting with early-onset symptomatic neutropenia, identify the disease between the many medical conditions and even emergencies which should enter in differential diagnosis, hint at the potential management with granulocyte-colony stimulating factor, define the risk of evolution to hematologic malignancy, and summarize inter-professional team strategies for improving care coordination and outcomes of patients.

Neutrophil Elastase Defects in Congenital Neutropenia.

Severe congenital neutropenia (SCN) is a rare hematological condition with heterogenous genetic background. Neutrophil elastase (NE) encoded by ELANE gene is mutated in over half of the SCN cases. The role of NE defects in myelocytes maturation arrest in bone marrow is widely investigated; however, the mechanism underlying this phenomenon has still remained unclear. In this review, we sum up the studies exploring mechanisms of neutrophil deficiency, biological role of NE in neutrophil and the effects of ELANE mutation and neutropenia pathogenesis. We also explain the hypotheses presented so far and summarize options of neutropenia therapy.

Management of acute cholecystitis in patient with cyclic neutropenia: a case report.

BACKGROUND: Cyclic neutropenia is a disease that causes a neutropenic decrease in peripheral blood in a cycle of about 21 days. It is a rare hereditary disorder with an estimated incidence of 0.5-1 cases per million population. The absolute neutrophil count can drop to zero, and neutropenic nadir may last for 3-5 days. This is a rare disease, and there are few reports of abdominal surgery in cyclic neutropenia patients; thus, we report this case of neutrophil count fluctuation and perioperative management. CASE PRESENTATION: A 31-year-old man with cyclic neutropenia was transferred to our hospital complaining of right season rib pain, but no rebound tenderness. His C-reactive protein was elevated (4.37 mg/L) and computed tomography revealed a large number of small stones in the gallbladder body and an incarceration in the gallbladder neck. He was diagnosed with acute cholecystitis. Ideally, surgical intervention should have been performed immediately, but because his neutrophil count was 300/µL, endoscopic naso-gallbladder drainage was performed and he was provided antibiotics until his neutrophil count increased to acceptable levels. Three days after admission, his neutrophil count had increased and laparoscopic cholecystectomy was performed. For one week after the operation, antibiotics were administered; he had an uneventful postoperative recovery. He was discharged on the seventh postoperative day and provided an oral antibiotic. CONCLUSIONS: Infection can be serious in patients with cyclic neutropenia, and it is therefore, important to determine the timing of surgery and to apply appropriate perioperative management with drainage and antibiotic administration.

New insights into the pathomechanism of cyclic neutropenia.

Cyclic neutropenia (CyN) is a hematologic disorder in which peripheral blood absolute neutrophil counts (ANCs) show cycles of approximately 21-day intervals. The majority of CyN patients harbor ELANE mutations, but the mechanism of ANC cycling is unclear. We performed analysis of bone marrow (BM) subpopulations in CyN patients at the peak and the nadir of the ANC cycle and detected high proportions of BM hematopoietic stem cells (HSCs) and hematopoietic stem and progenitor cells (HSPCs) at the nadir of the ANC cycle, as compared with the peak. BM HSPCs produced fewer granulocyte colony-forming unit colonies at the ANC peak. To investigate the mechanism of cycling, we found that mRNA expression levels of ELANE and unfolded protein response (UPR)-related genes (ATF6, BiP (HSPA5), CHOP (DDIT3), and PERK (EIF2AK3)) were elevated, but antiapoptotic genes (Bcl-2 (BCL2) and bcl-xL (BCL2L1)) were reduced in CD34+ cells tested at the ANC nadir. Moreover, HSPCs revealed increased levels of reactive oxygen species and gH2AX at the ANC nadir. We suggest that in CyN patients, some HSPCs escape the UPR-induced endoplasmic reticulum (ER) stress and proliferate in response to granulocyte colony-stimulating factor (G-CSF) to a certain threshold at which UPR again affects the majority of HSPCs. There is a cyclic balance between ER stress-induced apoptosis of HSPCs and compensatory G-CSF-stimulated HSPC proliferation followed by granulocytic differentiation.

Recurrent Periorbital Cellulitis Secondary to Cyclic Neutropenia.

PURPOSE: To present a 1-year-old boy with cyclic neutropenia who presented with multiple episodes of periorbital cellulitis (POC). METHODS: The child presented with three episodes of POC. In the second episode, the cellulitis was associated with nasolacrimal duct obstruction, and in the third episode, a pansinusitis was noted. He underwent a thorough systemic evaluation. RESULTS: Patient's evaluation revealed the diagnosis of cyclic neutropenia. CONCLUSION: This report emphasizes the possibility of an underlying immunodeficiency with recurrent POC, even in an apparently healthy child.

Cyclic thrombocytopenia with statistically significant neutrophil oscillations.

Cyclic thrombocytopenia is often misdiagnosed as immune thrombocytopenia due to similar clinical features, a fact of significance because cyclic thrombocytopenia generally responds poorly to treatments used successfully in immune thrombocytopenia. A precise diagnosis must establish the statistical significance of periodicity of the platelet counts using statistical methods (eg, Lomb-Scargle periodogram).

Elastase inhibitors as potential therapies for ELANE-associated neutropenia.

Mutations in ELANE, the gene for neutrophil elastase (NE), a protease expressed early in neutrophil development, are the most frequent cause of cyclic (CyN) and severe congenital neutropenia (SCN). We hypothesized that inhibitors of NE, acting either by directly inhibiting enzymatic activity or as chaperones for the mutant protein, might be effective as therapy for CyN and SCN. We investigated ß-lactam-based inhibitors of human NE (Merck Research Laboratories, Kenilworth, NJ, USA), focusing on 1 inhibitor called MK0339, a potent, orally absorbed agent that had been tested in clinical trials and shown to have a favorable safety profile. Because fresh, primary bone marrow cells are rarely available in sufficient quantities for research studies, we used 3 cellular models: patient-derived, induced pluripotent stem cells (iPSCs); HL60 cells transiently expressing mutant NE; and HL60 cells with regulated expression of the mutant enzyme. In all 3 models, the cells expressing the mutant enzyme had reduced survival as measured with annexin V and FACS. Coincubation with the inhibitors, particularly MK0339, promoted cell survival and increased formation of mature neutrophils. These studies suggest that cell-permeable inhibitors of neutrophil elastase show promise as novel therapies for ELANE-associated neutropenia.

Progress in diagnosis and treatment of cyclic neutropenia / 国际儿科学杂志

Cyclic neutropenia (CN) is a kind of hereditary disease with periodic onset of neutrophil reduction and recurrent infection,which can be sporadic or familial.CN was firstly reported in 1910,and it was not until 1999 that the cause of the CN was further identified by investigators.Because the incidence of CN is low,the disease is rarely reported in China.CN is caused by mutations in the gene for neutrophil elastase (ELA-2 or ELANE),and it is a rare,inherited autosomal dominant disorder.Diagnosis of CN is based on the medical history and blood cycle characteristics.With the continuous development of medical technology,gene testing has certain significance for the diagnosis of CN.For the treatment,the most important is infection prevention,symptomatic treatment,the use of granulocyte colony-stimulating factor,and so forth.Although CN is a hematological disease,most cases have good prognosis,and will not result in malignant hematological diseases such as leukemia.At present,the doctors' awareness of CN has been lacking,which leads to misdiagnosis.The symptom and sign are not specific at the onset of CN,thus there is often misdiagnosis.In order to deepen the understanding of this disease and improve the skills of diagnosis and treatment,this review summarizes the pathogenesis,clinical manifestation,clinical characteristics,diagnosis and treatment of CN.

Neutropenia cíclica. Reporte de un caso / Cyclic neutropenia. Clinical case report

La neutropenia cíclica ocurre debido a que los niveles de producción celular por parte de las células madre de la médula ósea fluctúan, es decir, cambian durante el ciclo; aunque el número es recurrentemente bajo, su función es normal. Fue descrita por primera vez por Leale en 1910, con carácter autosómico dominante. Se presenta aproximadamente cada 21 días con un rango de 14 a 36 días durando un total de 3 a 6. Durante el periodo en el que existen pocos neutrófilos circulantes, el paciente es susceptible a las infecciones. Dentro del cuadro clínico se presentan: susceptibilidad a infecciones, cuadros febriles, fatiga, úlceras orales, impétigo, aumento de ganglios linfáticos, periodontitis, estomatitis. Es importante manejar estomatológicamente a estos pacientes, previa interconsulta con médico tratante, prevenir cuadros infecciosos bajo un esquema profiláctico a base de amoxicilina 50 mg/kg peso o clindamicina 20 mg/kg peso, revisar biometría hemática reciente (máximo 10 días previos al tratamiento); en tratamientos de urgencia se manejará de forma conservadora el dolor e infección; uso de enjuagues con clorhexidina al 0.12% y solución Philadelphia en caso de ser necesario.

Cyclic neutropenia occurs due to the fluctuation of cellular production levels of bone marrow stem cells. This is to say, they change during the cycle, and although numbers are recurrently low, function is normal. Cyclic neutropenia was first described by Leale in 1910 with dominant autosomal character. It manifests approximately every 21 days, with range of 14 to 36 days, lasting 3-6 days per episode. During the time when there are few circulating neutrophils, the patient is susceptible to infections. The clinical picture of this process includes: susceptibility to infection, feverish conditions, oral ulcers, impetigo, increased lymph nodes, periodontitis and stomatitis. It is important to stomatologically handle these patients; after inter-consultation with treating physician, prevent infection in a prophylactic scheme based on amoxicillin 50 mg/per kg weight or clindamycin 20 mg/per kg weight, review recent blood count results (maximum ten days before treatment). In emergency treatments pain and infection will be handled conservatively, with use of 0.12% chlorhexidine mouthwashes and Philadelphia solution when necessary.

Appendectomy in a child with cyclic neutropenia in profound neutropenic episode.

Our experience in the treatment of a 4-year-old boy with cyclic neutropenia who was admitted for urgent appendectomy is described. The postoperative course was uneventful with high daily doses of granulocyte colony-stimulating factor and antimicrobial therapy. The purpose of this report is to highlight the importance of immediate appendectomy in neutropenic patients, wherein low absolute neutrophil count should not be considered as a contraindication for urgent surgical procedure.

Hematogones in the peripheral blood of a 5½-month-old boy with cyclic neutropenia due to heterozygous, novel ELANE gene mutation p.Q97P, c.290 A>C.

We have identified a novel point mutation in the ELANE gene of a 5.5-month-old boy with severe cyclic neutropenia, and we are reporting for the first time, to our knowledge, the presence of hematogones in the peripheral blood of an infant. The novel point mutation occurred at base number 290 in codon 97, where adenine was replaced with cytosine. The mutation caused the replacement of amino acid glutamine with amino acid proline in the activation domain of the elastase 2 enzyme. The heterozygous mutation generated severe cyclic neutropenia, granulocytic maturation arrest, an increased number of hematogones (26% of marrow cells) in the bone marrow, an absence of neutrophils, and the presence of stage 3 (mature) hematogones in the peripheral blood. The percentage of hematogones in the peripheral blood was inversely proportional to the absolute number of neutrophils. Leukemic number of blast-like cells (hematogones) in the bone marrow, blast-like cells in the peripheral blood, marked neutropenia, and the arrest of granulopoiesis might suggest an acute leukemia. However, the finding of characteristic flow cytometric features of hematogones should help to avoid a wrong diagnosis.