Congenital Neutropenia Research Articles

Fertility and Pregnancy in Patients with Congenital Neutropenia: Experience of the French Severe Chronic Neutropenia Registry in 565 Patients Above Age of 15 Years

CONCLUSION Congenital neutropenia (CN) are characterized by chronic neutropenia with frequent co-morbidities. Approximately 30 different entities have been described with various clinical phenotypes and genotypes (PMID: 28875503). As survival rates and life expectancy improve, fertility and pregnancies becomes a common issue. Only one study had addressed this question, reporting 38 pregnancies in women with idiopathic neutropenia (n=6) or CN (n=16) (PMID: 24997149 ). As of the last update at the end of June 2023, the French SCN registry enrolled 988 patients with a CN diagnosis, including 565 patients (282 males, 283 females) aged > 15 years old. The cumulative duration between 15 and 50 years of age for the total cohort is 8043 person-years, which can be considered as the years of potential fertility. For this study, we recorded the number of offspring, pregnancy outcomes, use of Granulocyte Colony Stimulating Factor (GCSF) during pregnancy, newborn outcomes and complications during pregnancy. Total fertility rate was calculated according to standard methodology (http://www.csss.washington.edu/Papers/wp97.pdf) RESULTS Among the 565 patients who may potentially be fertile, 109 patients (77 female among 283; 32 male among 282) became parents and a total of 211 offspring were recorded (table 1). In addition, medical termination of 5 pregnancies was performed in 5 patients with dominant CN disorders (ELANE and GATA2) following prenatal diagnosis. Globally, the total fertility rate in women was 3.4%, higher than the 2.1% rate in the general population in France. The fertility rate was heterogeneous, as some rare forms of CN may suffer from sterility (e.g. USB1 or CLPB heterozygous), or low fertility (e.g. SBDS, G6PC3 or GSDIb) whereas quite normal fertility was observed in others such as ELANE or GATA2. The parents' median age at first birth was 27 years (min, max: 18, 41 years). Among the 77 females who became pregnant, 39 received GCSF prior to the first conception; 14/32 males had received GCSF. No GCSF was initiated during pregnancy. GCSF was maintained on various schedules during the pregnancy in 24 pregnancies. Among the 24 babies born after receiving GCSF in utero, no malformations were observed. As expected, some offspring (n=54) were shown to have the the same genetic defect as their affected parent, in agreement with the autosomal dominant inheritance, mainly ELANE-CN or GATA2. Noteworthy, two post-HSCT (indicated for MDS) pregnancies were underwent in ELANE-CN whereas one mother has received chemotherapy for a solid tumour before pregnancy. We observed one severe intrapartum complication (eclampsia) in a woman with USB1-CN. Among the 211 births, prematurity (< 37 weeks) was present in 13 cases, IUGR (mean weight 2141 g and mean height 42 cm) in 15 cases, and macrosomia in 11 cases (mean weight 3774 g). Two early deaths due to prematurity and enterocolitis and 1 cerebral anoxo ischemia from a twin pregnancy were observed. In France, two-third of the patients with congenital neutropenia are adult. The total fertility rate in this population appears to be similar to the general population; although fertility is reduced in some subtypes of CN. No teratogenic effect of GCSF has been observed, but numbers are rather small.

A Universal CRISPR/Cas9n-Mediated Genome Editing Approach for ELANE-Related Severe Congenital Neutropenia

Severe congenital neutropenia (CN) is an inherited bone marrow failure syndrome characterized by impaired maturation of neutrophil granulocytes. Due to the lack or very low levels of neutrophils in the peripheral blood, patients experience severe, life-threatening bacterial infections as early as birth. Autosomal-dominant ELANE mutations are the most common cause of CN. Although most patients respond to daily treatment with recombinant human granulocyte colony-stimulating factor, about 15% of patients do not respond to this cytokine, and approximately 20% of patients develop myelodysplasia or acute myeloid leukemia. The only curative treatment available thus far is allogenic hematopoietic stem cell transplantation, which is associated with serious side effects. Autologous transplantation of gene-edited patients' HSPCs offers a novel curative therapy. Considering the wide range of mutations distributed throughout the ELANE gene, A universal, high-safety-profile approach could be advantageous for all ELANE-CN patients. Our group has already published a universal CRISPR/Cas9-mediated knockout approach for the ELANE gene; however, targeting the coding sequence region (CDS) of the ELANE gene could lead to the introduction of new disease-causing variants, so it may be harmful for patients. In order to address this concern, we reformatted our previously published knockout concept into a clinical-grade gene therapy strategy. We have screened cis-regulatory regions in the ELANE core promoter and, using CRISPR/Cas9n, introduced two nicks on opposing strands of the Goldberg-Hognes box region (TATA-box) to make the transcription starting process inefficient, as transcription factors and RNApol II cannot recognize the modified sequence. Theproposed strategy targets the non-coding region of the ELANE gene and thus does not generate new unwanted variants. Also, by replacing Cas9 with Cas9-ncikase, the off-target activity should decrease by up to 1000-fold. We have observed a markedly elevated neutrophil differentiation in gene-edited ELANE-CN patients HSPCs (n = 2), as assessed by the percentage of CD45 +CD11b +CD15 +, CD45 +CD15 +CD16 +, and CD45 +CD16 +CD66b + myeloid/granulocytic cells, compared to the mock electroporated ELANE-CN group, while no disruption of granulopoiesis in healthy donor HSPCs (n = 2) was detected. Results validated by the CFU assay. To have nucleotide-level resolution of on-target events, we performed targeted next-generation sequencing of edited loci on gene-edited healthy donors and ELANE-CN HSPCs. Next-generation sequencing results showed >90% on-target efficiency. CRISPR/Cas9n-mediated targeting of the TATA box rescued defective granulopoiesis in vivo, as gene-edited ELANE-CN HSPCs (n = 3) were transplanted in NSG mice and assessed by the percentage of neutrophils (hCD19 -hCD3 -hCD66b Int/lowhCD33 +hCD16 high) after 16 weeks. We have also observed efficient engraftment and preserved the multilineage potential of gene edited HSPCs in immunodeficient NSG mice. The strategy also depicted a safe profile upon applying gene editing to healthy donor CD34 + HSPCs and performing GUIDE-seq and CAST-seq. GUIDE-seq highlighted two potential off-target sites after >=6 mismatches, while no chromosomal translocations were detected by CAST-seq. RNA-sequencing of in vitro-generated neutrophils from gene-edited HSPCs of healthy donors (n = 2) confirmed a >9-fold reduction of ELANE gene expression level. Important to note, none of the other serine proteases or neighboring genes were down-regulated. Taken together, ex vivo CRISPR-Cas9n-based gene editing of ELANE's gene promoter in the setting of autologous stem cell transplantation could be a safe therapeutic approach for all ELANE-CN patients.

Somatic Genetic Rescue Involving CSF3R and Other Novel Phosphothyrosine Kinase Receptor Mutations Occurring in Myeloid Malignancies

Somatic gene rescue (SGR), via acquisition and selection of somatic (SM) genetic hits, neutralizes functional defects resulting from hypomorphic germline (GL) mutations. However, this process may be maladaptive and lead to the development of leukemia. Acquisition of SM gain-of-function CSF3R mutations in the context of severe congenital neutropenia (SCN) illustrates such a scenario. Here, we further explored this and similar mechanisms in a cohort of 7121 adults with myeloid neoplasia and bone marrow failure (AML=1473, MDS=2248, other=3400). CSF3R mutations were found in 97 patients. In total, there were 37 and 56 patients with SM and GL mutations, respectively; biallelic GL and SM were 4. Among SM alterations, 18 were pathogenic or likely pathogenic including 8 nonsense truncating variants in class III isoform specific region of the cytoplasmic domain and 10 classical missense mutations in the juxtamembrane region, previously defined in the context of post-SCN AML and CNL. We thus hypothesized that these CSF3R SM mutations may also represent SGR in adult patients harboring hypomorphic GL variants and investigated the presence of SCN-associated alterations ( ELANE, WAS, GFI1) and in other phosphothyrosine kinase receptors (PTKR) such as CSF1R, CSF2RA, CSF2RB, FLT3 and KIT. Indeed, we found biallelic WAS p.D264H GL and CSF3R p.A119T SM in a patient with aplastic anemia (AA). Biallelic CSF3R were present in 4 patients: a) p.Q749X GL withp.M696T SM, b) E835K GL with p.T618I SM, c) p.Y752X GL withp.Q754E SM and d) biallelic p.Y752X GL with p.Q754E GL configuration with T615A SM. Compound heterozygous configuration of CSF3R SM included CSF1R SM variants( CSF3R p.M696T SM & CSF1R p.R294Q GL in a 64 year old. patient with MPN, CSF3R p.M696T SM & CSF1R c.1626+3G>A GL in a 61 year old patient with MDS) and CSF2RB ( CSF3R p.T618I SM & CSF2RB p.V890I GL in a 69 year old female patient with AML with leukopenia). When we analyzed the remaining 66 GL CSF3R variants in 56 carriers (in addition to the aforementioned biallelic combinations), we identified 9 compound heterozygous mutants involving CSF1R SM (n=1), CSF2RA (n=1), CSF2RB (n=3), FLT3(TKD/ITD, n=4/1). Specifically, we found the following configurations and disease associations: a) CSF3R p.V372E GLCSF2RB p.P842L SM in a 49 yo. AA patient who subsequently developed AML with FLT3 TKD, b) MDS patients with CSF3R p.E149 GLCSF1R p.G413S SM, c) CSF3R p.R440Q GL& CSF2RA p.R164Q SM and d) CSF3R p.E405K GL& CSF2RB c.1152+6G>A SM and e) AML patients with CSF3R p.E405K GL& CSF2RB p.R432C SM; f) CSF3R p.L619S GLandg,h)2 AML cases with CSF3R p.E808K GL of which all 3 acquired compound heterozygosity with FLT3 TKD, i) CSF3R p.E808K GLCSF3R p.E835K GL in a 71 year old patient with MDS with FLT3ITD AML. In addition to FLT3 GOF mutations, the most common SM hits observed in CSF3RGLcarriers were ASXL1 (n=12), TET2 (n=12), and SF3B1 (n=12). Identification of somatic and GL alterations in PTKR genes other than CSF3R, led us to systematically analyze these genes as targets of GL and SM CSF3R alterations. In total, we identified 72 GL and 73 SM CSF1R variants, 7 SM and 19 GL CSF2RA and 47 GL and 69 SM CSFR2B. Among these, we found 3 patients with compound heterozygous CSF2RBSMCSF3RGL, one with CSF2RBGLCSF3RGLas described above. We also identified one patient with CSF2RASMCSF3RGL. Finally, we identified two patients with CSF1RGL and CSF3RSM, and one with CSF1RSMCSF3RGLmutations. In summary, our study provides evidence for a tremendous complexity of interaction between less penetrant GL alterations of receptor genes and somatic GOF mutations, which may in some instances, correspond to the result of SGR. It is likely that the degree of LOF corresponds to the selection pressure for somatic rescue lesions.

Mavorixafor for Patients with Chronic Neutropenic Disorders Treated with G-CSF: Preliminary Response Data and G-CSF Dose Reduction in an Ongoing Phase 2, Open-Label, Multicenter Study Support Reduction in G-CSF Dosing

Introduction: Chronic neutropenia (CN) encompasses multiple disorders characterized by an absolute neutrophil count (ANC) <1500 cells/µL for >3 months, leading to increased susceptibility to recurrent and/or severe infections. CN can be sub-classified as congenital neutropenia defined by genetic variants ( ELANE variants are the most common), cyclic neutropenia (CyN) supported by documentation of ANC cycling with reciprocal monocytosis most often associated with certain ELANE variants, or chronic idiopathic neutropenia (CIN) defined as acquired neutropenia without an identifiable cause. The current treatment approach for CN involves long-term use of injectable granulocyte colony-stimulating factor (G-CSF), which can have associated adverse events (AEs) [Donadieu J. Expert Rev Hematol. 2021; Fioredda F. Hemasphere. 2023; Newburger PE. Semin Hematol. 2013]. Therefore, efforts are under way to discover other therapies for CN. In a phase 3 trial (NCT03995108), mavorixafor, an investigational oral CXCR4 antagonist, showed durable increases in ANC and reduction in total infection rate and severity in people with WHIM (Warts, Hypogammaglobulinemia, Infections, and Myelokathexis) syndrome [Badolato R. Clin Immunol. 2023]. Mavorixafor is being studied in a phase 2 trial for chronic neutropenic disorders (NCT04154488) [Warren JT. Blood. 2022] to evaluate the durability, safety, and tolerability of chronic dosing of mavorixafor with or without concurrent G-CSF. Here, we describe preliminary results for 3 participants in the ongoing phase 2 trial. Methods: Individuals (aged ≥12 years) with diagnosis of congenital neutropenia, CyN, or CIN ≥6 months prior and ANC <1000/µL (or no lower limit but <10,000/µL if on G-CSF) at screening visits were enrolled in the phase 2 trial. Eligible adult participants received once-daily 400 mg of mavorixafor while adolescents received weight-based dosing (>50 kg, 400mg; ≤50 kg, 200 mg) for 6 months with or without G-CSF. Participants already on G-CSF continued their individualized G-CSF dosing for ≥8 weeks, followed by potential dose and/or frequency reduction based on monthly ANC assessments. Hematologic parameters, including ANC, were assessed over 8 hours on day 1 and at months 1 and 3, with continued assessment at month 6. At months 2 and 4 (assessment to continue at month 5), hematologic parameters were assessed within 2 to 4 hours of dosing to reduce trial burden. Results: Data are reported as of July 17, 2023. Preliminary data from the first 3 participants on G-CSF receiving chronic once-daily oral mavorixafor for at least 2 months showed increases in mean ANC compared with baseline (BL) at all time points assessed in all participants. ANCs reached normal ranges for all participants. Increases in ANC supported physicians' decisions to reduce G-CSF dosing. Two participants (P1 and P2) with CIN achieved increases in ANC that enabled initiation of G-CSF tapering at month 2. For P1, G-CSF dose was tapered to 50% at month 2, and further G-CSF tapering occurred at month 3. ANC remained within normal ranges during this period. At month 4, G-CSF dosing was fully withdrawn, and the participant continued daily mavorixafor monotherapy. For P2, ANC increased ~3x baseline by month 2. G-CSF dose was tapered to 50% after month 2. ANC remained within normal ranges during this period. At month 3, G-CSF dosing was fully withdrawn, and the participant continued daily mavorixafor monotherapy with an ANC ~1000 cells/µL. A third participant (P3) with CyN receiving mavorixafor daily with concurrent G-CSF showed increases in ANC over BL for 4 months. All 3 participants remain on study, and have not experienced any serious AEs Conclusions: Our report shows that chronic treatment with oral, once-daily mavorixafor in combination with G-CSF resulted in durable increases in ANC compared with BL for ≥3 months in 3 study participants. Reduction of injectable G-CSF dosing was implemented in 2 study participants with CIN following robust ANC increase observed after the first 2 months of combination treatment. These preliminary data also support the safety of concomitant treatment with G-CSF and mavorixafor. Additional data from the ongoing phase 2 study will further elucidate the potential of daily, oral mavorixafor as a treatment for CN to reduce the burden and associated AEs of injectable G-CSF. A phase 3 trial of people with CN is being planned.

Differential transcriptional control of hematopoiesis in congenital and cyclic neutropenia patients harboring ELANE mutations.

Mutations in the ELANE gene, encoding the neutrophil elastase (NE) protein, are responsible for most cyclic neutropenia (CyN) cases and approximately 25% of congenital neutropenia (CN) cases. In CN and in CyN, a median of 2.8% of CD34+ cells were early CD49f+ hematopoietic stem cells (eHSC) that did not express ELANE and thus escape from the unfolded protein response (UPR) caused by mutated NE. In CyN, the CD49f+ cells respond to granulocyte colony-stimulating factor (G-CSF) with a significant upregulation of the hematopoietic stem cell-specific transcription factors, C/EBPα, MLL1, HOXA9, MEIS1, and HLF during the ascending arm of the cycle, resulting in the differentiation of myeloid cells to mature neutrophils at the cycle peak. However, NE protein released by neutrophils at the cycle's peak caused a negative feedback loop on granulopoiesis through the proteolytic digestion of G-CSF. In contrast, in CN patients, CD49f+ cells failed to express mRNA levels of HSC-specific transcription factors mentioned above. Rescue of C/EBPα expression in CN restored granulopoiesis.

Severe congenital neutropenia caused by the elane gene mutation in a 4-year-old vietnamese girl

ABSTRACT Severe congenital neutropenia (SCN) is an exceptionally rare genetic disorder associated with life-threatening bacterial infections. Among the several genetic variations related to SCN, heterozygous mutations in the ELANE gene encoding neutrophil elastase account for approximately 40 - 55% of the genetic causes. Herein, we present the first documented case of SCN in a Vietnamese girl from the Central region of Vietnam. The diagnosis was confirmed through genetic analysis of the ELANE gene, a known causative gene in SCN. The patient exhibited severe neutropenia and a history of recurrent infections that did not respond well to treatment. Treatment involved the administration of granulocyte-stimulating factor (G-CSF) and antibiotics, resulting in a successful increase in neutrophil counts. This report contributes to the understanding of SCN’s clinical presentation, diagnosis, and management, particularly in regions with limited documented cases.

Human 'knockouts' of CSF3 display severe congenital neutropenia.

Colony-stimulating factor 3 (CSF3) is a key factor in neutrophil production and function, and recombinant forms have been used clinically for decades to treat congenital and acquired neutropenia. Although biallelic inactivation of its receptor CSF3R is a well-established cause of severe congenital neutropenia (SCN), no corresponding Mendelian disease has been ascribed to date to CSF3. Here, we describe three patients from two families each segregating a different biallelic inactivating variant in CSF3 with SCN. Complete deficiency of CSF3 as a result of nonsense-mediated decay (NMD) could be demonstrated on RT-PCR using skin fibroblasts-derived RNA. The phenotype observed in this cohort mirrors that documented in mouse and zebrafish models of CSF3 deficiency. Our results suggest that CSF3 deficiency in humans causes a novel autosomal recessive form of SCN.

SGLT5 is the renal transporter for 1,5-anhydroglucitol, a major player in two rare forms of neutropenia

Neutropenia and neutrophil dysfunction in glycogen storage disease type 1b (GSD1b) and severe congenital neutropenia type 4 (SCN4), associated with deficiencies of the glucose-6-phosphate transporter (G6PT/SLC37A4) and the phosphatase G6PC3, respectively, are the result of the accumulation of 1,5-anhydroglucitol-6-phosphate in neutrophils. This is an inhibitor of hexokinase made from 1,5-anhydroglucitol (1,5-AG), an abundant polyol in blood. 1,5-AG is presumed to be reabsorbed in the kidney by a sodium-dependent-transporter of uncertain identity, possibly SGLT4/SLC5A9 or SGLT5/SLC5A10. Lowering blood 1,5-AG with an SGLT2-inhibitor greatly improved neutrophil counts and function in G6PC3-deficient and GSD1b patients. Yet, this effect is most likely mediated indirectly, through the inhibition of the renal 1,5-AG transporter by glucose, when its concentration rises in the renal tubule following inhibition of SGLT2. To identify the 1,5-AG transporter, both human and mouse SGLT4 and SGLT5 were expressed in HEK293T cells and transport measurements were performed with radiolabelled compounds. We found that SGLT5 is a better carrier for 1,5-AG than for mannose, while the opposite is true for human SGLT4. Heterozygous variants in SGLT5, associated with a low level of blood 1,5-AG in humans cause a 50–100% reduction in 1,5-AG transport activity tested in model cell lines, indicating that SGLT5 is the predominant kidney 1,5-AG transporter. These and other findings led to the conclusion that (1) SGLT5 is the main renal transporter of 1,5-AG; (2) frequent heterozygous mutations (allelic frequency > 1%) in SGLT5 lower blood 1,5-AG, favourably influencing neutropenia in G6PC3 or G6PT deficiency; (3) the effect of SGLT2-inhibitors on blood 1,5-AG level is largely indirect; (4) specific SGLT5-inhibitors would be more efficient to treat these neutropenias than SGLT2-inhibitors.

The Molecular and Genetic Mechanisms of Inherited Bone Marrow Failure Syndromes: The Role of Inflammatory Cytokines in Their Pathogenesis.

Inherited bone marrow failure syndromes (IBMFSs) include Fanconi anemia, Diamond-Blackfan anemia, Shwachman-Diamond syndrome, dyskeratosis congenita, severe congenital neutropenia, and other rare entities such as GATA2 deficiency and SAMD9/9L mutations. The IBMFS monogenic disorders were first recognized by their phenotype. Exome sequencing has validated their classification, with clusters of gene mutations affecting DNA damage response (Fanconi anemia), ribosome structure (Diamond-Blackfan anemia), ribosome assembly (Shwachman-Diamond syndrome), or telomere maintenance/stability (dyskeratosis congenita). The pathogenetic mechanisms of IBMFSs remain to be characterized fully, but an overarching hypothesis states that different stresses elicit TP53-dependent growth arrest and apoptosis of hematopoietic stem, progenitor, and precursor cells. Here, we review the IBMFSs and propose a role for pro-inflammatory cytokines, such as TGF-β, IL-1β, and IFN-α, in mediating the cytopenias. We suggest a pathogenic role for cytokines in the transformation to myeloid neoplasia and hypothesize a role for anti-inflammatory therapies.

Application of the salivary multi test in children with severe congenital neutropenia: A case report

A Salivary Multi Test® (SMT®) was used in children with severe congenital neutropenia who were admitted to the pediatrics department of our hospital. SMT® was conducted on three patients with severe congenital neutropenia. Rod and segmented neutrophil counts in the peripheral blood showed fluctuations similar to those of the “leukocyte level” in SMT®. SMT®, which uses saliva samples that are non-invasive and can be easily collected, may help manage systemic diseases.

Lack of eosinophil extracellular trap formation due to failure of plasma membrane breakdown in the absence of elastase

AbstractActivated eosinophils are described to release eosinophil extracellular traps (EETs), which consist of the cell’s DNA covered with granule-derived antimicrobial peptides. Upon stimulation of eosinophils with the known EET-inducers phorbol 12-myristate 13-acetate, monosodium urate crystals, or Candida albicans, we observed that their plasma membrane became compromised, resulting in accessibility of the nuclear DNA for staining with the impermeable DNA dye Sytox Green. However, we did not observe any DNA decondensation or plasma membrane rupture by eosinophils, which sharply contrasts with neutrophil extracellular trap (NET) formation and the subsequent cell death known as NETosis. Neutrophil elastase (NE) activity is thought to be essential for the cleavage of histones and chromatin decondensation during NETosis. We observed that the neutrophils of a patient with a mutation in ELANE, leading to congenital neutropenia and NE deficiency, were unable to undergo NETosis. Taken together, we may suggest that the natural absence of any NE-like proteolytic activity in human eosinophils explains why EET formation is not observed, even when eosinophils become positive for an impermeable DNA dye in response to stimuli that induce NETosis in neutrophils.

1364-P: Cinicoradiological and Microbial Spectrum of Skull Base Osteomyelitis and Its relation to Diabetes Mellitus

Skull base osteomyelitis (SBO) is a rare life-threatening disease, which is on the increase specifically the incidence of fungal skull base osteomyelitis. Objectives: To describe the demographic, and clinicoradiological profile, and to assess the outcome of skull base osteomyelitis. Methodology: A prospective study from a tertiary care centre, in Kerala from 1st February 2018 to 31st August 2019 with a minimum follow-up of 6 months. All patients diagnosed with skull base osteomyelitis were included. The demographic profile and relevant investigations, radiological correlations and treatment outcomes were analysed. Results and Discussions: 30 patients (23 males and 7 females) were studied. Incidence was found to be high in the age group 51-60 years. The mean (SD) of Age (Years) was 62.02 (14.21), ranging from 1.5-78 years. The most common presentation was a nocturnal earache (86.7%).13.3% of patients presented with headache alone, these cases were diagnosed to be central skull base osteomyelitis and had a significant association with clival erosion. All the patients were having diabetes mellitus except 1.5 yrs old who had congenital cyclic neutropenia. We could see an association between uncontrolled blood glucose and the severity of the disease (P value <0.001). 63.3% of the participants had Cranial Nerve Palsy at the presentation. The culture yielded Pseudomonas followed by staphylococcus aureus, MRSA & Aspergillus. The ESR and CRP levels were reliable for the detection, progression and resolution of disease status in SBO. All patients were treated with third-generation cephalosporins and fluoroquinolones for a minimum of 6 weeks and of which, 12 patients with fungal SBO were given antifungals also. Conclusions: Skull base osteomyelitis is an entity that requires a lifelong commitment. A high index of suspicion, early diagnosis, and prompt and aggressive management are critical for a positive outcome. Uncontrolled diabetes mellitus was the risk factor recognised. Disclosure S.Radhakrishnan: None. D.C: None. V.Dahiya: None. C.R: None.

Severe congenital neutropenia due to G6PC3 deficiency: early and delayed phenotype of a patient

BackgroundSevere Congenital Neutropenia type 4 (SCN4), is a rare autosomal recessive condition, due to mutations in the G6PC3 gene. The phenotype comprises neutropenia of variable severity and accompanying anomalies.Case presentationWe report a male patient with confirmed G6PC3 deficiency presented with recurrent bacterial infections and multi-systemic complications. Our case was the first with a novel homozygous frameshift mutation in G6PC3. The patient demonstrated large platelets on his peripheral blood smear which is a rare presentation of this disease.ConclusionAs SCN4 patients could be easily missed, it is recommended to consider G6PC3 mutation for any case of congenital, unexplained neutropenia.

Genetics and pathophysiology of severe congenital neutropenias (SCNs)

Genetics and pathophysiology of severe congenital neutropenias (SCNs)

Prevalence and clinical expression of germ line predisposition to myeloid neoplasms in adults with marrow hypocellularity

AbstractSystematic studies of germ line genetic predisposition to myeloid neoplasms in adult patients are still limited. In this work, we performed germ line and somatic targeted sequencing in a cohort of adult patients with hypoplastic bone marrow (BM) to study germ line predisposition variants and their clinical correlates. The study population included 402 consecutive adult patients investigated for unexplained cytopenia and reduced age-adjusted BM cellularity. Germ line mutation analysis was performed using a panel of 60 genes, and variants were interpreted per the American College of Medical Genetics and Genomics/Association for Molecular Pathology guidelines; somatic mutation analysis was performed using a panel of 54 genes. Of the 402 patients, 27 (6.7%) carried germ line variants that caused a predisposition syndrome/disorder. The most frequent disorders were DDX41-associated predisposition, Fanconi anemia, GATA2-deficiency syndrome, severe congenital neutropenia, RASopathy, and Diamond-Blackfan anemia. Eighteen of 27 patients (67%) with causative germ line genotype were diagnosed with myeloid neoplasm, and the remaining with cytopenia of undetermined significance. Patients with a predisposition syndrome/disorder were younger than the remaining patients and had a higher risk of severe or multiple cytopenias and advanced myeloid malignancy. In patients with myeloid neoplasm, causative germ line mutations were associated with increased risk of progression into acute myeloid leukemia. Family or personal history of cancer did not show significant association with a predisposition syndrome/disorder. The findings of this study unveil the spectrum, clinical expressivity, and prevalence of germ line predisposition mutations in an unselected cohort of adult patients with cytopenia and hypoplastic BM.

HAX1-related congenital neutropenia: Long-term observation in paediatric and adult patients enrolled in the European branch of the Severe Chronic Neutropenia International Registry (SCNIR).

HAX1-related congenital neutropenia (HAX1-CN) is a rare autosomal recessive disorder caused by pathogenic variants in the HAX1 gene. HAX1-CN patients suffer from bone marrow failure as assessed by a maturation arrest of the myelopoiesis revealing persistent severe neutropenia from birth. The disorder is strongly associated with severe bacterial infections and a high risk of developing myelodysplastic syndrome or acute myeloid leukaemia. This study aimed to describe the long-term course of the disease, the treatment, outcome and quality of life in patients with homozygous HAX1 mutations reported to the European branch of the Severe Chronic Neutropenia International Registry. We have analysed a total of 72 patients with different types of homozygous (n = 68), compound heterozygous (n = 3), and digenic (n = 1) HAX1 mutations. The cohort includes 56 paediatric (<18 years) and 16 adult patients. All patients were initially treated with G-CSF with a sufficient increase in absolute neutrophil counts. Twelve patients required haematopoietic stem cell transplantation for leukaemia (n = 8) and non-leukaemic indications (n = 4). While previous genotype-phenotype reports documented a striking correlation between two main transcript variants and clinical neurological phenotypes, our current analysis reveals novel mutation subtypes and clinical overlaps between all genotypes including severe secondary manifestations, e.g., high incidence of secondary ovarian insufficiency.

P133 - Topic: AS08-Treatment/AS08d-New developments – Preclinical studies: DEVELOPMENT OF APTAMERS AS THERAPY FOR CONGENITAL NEUTROPENIA DISEASES

P133 - Topic: AS08-Treatment/AS08d-New developments – Preclinical studies: DEVELOPMENT OF APTAMERS AS THERAPY FOR CONGENITAL NEUTROPENIA DISEASES

JAGN1 mutation with distinct clinical features; two case reports and literature review

Jagunal homolog 1 (JAGN1) has been recognized as an essential protein in neutrophil function. The mutated JAGN1 is responsible for immunodeficiency related to innate and humoral defense mechanisms. This deficiency impairs neutrophil development and function, leading to recurrent infections and facial dysmorphism as phenotypic consequences of severe congenital neutropenia (SCN). We report two siblings having the reported JAGN1 mutation with different clinical manifestations. Recurrent abscess formation unresponsive to antibiotic therapy, a history of delayed umbilical separation, frequent bacterial or fungal infection, dysmorphic face, failure to thrive, and other coexisting organ abnormalities should prompt physicians to syndromic immunodeficiencies involving neutrophils. Genetic investigations to elucidate the responsible mutation is critical as clinical management varies. Once the diagnosis is confirmed, a multi-disciplinary team should perform further workups to investigate other coexisting malformations and neurodevelopmental evaluation.

Historical Cohort of Severe Congenital Neutropenia in Iran: Clinical Course, Laboratory Evaluation, Treatment, and Survival.

Severe congenital neutropenia (SCN) is one of the primary immunodeficiency diseases developed by genetic alterations. Mutations in several genes including HAX-1 , G6PC3 , jagunal , and VPS45 account for autosomal recessive SCN. Patients with SCN registered in the Iranian Primary Immunodeficiency Registry and referred to our clinic at the Children's Medical Center were reviewed. Thirty-seven eligible patients with a mean age of 28.51 ± 24.38 months at the time of diagnosis were included. Nineteen cases had consanguineous parents and 10 cases had confirmed or unconfirmed positive family history. The most prevalent infectious symptoms were oral infections followed by respiratory infections. We identified HAX-1 mutation in 4, ELANE mutation in 4 cases, G6PC3 mutation in 1, and WHIM syndrome in 1 case. Other patients remained genetically unclassified. After the median follow-up of 36 months from the time of diagnosis, the overall survival was 88.88%. The mean event-free survival was 185.84 months (95% CI: 161.02, 210.66). Autosomal recessive SCN is more common in countries with high rates of consanguinity like Iran. The genetic classification was possible only for a few patients in our study. This might suggest that there are other autosomal recessive genes causative of neutropenia that have yet to be described.

Tratamiento anestésico de la neuromiotonía. Descripción de un caso

The importance of neutrophils in fighting infections is clearly evidenced by “Experiments of Nature,” in which various gene mutations cause quantitative and qualitative abnormalities in the neutrophils. In such conditions, patients will suffer from infancy with life-threatening infections that must be treated promptly. In many cases delay in diagnosis and therapy may have serious consequences including death. This article focuses on severe congenital neutropenia, chronic granulomatous disease, leukocyte adhesion defects, and leukocyte motility abnormalities—all conditions that are related to congenital defects of the phagocytes.