Novel Munc13-4 Mutations in Patients with Hemophagocytic Lymphohistiocytosis.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2807-2807
Author(s):  
Alessandra Santoro ◽  
Sonia Cannella ◽  
Antonino Trizzino ◽  
Cesare Danesino ◽  
Daniela Pende ◽  
...  

Abstract Familial hemophagocytic Lymphohistiocytosis (FLH) is a rare disorder characterized by fever, hepatosplenomegaly, cytopenia, hypertriglyceridemia, hypofibrinogenemia and reduced natural killer (NK) cell activity. Several genetic defects have been recognized as associated with FHL. After identification of perforin gene (PRF1) mutation as the cause of about one third of cases of FHL (Stepp,1999), in 2003 the same group reported that another gene involved in cellular cytotoxicity, Munc13-4, encoding for a protein involved in granule release in cytotoxic lymphocyte, is associated with a subset of patients with FHL. We have analyzed for Munc13-4 mutations 16 families of patients diagnosed with FHL according to current criteria, in whom PRF1 mutations had been excluded; 14 were Italian, 1 from USA, one from UK. The 32 exons and their proximal flanking regions of Munc13-4 gene were amplified from genomic DNA and amplification products were directly sequenced by cycle sequencing approach (BigDye Terminator Applied Biosystems). Sequences of primers utilized for the amplification reactions were designed with dedicated software (Primer Express) according to the gene sequence retrived from Genebank. A total of 13 mutations were identified in 12 families; 3 had homozygous mutations, 5 had combined heterozygous mutations, and 4 had only one detectable mutated allele. Mutation 753+IG in exon 9 (splice donor site) had been already reported (Feldman 2003, zurStadt 2005); The following novel mutations were found: G175A in exon 3 (A59T), delC532 in exon 6 (178 fs), A610G in exon 7 (M204V), G1241T in exon 14 (R414L), A1847G in exon 20 (E616G), del GGAG 2346 (782 fs) in exon 24, A2599G (K867E) in exon 27, C2650T in exon 28 (Q884stop), C2782T in exon 29 (R928C), C2896T in exon 30 (R966W), 3082delC in exon 31 (1028fs), insG3226 in exon 32 (1076fs). Mutation A2599 was observed in 6 families; mutation A1847G in 3 families; C2782T and G1241T in 2 families. We have also identified the polymorphisms C279T, and A3198G. Mutations were scattered over different exons and almost entirely different from those reported so far. A2599G mutation was frequently observed and its role deserves further investigation. Screening of Munc13-4 mutations is a powerful tool to confirm the diagnosis, to refine the therapeutic choice including indication to HSCT, selection of familiar donor, and identification of carriers and prenatal diagnosis in most of the families with FHL not associated with PRF1 mutations. Due to lack of immunologic or flow-cytometric tools for rapid screening of Munc13-4 defective patients, the high number of coding exons and lack of mutation clustering, screening of Munc13-4 mutations, although expensive and time consuming, remains necessary and allowed us to identify the genetic defect in the majority of our patients with FHL not associated with PRF1 mutations.

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
Eric Olinger ◽  
Intisar Al Alawi ◽  
Elisa Molinari ◽  
Eissa Ali Faqeih ◽  
Mohamed Al Hamed ◽  
...  

Abstract Background and Aims Whole exome sequencing (WES) is becoming part of routine clinical and diagnostic practice and has been extensively applied in research studies as well as for diagnostic utility to detect various novel genes and variants. Filtering of variants and scoring variants in terms of pathogenicity still represents a major challenge and may explain why ∼50% of patients remain without diagnosis after initial assessment. Method In this study, we performed WES to determine the genetic cause of a hepato-renal ciliopathy syndrome in a genetically unsolved consanguineous family from Oman with 2 affected children. For variants filtering and annotation Qiagen Clinical Insight tool was used. Database searches for identical alleles in patients with similar phenotypes were performed using Genomics England, UK Biobank and a Saudi Arabian cohort. RNA studies were used to confirm a splicing defect. This research was made possible through access to the data and findings generated by the 100,000 Genomes Project and from UK Biobank, a major biomedical database. Results Initial bioinformatic analysis of WES data from 2 affected sibs excluded obvious pathogenic variants in known genes associated with primary ciliopathy syndromes with liver and kidney phenotypes. However, by manual curation of variants in candidate genes, a rare homozygous synonymous allele in NPHP3 was identified (c.2805C>T; p.(Gly935Gly)), mid-exon 20 and within a region of shared homozygosity on chromosome 3. Correct segregation was confirmed via Sanger sequencing in the parents and the 2 affected sibs. The variant was rare in gnomAD (2/251374 alleles) and was found heterozygously in just one individual within the UK Biobank cohort of 200,000 exomes. Using various in silico tools, the allele was shown to activate a cryptic splice donor site in the middle of exon 20. RT-PCR with sequencing of parental whole blood RNA confirmed alternative splicing leading to frameshift p.Gly935GlyfsTer47. The identical homozygous allele was identified in 2 additional unsolved families within the Genomics England 100,000 Genomes Project and in 1 Saudi Arabian family with similar hepato-renal phenotypes. Conclusion This study shows that automated filtering of WES data may exclude synonymous variants which are pathogenic, especially if they are mid-exon. Here we identified a recurrent synonymous NPHP3 variant leading to a splice defect as the cause of a hepato-renal ciliopathy phenotype in four families. In unsolved cases, rare synonymous alleles in candidate genes need to be reassessed for impact on RNA splicing and possible pathogenicity.


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 3552-3552
Author(s):  
Zhao Wang ◽  
Yini Wang ◽  
Cuicui Feng ◽  
Liping Tian

Abstract Acquired hemophagocytic lymphohistiocytosis (HLH) is a life threatening condition characterized by uncontroling hyperinflammation on the basis of various infection, tumor and inherited immune deficiency. Awareness of the clinical symptoms and of the diagnostic criteria of HLH is crucial in order not to overlook HLH and to start life-saving therapy in time. In this study, we reviewed 57 suspected HLH patients from March 2006 to June 2008. 25 healthy subjects were enrolled in the study as control. NK cell activity in peripheral blood was tested by a released LDH assay. Meanwhile, solution interleukin-2 receptor (sCD25) was examined with ELISA double antibody sandwich assay. The level of glycosylated ferritin was also detected and the ratio of glycosylated ferritin to ferritin was determined. 41 out of 57 patients were definitely diagnosed according to HLH-2004 diagnostic criteria in this study and 16 patients were excluded. We found that the level of NK cell activity and the ratio of glycosylated ferritin in the all 41 final diagnozed HLH patients were significantly lower than those in the 16 excluded patients and 25 healthy control subjects (p<0.01). Meanwhile, the level of sCD25 in peripheral blood was much higher in all the 41 HLH patients than that in the excluded and healthy people (p<0.05). We compared the coincidence of each diagnostic index in the 41 HLH patients before and after final diagnosis. It was found that 100% patients had abnormal expression on NK cell activity, sCD25 and glycosylated ferritin in the early disease. The three diagnostic indexes were more sensitive and specific than other indexes, such as fever, hepatosplenomegaly, cytopenia, hyper-triglyceridemia, hypo-fibrinogenemia. 41 diagnosed patients received the regimen containing methylprednisolone and immunoglobulin, with or without fludarabine, 26 out of 41 were markedly improved after treatment, 10 out of 41 were exacerbated, and other 5 patients gave up treatment. It is concluded that detection of NK cell activity, sCD25 and glycosylated ferritin may play a very important role in the early diagnosis of HLH. Our data also suggest that fludarabine combined with methylprednisolone and immunoglobulin (FDIg) may provide a new viewpoint for HLH therapy.


Blood ◽  
2007 ◽  
Vol 110 (6) ◽  
pp. 1906-1915 ◽  
Author(s):  
Yenan T. Bryceson ◽  
Eva Rudd ◽  
Chengyun Zheng ◽  
Josefine Edner ◽  
Daoxin Ma ◽  
...  

Abstract Familial hemophagocytic lymphohistiocytosis (FHL) is typically an early onset, fatal disease characterized by a sepsislike illness with cytopenia, hepatosplenomegaly, and deficient lymphocyte cytotoxicity. Disease-causing mutations have been identified in genes encoding perforin (PRF1/FHL2), Munc13-4 (UNC13D/FHL3), and syntaxin-11 (STX11/FHL4). In contrast to mutations leading to loss of perforin and Munc13-4 function, it is unclear how syntaxin-11 loss-of-function mutations contribute to disease. We show here that freshly isolated, resting natural killer (NK) cells and CD8+ T cells express syntaxin-11. In infants, NK cells are the predominant perforin-containing cell type. NK cells from FHL4 patients fail to degranulate when encountering susceptible target cells. Unexpectedly, IL-2 stimulation partially restores degranulation and cytotoxicity by NK cells, which could explain the less severe disease progression observed in FHL4 patients, compared with FHL2 and FHL3 patients. Since the effector T-cell compartment is still immature in infants, our data suggest that the observed defect in NK-cell degranulation may contribute to the pathophysiology of FHL, that evaluation of NK-cell degranulation in suspected FHL patients may facilitate diagnosis, and that these new insights may offer novel therapeutic possibilities.


Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 4615-4615 ◽  
Author(s):  
Bhagirathbhai Dholaria ◽  
William A Hammond ◽  
Amanda Shreders ◽  
Sarah Robinson ◽  
Taimur Sher

Abstract Background Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening systemic inflammatory condition. Due to rarity of the cases, it presents difficulties in diagnosis and management. Survival remains poor despite aggressive chemotherapy. Objective Patient outcomes varied markedly despite standardize therapy. Reliable prognostic disease markers may help to tailor intensity of therapy and predict long term outcomes. We attempt to look for variables associated with difference in mortality within 30 days of diagnosis. Methods We performed a retrospective search on mayo clinic patient database for the patients with the diagnosis of HLH from 2005 to 2015. HLH-04 criteria were used to select the study population. Patients were divided in two groups based on survival after the diagnosis. We analyzed different clinical and laboratory parameters to detect difference between the patients expired within 30 days of diagnosis and who survived longer than 30 days. Baseline Characteristics: Demographics: 40 patients were included in the analysis who met HLH- 04 criteria. Mean age was 49 years, 40% (16/40) were female and 60% (24/40) were male. Underlying HLH etiology was malignancy 37% (15/40), infection 20% (8/40), rheumatological 17% (7/40), idiopathic 20% (8/40). Two patients were peripartum and one with Kikuchi syndrome. EBV DNA PCR were positive in 32% (13/40) of patients. Table 1 show clinical and laboratory characteristics according to HLH-04 criteria. Treatment: Steroids were used in 92% (37/40), etoposide was used in 55% (22/40), and HLH 04 protocol (Etoposide/dexamethasone/cyclosporine) was used in 40% (16/40) of the patients. IVIG was used in 13% with underlying rheumatological process. Mean follow up was 57 weeks (0.1 to 336 weeks) for the whole group. Total 40% (16/40) died within 30 days of diagnosis. Results Risk of 30-days mortality was significantly higher in the patients with ferritin >5000 mcg/L at the time of diagnosis and age > 55 years. Out of total 40 patients, 54% (12/22) died in ferritin >5000mcg/L group and 22% (4/18) died in ferritin < 5000 mcg/L group within 30 days. (p-0.03) Death rate within 30 days was 65% (11/17) with age > 55 years and 22% (5/23) with age < 55 years at the time of diagnosis of HLH. (p-0.05) No difference between the groups in terms of gender, EBV positivity, underlying etiology and etoposide use was found in 30 days mortality. Table 2 summarizes the findings. Discussion HLH is a complex disorder with significant heterogeneity in terms of underlying etiology and response to treatments. Diagnosis is based on a set of clinical and investigational parameters. Most commonly used criteria are HLH-04. Treatment involves rapid immunosuppression with steroids, chemotherapy and calcineurin inhibitors. Previous retrospective studies have pointed out different risk factors associated with poor survival, which are malignancy, hypoalbuminemia, elevated creatinine and bilirubin. Ours is a relatively small retrospective analysis, but it shows significant prognostic value to elevated ferritin (>5000 mcg/L) at the time of diagnosis and age > 55 years. Survival remains poor in high risk patients despite aggressive therapy. Biological agents (IL1 and IL6 blockage) may provide new realm of therapy with tolerable toxicity profile. Conclusion Elevated ferritin at the time of diagnosis and older age are associated with significant risk of 30 day mortality in HLH. These factors can be incorporated in future clinical trials to choose different treatment pathways. Table. Clinical and laboratory characteristics according to HLH- 04 criteria Clinical/laboratory manifestation Presence of HLH 04 criteria (%) Fever > 38.5C 36/40 90 Splenomegaly 30/40 75 Hemoglobin < 9g/dl 22/40 55 ANC < 1000/microL 14/40 35 Platelets < 100, 000/microL 31/40 77 Triglyceride > 265 mg/dl 22/40 55 Ferritin > 500 mcg/L 36/40 90 Fibrinogen <150 mg/dl 12/38 31 sIL2- R > 1000u/ml 13/14 92 Low NK - cell activity 13/15 86 Presence of hemophagocytosis 33/39 84 Table 2. Difference in clinical variables based on survival after the diagnosis of HLH Survival < 30 days Survival > 30 days P value Age (years) 62 40 0.0004 Median time to start treatment (weeks) 40.7 8.6 0.23 Baseline ferritin (mcg/L) 32866 10667 0.01 Peak ferritin (mcg/L) 45870 29894 0.26 Albumin (g/dL) 2.3 2.6 0.41 LDH (U/L) 1271 720 0.51 Bilirubin (mg/dL) 8.9 4.5 0.14 Triglyceride (mg/dl) 260 276 0.70 Disclosures No relevant conflicts of interest to declare.


2021 ◽  
Vol 39 (15_suppl) ◽  
pp. e19578-e19578
Author(s):  
Frances Natalia Cervoni-Curet ◽  
Adan Rios ◽  
Binoy Yohannan ◽  
Hongyu Miao

e19578 Background: Secondary HLH in adults is associated to infections, malignancies, and autoimmune disorders. HLH in children has been the basis for the management and treatment of HLH in adults. Despite their clinical similarities there are fundamental differences. Children’s HLH is caused by gene mutations in granule-mediated cytotoxicity while secondary HLH does not have known apparent genetic causes. This may affect the clinical outcomes based in how we approach the diagnosis and management of secondary HLH in adults. Methods: We reviewed 49 cases of secondary HLH at our institution over a five-year period. Patients median age was 47 years, with 31 males, 18 females. Fifteen were Caucasian, 10 Asians, 8 African American and 15 Hispanics. One was not specified. Results: Fever, hyperferritenemia and cytopenia correlated with 100% elevation of sCD25R, the most important biomarker of HLH. Patients with these three criteria were urgently treated with dexamethasone-etoposide (HLH-94 protocol) or dexamethasone alone (autoimmune related) while completing identification of other criteria described in the pediatric population together with treatment of the secondary cause. Conclusions: Secondary HLH is not rare. Etoposide and dexamethasone (preferred dose:40 mg total/day initially) are the most important current therapeutic approaches. Secondary HLH must be treated urgently and independently of the secondary cause. Treatment should not be delayed awaiting results of sCD25R, NK-cell activity and presence of hemophagocytosis in the bone marrow (often absent). Further work needs to be done to elucidate the physiopathology of secondary HLH.[Table: see text]


2021 ◽  
pp. jrheum.200941
Author(s):  
AnnaCarin Horne ◽  
Tatiana von Bahr Greenwood ◽  
Samuel C.C. Chiang ◽  
Marie Meeths ◽  
Caroline Björklund ◽  
...  

Objective Macrophage activation syndrome (MAS) constitutes one subtype of the hyperinflammatory syndrome hemophagocytic lymphohistiocytosis (HLH), and the term MAS-HLH was recently proposed for HLH with underlying autoimmune/autoinflammatory conditions. The mortality of MAS-HLH has been estimated to 5-10%. Here we report our experiences with moderately dosed etoposide in severe MAS-HLH, administered with the objective to effectively reduce severe hyperinflammatory activity with limited side effects. Methods In addition to conventional anti-inflammatory treatment, moderately dosed etoposide was administered to seven children affected by rapidly progressing MAS-HLH with central nervous system (n=5) and/or pulmonary (n=5) involvement. Three had underlying systemic onset juvenile idiopathic arthritis (sJIA), two atypical sJIA (no arthritis at diagnosis), and two systemic lupus erythematosus. We performed lymphocyte cytotoxicity analyses in all seven and genetic analyses in six. Results All children promptly responded to moderately dosed etoposide (50-100 mg/m2 once weekly), added to conventional MAS-HLH treatment which was considered insufficient. The mean accumulated etoposide dose was 671 mg/m2 (range 300-1,050 mg/m2), as compared to 1,500 mg/m2 recommended the first 8 weeks of the HLH-94/HLH-2004 protocols. One child developed neutropenic fever and another neutropenic sepsis (neutrophils 0.3x109/L at therapy onset). Five/seven children had low percentages (<5%) circulating NK-cells prior to or in association with diagnosis; NK-cell activity was pathologically low in two/five children studied. Disease-causing variants in HLH-associated genes were not found. All children were alive at latest follow-up (2-9 years after onset); neurological symptoms had normalized in four/five affected children. Conclusion Moderately dosed etoposide may be beneficial in severe and/or refractory MAS-HLH.


2018 ◽  
Vol 5 (suppl_1) ◽  
pp. S301-S301 ◽  
Author(s):  
Farhan Fazal ◽  
Naveet Wig ◽  
Manish Soneja ◽  
Dipendra K Mitra ◽  
Sk Panda ◽  
...  

Abstract Background Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening hyperinflammatory condition diagnosed by HLH 2004 criteria. This criterion has common clinical and laboratory features with sepsis and tropical fevers, but there is marked difference in management and outcome of these two entities. The study is conducted to know whether there is any difference in the clinico-laboratory features, management, and outcome of sepsis with or without secondary HLH. Methods This is a prospective observational study where patients presenting with sepsis and bicytopenia are included. The patients underwent relevant investigations according to 2004 HLH diagnostic criteria. The patients are divided into sepsis with or without HLH. The underlying etiology, treatment, and outcome of the two groups are analysed. Results Fifty sepsis patients are included in the study, out of which 28 fulfilled the HLH diagnostic criteria which comprised of 18 men and 10 women. The etiology were bacterial (three enteric fever, three tuberculosis, two scrub typhus, one Staphylococcal aureus), viral (one dengue fever, two HIV, two encephalitis), fungal (one aspergillosis, one mucormycosis, two others), parasites (three malaria, one leishmania) malignancy (two hodgkin lymphoma, one non-Hodgkins lymphoma), and unknown etiology in six patients, with &gt;1 etiology in three patients (Figure 2). The percentage of each criterion fulfilled in both groups is given in Figure 1, showing an increased occurrence of splenomegaly, low NK cell activity, hypertriglyceridemia in HLH patients. Steroids along with supportive treatment was given to 53% and etoposide was added in 7%. Treatment for underlying etiology alone without immunosuppressive treatment was given in 39%. The mortality in those with HLH vs. without HLH was 42% and 31%, respectively. The median duration of hospital stay was 18 and 36 days in HLH and without HLH group, respectively. Conclusion HLH should be suspected in sepsis patients with bicytopenia specially in tropical fevers. There is increased mortality if the sepsis patients fulfil HLH criteria. Early diagnosis and management is of paramount importance. Disclosures All authors: No reported disclosures.


Genes ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1489
Author(s):  
Gabriela Rudd Garces ◽  
Maria Elena Turba ◽  
Myriam Muracchini ◽  
Alessia Diana ◽  
Vidhya Jagannathan ◽  
...  

Dwarfism phenotypes occur in many species and may be caused by genetic or environmental factors. In this study, we investigated a family of nine Dogo Argentino dogs, in which two dogs were affected by disproportionate dwarfism. Radiographs of an affected dog revealed a decreased level of endochondral ossification in its growth plates, and a premature closure of the distal ulnar physes. The pedigree of the dogs presented evidence of monogenic autosomal recessive inheritance; combined linkage and homozygosity mapping assigned the most likely position of a potential genetic defect to 34 genome segments, totaling 125 Mb. The genome of an affected dog was sequenced and compared to 795 control genomes. The prioritization of private variants revealed a clear top candidate variant for the observed dwarfism. This variant, PRKG2:XM_022413533.1:c.1634 + 1G>T, affects the splice donor site and is therefore predicted to disrupt the function of the PKRG2 gene encoding protein, kinase cGMP-dependent type 2, a known regulator of chondrocyte differentiation. The genotypes of the PRKG2 variant were perfectly associated with the phenotype in the studied family of dogs. PRKG2 loss-of-function variants were previously reported to cause disproportionate dwarfism in humans, cattle, mice, and rats. Together with the comparative data from other species, our data strongly suggest PRKG2:c.1634+1G>T to be a candidate causative variant for the observed dwarfism phenotype in Dogo Argentino dogs.


2018 ◽  
Vol 24 (1) ◽  
pp. 57-67 ◽  
Author(s):  
Monica Salani ◽  
Fabio Urbina ◽  
Anthony Brenner ◽  
Elisabetta Morini ◽  
Ranjit Shetty ◽  
...  

Familial dysautonomia (FD) is an autonomic and sensory neuropathy caused by a mutation in the splice donor site of intron 20 of the ELP1 gene. Variable skipping of exon 20 leads to a tissue-specific reduction in the level of ELP1 protein. We have shown that the plant cytokinin kinetin is able to increase cellular ELP1 protein levels in vivo and in vitro through correction of ELP1 splicing. Studies in FD patients determined that kinetin is not a practical therapy due to low potency and rapid elimination. To identify molecules with improved potency and efficacy, we developed a cell-based luciferase splicing assay by inserting renilla (Rluc) and firefly (Fluc) luciferase reporters into our previously well-characterized ELP1 minigene construct. Evaluation of the Fluc/Rluc signal ratio enables a fast and accurate way to measure exon 20 inclusion. Further, we developed a secondary assay that measures ELP1 splicing in FD patient-derived fibroblasts. Here we demonstrate the quality and reproducibility of our screening method. Development and implementation of this screening platform has allowed us to efficiently screen for new compounds that robustly and specifically enhance ELP1 pre-mRNA splicing.


2021 ◽  
Vol 22 (6) ◽  
pp. 2967
Author(s):  
Raymond Chu ◽  
Charmaine van Eeden ◽  
Sneha Suresh ◽  
Wendy I. Sligl ◽  
Mohammed Osman ◽  
...  

The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has resulted in significant morbidity and mortality across the world, with no current effective treatments available. Recent studies suggest the possibility of a cytokine storm associated with severe COVID-19, similar to the biochemical profile seen in hemophagocytic lymphohistiocytosis (HLH), raising the question of possible benefits that could be derived from targeted immunosuppression in severe COVID-19 patients. We reviewed the literature regarding the diagnosis and features of HLH, particularly secondary HLH, and aimed to identify gaps in the literature to truly clarify the existence of a COVID-19 associated HLH. Diagnostic criteria such as HScore or HLH-2004 may have suboptimal performance in identifying COVID-19 HLH-like presentations, and criteria such as soluble CD163, NK cell activity, or other novel biomarkers may be more useful in identifying this entity.


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