Loss of function of ENT3 drives histiocytosis and inflammation through TLR-MAPK signaling.

Histiocytoses are inflammatory myeloid neoplasms often driven by somatic activating mutations in mitogen-activated protein kinase (MAPK) cascade genes. H syndrome is an inflammatory genetic disorder caused by germ line loss-of-function mutations in SLC29A3, encoding the lysosomal equilibrative nucleoside transporter 3 (ENT3). Patients with H syndrome are predisposed to develop histiocytosis, yet the mechanism is unclear. Here, through phenotypic, molecular, and functional analysis of primary cells from a cohort of patients with H syndrome, we reveal the molecular pathway leading to histiocytosis and inflammation in this genetic disorder. We show that loss of function of ENT3 activates nucleoside-sensing toll-like receptors (TLR) and downstream MAPK signaling, inducing cytokine secretion and inflammation. Importantly, MEK inhibitor therapy led to resolution of histiocytosis and inflammation in a patient with H syndrome. These results demonstrate a yet-unrecognized link between a defect in a lysosomal transporter and pathological activation of MAPK signaling, establishing a novel pathway leading to histiocytosis and inflammation.

CLDN1 Arg81His founder variant causes ichthyosis, leukocyte vacuoles, alopecia, and sclerosing cholangitis (ILVASC) syndrome in Moroccan Jews.

Neonatal ichthyosis and sclerosing cholangitis syndrome (NISCH), also known as ichthyosis, leukocyte vacuoles, alopecia, and sclerosing cholangitis (ILVASC), is an extremely rare disease of autosomal recessive inheritance, resulting from loss of function of the tight junction protein claudin-1. Its clinical presentation is highly variable, and is characterized by liver and ectodermal involvement. Although most ILVASC cases described to date were attributed to homozygous truncating variants in CLDN1, a single missense variant CLDN1 p.Arg81His, associated with isolated skin ichthyosis phenotype, has been recently reported in a family of Moroccan Jewish descent. We now describe seven patients with ILVASC, originating from four non consanguineous families of North African Jewish ancestry (including one previously reported family), harboring CLDN1 p.Arg81His variant, and broaden the phenotypic spectrum attributed to this variant to include teeth, hair, and liver/bile duct involvement, characteristic of ILVASC. Furthermore, we provide additional evidence for pathogenicity of the CLDN1 p.Arg81His variant by transmission electron microscopy of the affected skin, revealing distorted tight junction architecture, and show through haplotype analysis in the vicinity of the CLDN1 gene, that this variant represents a founder variant in Jews of Moroccan descent with an estimated carrier frequency of 1:220.

Hypoparathyroidism-Retardation-Dysmorphism Syndrome due to a Variant in the Tubulin-Specific Chaperone E Gene as a Cause of Combined Immune Deficiency.

BACKGROUND: Hypoparathyroidism-retardation-dysmorphism (HRD) syndrome is a disease composed of hypoparathyroidism, growth retardation, severe developmental delay, and typical dysmorphic features caused by the tubulin-specific chaperone E gene variant. Many patients succumb in infancy to HRD due to overwhelming infections mainly caused by Pneumococcus spp. Knowledge related to the immune system in these patients is scarce. PURPOSE: To define the immune phenotype of a cohort of HRD patients including their cellular, humoral, and neutrophil functions. METHODS: The study included HRD patients followed at Soroka University Medical Center. Clinical and immunological data were obtained, including immunoglobulin concentrations, specific antibody titers, lymphocyte subpopulations, lymphocyte proliferation, and neutrophil functions. RESULTS: Nine patients (5 females and 4 males) were enrolled, aged 6 months to 15 years. All received amoxicillin prophylaxis as part of a routine established previously. Three patients had bacteremia with Klebsiella, Shigella spp., and Candida. Three patients had confirmed coronavirus disease 19 (COVID-19), and two of them died from this infection. All patients had normal blood counts. Patients showed high total IgA and IgE levels, low anti-pneumococcal antibodies in spite of a routine vaccination schedule, and reduced frequency of naive B cells with increased frequency of CD21lowCD27- B cells. All patients had abnormal T-cell population distributions, including reduced terminally differentiated effector memory CD8, inverted CD4/CD8 ratios, and impaired phytohemagglutinin (PHA)-induced lymphocyte proliferation. Neutrophil superoxide production and chemotaxis were normal in all patients tested. CONCLUSION: HRD is a combined immunodeficiency disease with syndromic features, manifesting in severe invasive bacterial and viral infections.

Early-life liver cirrhosis and variable clinical presentation in telomere disease.

AIM: Telomeres are DNA sequences of tandem TTAGGG repeats that protect chromosome ends from degradation and instability. Constitutional loss-of-function telomerase mutations result in rapid telomere shortening, premature senescence and cell death. Liver cirrhosis is rare and has only been reported in adults. We present five family members of Bedouin-Muslim origin, all of which carry the same mutation, and yet demonstrate an extremely variable phenotypical presentation, including liver cirrhosis during early childhood. METHODS: A multidisciplinary long-term follow-up of two healthy and three affected patients was analysed. The mutation (r.95G>C) was identified in all patients using Sanger sequencing. Telomere length samples were obtained and analysed. RESULTS: Clinical phenotypes were extremely variable, including age at first symptoms, organ involvement, disease severity and patient prognosis. The most prominent clinical phenotype is liver involvement, including end-stage liver disease early in life, which affects three members of the family. Affected patients had markedly shorter telomeres. CONCLUSION: We describe an unusual presentation of early liver failure in telomere disease patients. Little, if any, is known about the association between the genotype and phenotype among children with telomere disease and whether the mutation we have described (r.95G>C) is predisposed to early severe hepatic involvement.

Predictive Prenatal Diagnosis for Infantile-onset Inflammatory Bowel Disease Because of Interleukin-10 Signalling Defects.

OBJECTIVES: Advances in genetic technologies provide opportunities for patient care and ethical challenges. Clinical care of patients with rare Mendelian disorders is often at the forefront of those developments. Whereas in classical polygenic inflammatory bowel disease (IBD), the predictive value of genetic variants is very low, predictive prenatal genetic diagnosis can inform families at high risk of severe genetic disorders. Patients with IL-10 signalling defects because of pathogenic variants in IL10RA, Il10RB, and IL10 develop severe infantile onset inflammatory bowel disease that is completely penetrant and has a high morbidity and substantial mortality despite treatment. METHODS: We performed a survey among tertiary specialist paediatric centers of 10 countries on the utilization of predictive prenatal genetic diagnosis in IL-10 signalling defects. We retrospectively report prenatal genetics in a series of 8 families. RESULTS: International variation in legislation, guidelines, expert opinion, as well as cultural and religious background of families and clinicians results in variable utilization of preimplantation and prenatal genetic testing for IL-10 signalling defects. Eleven referrals for prenatal diagnosis for IL-10 signalling defects were identified across 4 countries. We report on 8 families who underwent prenatal preimplantation monogenic testing after in vitro fertilization (n = 2) and/or by amniocentesis/chorion villus sampling (n = 6). A genetic diagnosis was established in 1 foetus and excluded in 7 foetuses (all IL10RA variants). CONCLUSIONS: Prenatal genetic testing for IL10R-defects is feasible, yet the legal and ethical considerations are complex and controversial. In some countries, predictive genetics for IL-10-related signalling defects is entering clinical practice.

Glomerular involvement in children with H syndrome.

BACKGROUND: H syndrome is a multisystem inflammatory disease caused by mutations in the SLC29A3 gene (OMIM #602782). The protein product, hENT3, is a nucleoside transporter essential for DNA salvage synthesis. Clinical manifestations are hyperpigmentation, hypertrichosis, hepatosplenomegaly, hearing loss, heart anomalies, hypogonadism, short stature, skeletal deformities, and diabetes mellitus. Laboratory findings are consistent with inflammatory processes. Structural kidney anomalies have been described in 6% of patients. CASE REPORTS: Three family members with genetically diagnosed H syndrome (c.1279G>A, p.Gly427Ser). Two of them presented with hypoalbuminemia and nephrotic range proteinuria. Kidney ultrasound was normal. Kidney biopsy performed in one patient presenting with generalized peripheral pitting edema revealed membranous nephropathy. Different treatments including ACE inhibitors, corticosteroids, and immunomodulatory agents failed to improve the clinical outcome. CONCLUSIONS: Generalized peripheral pitting edema and glomerulopathy broaden the clinical spectrum of H syndrome. Periodic bloodwork and urinalysis are recommended.

Pituitary stalk interruption syndrome broadens the clinical spectrum of the TTC26 ciliopathy.

Ciliopathies are a heterogeneous group of disorders, related to abnormal ciliary function. Severe biliary ciliopathy, caused by bi-allelic mutations in TTC26, has been recently described in the context of a syndrome of polydactyly and severe neonatal cholestasis, with brain, kidney and heart involvement. Pituitary involvement has not been previously reported for patients with this condition. Pituitary stalk interruption syndrome (PSIS) is a congenital anomaly of the pituitary gland, diagnosed by characteristic MRI findings. We now describe four patients with TTC26 ciliopathy due to a homozygous c.695A>G p.Asn232Ser mutation and delineate PSIS as a novel clinical feature of this disorder, highlighting an important role of TTC26 in pituitary development.

Central venous catheter-associated bloodstream infections in children diagnosed with intestinal failure in Southern Israel.

OBJECTIVES: To study the clinical, epidemiological, and microbiological associations between intestinal failure (IF) and central line-associated infections (CLABSI) in patients with central vein catheters (CVCs) during 2005-2016. METHODS: We compared retrospectively CLABSI rates according to background disease, type of line access, pathogen distribution, and antibiotic susceptibilities. RESULTS: One hundred and fourteen children (64.1% < 4 years) were enrolled. Main diagnoses were persistent diarrhea (20, 17.5%), short bowel syndrome (13, 11.4%), continuous-TPN w/o diarrhea (11, 9.7%), very early-onset inflammatory bowel disease (VEO-IBD, 8, 7%), Hirschsprung's disease (3, 2.6%), non-oncologic hematologic conditions (13, 11.4%), and other diseases (46, 40.4%). 152.749 catheter days were recorded; 71.1% had Hickman's catheters. Two hundred and nine CLABSI episodes were recorded in 58 patients (82% with IF, 13.7 and 8.2/1000 catheter days in IF, and non-gastrointestinal conditions, P = 0.09). More CLABSI were recorded in continuous TPN vs. VEO-IBD or persistent diarrhea (38.8 vs.15.8 and 12.8/1000 catheter days, P < 0.004). Among patients with Hickman in jugular vein, highest CLBSI incidence was in continuous TPN, VEO-IBD, and persistent diarrhea (29.9, 15.84, and 12.49 episodes/1000 catheter days, respectively). CVCs were removed in 38.8% CLABSI. Two hundred and thirty-five pathogens were isolated (Enterobacteriaceae spp. in 39% of IF patients, mostly in persistent diarrhea and short bowel syndrome patients, 47.6% and 34.8%, respectively). Coagulase-negative Staphylococcus was the commonest pathogen in continuous TPN, VEO-IBD, and Hirschsprung's (71.4%, 55.6% and 46.1%, respectively). CONCLUSIONS: CLABSI rates in IF patients were among the highest reported. We reported a "hierarchy" in CLABSI incidence among patients with IF and showed that CLABSI incidence and etiology were different as function of background diseases and CVC insertion site.

Seasonality of birth affects paediatric coeliac disease.

AIM: This study investigated the seasonality of birth in children diagnosed with coeliac disease (CD) at a tertiary University hospital in Southern Israel. METHODS: This was a population-based retrospective time series analysis study from January 1988 to December 2014. There were 308 903 live births at Soroka University Medical Centre during the study period and 699 were diagnosed with CD. We combined three databases covering births, CD diagnoses and weather indices. The daily proportion of births that resulted in CD for the different four seasons and high seasons were compared to the weather indices on the day of birth using negative binomial regression. RESULTS: Statistically significant associations were found between the season of birth and the rate of CD, with autumn births being associated with a higher risk for the development of CD than births during the summer, with an incidence ratio of 1.22. The association was further increased when the defined summer and autumn high seasons were used, with an incidence ratio of 1.40. No association was found between CD and the mean temperature and global radiation. CONCLUSION: Coeliac disease was associated with birth during the autumn and the autumn high season posed an even more significant risk factor.

Urinary tract infection in young infants discharged from the emergency room with normal urinalysis.

AIM: We describe the clinical, microbiologic, therapeutic, and outcome characteristics of infants under three months of age with a positive urine culture reported after discharge from emergency department with normal urinalysis. METHODS: We enrolled all infants with a urine culture obtained during an emergency room visit during 2004-2012, discharged without antibiotic therapy and subsequently reported with a positive urine culture. RESULTS: Three hundred and ninety-three positive urine cultures were reported; 46/393 (11.7%, 42 in patients under two months of age) had positive urine cultures following normal urinalysis at first visit. Fifteen (33%) had positive urine cultures at second visit; 11/15 (73%) infants with second positive urine culture were under one month of age, eight were asymptomatic and seven had mild symptoms at second visit. Pathogens isolated in all 15 infants were identical between first and second visit. All 27 infants re-examined at second visit at the emergency room were hospitalised, completed sepsis work/up and received antibiotic treatment. None developed serious bacterial infections. CONCLUSION: We propose a new management approach for young infants with normal urinalysis and positive urine culture and suggest restricting the management option including hospitalisation, sepsis work/up and antibiotic treatment at second visit only to infants under one month of age.

Incidence of typically Severe Primary Immunodeficiency Diseases in Consanguineous and Non-consanguineous Populations.

PURPOSE: Primary immunodeficiency diseases are considered to be rare diseases; however, data on the exact birth incidences of these diseases are sparse. Southern Israel is inhabited by two major populations: a relatively non-consanguineous Jewish population and a highly consanguineous Muslim Bedouin population. We sought to calculate the incidences of typically severe primary immunodeficiency diseases and compare the incidences in these populations. METHODS: A retrospective analysis of all typically severe primary immunodeficiency diseases evaluated at a single center from January 1, 1996 to December 31, 2016. The amount of live births by population was the denominator for calculating the incidences by population. RESULTS: A total of 95 patients were included, 85 of Bedouin and 10 of Jewish ethnicities. There were 152,331 births in the Bedouin and 160,998 births in the Jewish populations. The total incidence of typically severe primary immunodeficiency diseases was higher in the Bedouin population than expected based on previous studies. The total incidences were 55.8/105 births in the Bedouin population compared with 6.2/105 births in the Jewish population (P < 0.001). The incidences of all combined immunodeficiency diseases, ataxia telangiectasia, and infantile IBD due to interleukin 10 receptor defects were all significantly higher in the Bedouin population (P < 0.001). The incidence of X-linked agammaglobulinemia was not significantly different between both populations (P = 0.11). CONCLUSIONS: Typically, severe primary immunodeficiency diseases are not rare diseases in a consanguineous population; these diseases are significantly more common in the Bedouin population. This finding is probably also applicable to other consanguineous populations, and in these populations, primary immunodeficiency diseases should not be regarded as rare diseases.

Neonatal ascites in autosomal recessive polycystic kidney disease (ARPKD).

BACKGROUND: Neonatal ascites is a rare entity, which is usually biliary, urinary, or chylous. Congenital hepatic fibrosis as part of the manifestations of autosomal recessive polycystic kidney disease (ARPKD) is usually a histological adjunct to the diagnosis of this mainly clinically renal entity in the neonatal period. Case-diagnosis: We describe a rare case of severe ascites in a newborn child complicating ARPKD, which was later confirmed by clinical, histological, and genetic studies. CONCLUSION: ARPKD should be considered in differential diagnosis of neonatal ascites.

X-linked C1GALT1C1 mutation causes atypical hemolytic uremic syndrome.

Hemolytic-uremic syndrome (HUS), mostly secondary to infectious diseases, is a common cause of acute kidney injury in children. It is characterized by progressive acute kidney failure due to severe thrombotic microangiopathy, associated with nonimmune, Coombs-negative hemolytic anemia and thrombocytopenia. HUS is caused mostly by Shiga toxin-producing E. Coli, and to a lesser extent by Streptococcus pneumonia. In Streptococcus pneumonia HUS (pHUS), bacterial neuraminidase A exposes masked O-glycan sugar residues on erythrocytes, known as the T antigen, triggering a complement cascade causing thrombotic microangiopathy. Atypical HUS (aHUS) is a life-threatening genetic form of the disease, whose molecular mechanism is only partly understood. Through genetic studies, we demonstrate a novel X-linked form of aHUS that is caused by a de-novo missense mutation in C1GALT1C1:c.266 C > T,p.(T89I), encoding a T-synthase chaperone essential for the proper formation and incorporation of the T antigen on erythrocytes. We demonstrate the presence of exposed T antigen on the surface of mutant erythrocytes, causing aHUS in a mechanism similar to that suggested in pHUS. Our findings suggest that both aHUS caused by mutated C1GALT1C1 and pHUS are mediated by the lectin-complement-pathway, not comprehensively studied in aHUS. We thus delineate a shared molecular basis of aHUS and pHUS, highlighting possible therapeutic opportunities.

Immune dysregulation in Glycogen Storage Disease 1b - a CyTOF approach.

Glycogen Storage Disease type 1b (GSD1b) is a rare disease manifesting as hypoglycemia, recurrent infections and neutropenia, resulting from deleterious mutations in the SLC37A4 gene encoding the glucose-6-phosphate transporter. The susceptibility to infections is thought to be attributed not only to the neutrophil defect, though extensive immunophenotyping characterization is currently missing. Here we apply a systems immunology approach utilizing Cytometry by Time Of Flight (CyTOF) to map the peripheral immune landscape of 6 GSD1b patients. When compared to control subjects, those with GSD1b had a significant reduction in anti-inflammatory macrophages, CD16+ macrophages, and Natural Killer cells. Additionally, there was a preference towards a central versus an effector memory phenotype in multiple T cell populations, which may suggest that these changes stem from an inability of activated immune cell populations to undergo the appropriate switch to glycolytic metabolism in the hypoglycemic conditions associated with GSD1b. Furthermore, we identified a global reduction of CD123, CD14, CCR4, CD24 and CD11b across several populations and a multi-cluster upregulation of CXCR3, hinting at a potential role of impaired immune cell trafficking in the context of GSD1b. Taken together, our data indicates that that the immune impairment observed in GSD1b patients extends far beyond neutropenia and encompasses innate and adaptive compartments, which may provide novel insights into the pathogenesis of this disorder.

Case Report: Extensive Facial Cutaneous Leishmaniasis in a Neonate.

Cutaneous leishmaniasis (CL) is a skin infection caused by various species of the Leishmania parasite and is spread by the bite of an infected female sandfly. In southern Israel, CL caused by Leishmania major is endemic. Cutaneous leishmaniasis is considered a self-limiting disease, characterized by progressive, long-lasting nodulo-ulcerative skin lesions, which usually resolve in several months to years, and leads to scarring, cosmetic disfigurement, and future stigmatization. Although CL is a common disease among children, reports of CL in children younger than 1 year are rare. We present a case of extensive facial CL in an infant whose initial lesions appeared only 25 days after birth. The patient was treated with intravenous liposomal amphotericin B. Two months later, marked improvement was seen, with complete resolution of the inflammation and atrophic scar formation. To our knowledge, this is the earliest age of CL published to date.

Hyper IgM in tricho-hepato-enteric syndrome due to TTC37 mutation.

Tricho-hepato-enteric syndrome (THES) (OMIM #222,470) is a rare autosomal recessive syndromic enteropathy whose primary manifestations are dysmorphism, intractable diarrhea, failure to thrive, hair abnormalities, liver disease, and immunodeficiency with low serum IgG concentrations. THES is caused by mutations of either Tetratricopeptide Repeat Domain 37 (TTC37) or Ski2 like RNA Helicase (SKIV2L), genes that encode two components of the human SKI complex. Here, we report a patient with a TTC37 homozygous mutation phenotypically typical for tricho-hepato-enteric syndrome in whom extremely elevated IgM with low IgG was present at the time of diagnosis. These manifestations were not previously described in THES patients and this raised our index of suspicion towards "atypical" hyper IgM syndrome. Although the pathogenesis of immunoglobulin production dysfunction in THES is still elusive, this disorder should be considered in the differential diagnosis in patients with elevated IgM and syndromic features.

Ocular manifestations of congenital insensitivity to pain: a long-term follow-up.

AIM: To describe ocular manifestations in children with congenital insensitivity to pain with and without anhidrosis (CIPA and CIP). METHODS: We reviewed records of eye examinations of 39 children diagnosed with CIPA or CIP. We collected clinical data, with particular attention to ocular surface findings. Corneal sensitivity was tested by presence of a blink reflex upon touching the cornea. Statistical analysis assessed differences in manifestations between the two conditions, and relationships among corneal sensitivity, presence of corneal opacities and visual acuity (VA). RESULTS: CIPA was diagnosed in 32 children and CIP in 7. The median follow-up periods were 50 months (CIPA group) and 94 months (CIP group). Corneal opacities were present in 23% of CIPA eyes and in 57% of CIP eyes. A blink reflex was positive in 52% of CIPA eyes and in 33% of CIP eyes. We recorded VA ≥20/25 in 36% of CIPA eyes, whereas all patients with CIP had VA ≤20/30. For the whole cohort, we found a negative correlation between a preserved blink reflex and the presence of corneal opacities, and a positive correlation between a preserved blink reflex and VA ≥20/25. CONCLUSION: Children with congenital insensitivity to pain are prone to develop corneal scarring. Patients with CIP tend to have more severe ocular surface disease than those with CIPA, probably due to more prevalent loss of corneal sensation. In both groups, a preserved blink reflex correlated with good vision. Affected children should have close follow-up to promptly treat ocular surface disease and prevent vision loss.

Hypoparathyroidism-retardation-dysmorphism syndrome-Clinical insights from a large longitudinal cohort in a single medical center.

Background: Hypoparathyroidism, retardation, and dysmorphism (HRD) Syndrome is a rare disease composed of hypoparathyroidism, retardation of both growth and development, and distinctive dysmorphic features. Here, we describe the long-term morbidity and mortality in a large cohort of HRD patients and suggest recommendations for follow up and treatment. Methods: Medical records of 63 HRD syndrome patients who were followed at Soroka Medical Center during 1989-2019 were reviewed retrospectively. Information regarding demographics, medical complications, laboratory findings, and imaging studies was collected. Results: The mortality rate was 52%. The main causes of death were infectious diseases including pneumonia, septic shock, and meningitis. Multiple comorbidities were found including brain anomalies in 90% of examined patients (basal ganglia calcifications, tightening of corpus callosum, Chiari malformation, hydrocephalous, and brain atrophy), seizures in 62%, nephrocalcinosis and/or nephrolithiasis in 47%, multiple eye anomalies were recorded in 40%, bowel obstructions in 9.5%, and variable expression of both conductive and senso-neural hearing loss was documented in 9.5%. Conclusion: HRD is a severe multisystem disease. Active surveillance is indicated to prevent and treat complications associated with this rare syndrome.

A novel zeta-associated protein 70 homozygous mutation causing combined immunodeficiency presenting as neonatal autoimmune hemolytic anemia.

Biallelic mutations in the zeta-associated protein 70 (ZAP70) gene cause combined immunodeficiency (CID). Neonatal screening for severe CID in Israel is implemented since 2015. We report on clinical, flow cytometry, and genetic data of an unusual ZAP70 deficiency patient. A 10-week-old Bedouin female presented with severe autoimmune hemolytic anemia. Cytomegalovirus (CMV) negative packed cell therapy was given without improvement; indexes of hemolysis worsened. At this time, thrombocytopenia was noted. The patient was treated with single dose of 1 g/kg intravenous immunoglobulin with rapid resolution of hemolysis. Serum immunoglobulin concentrations were normal; flow cytometry revealed severe CD8 lymphocytopenia. Lymphocyte proliferation test demonstrated reduced response to concanavalin A and phytohemagglutinin. Gated T cells were negative for intracellular ZAP70. A genetic analysis revealed a missense homozygous c.1388C > T (p.A463V) mutation, confirming the diagnosis of ZAP70 deficiency. She later on developed urinary tract infection due to ESBL producing E. coli treated with amikacin and severe CMV infection that partially responded to ganciclovir therapy and at 7 months of age, she successfully underwent allogeneic hematopoietic stem cell transplantation. Neonatal screening by T cell receptor excision circles (TRECs) for SCID was normal, yet very low TRECs were recorded at the time of CID diagnosis. Normal neonatal screening for SCID does not rule out the diagnosis of CID due to ZAP70 deficiency. This type of CID can present with autoimmunity as the sole initial manifestation of the disease.