Homozygous TNNI3 frameshift variant in a consanguineous family with lethal infantile dilated cardiomyopathy.

BACKGROUND: Dilated cardiomyopathy (DCM) is characterized by dilatation of the left ventricle, systolic dysfunction, and normal or reduced thickness of the left ventricular wall. It is a leading cause of heart failure and cardiac death at a young age. Cases with neonatal onset DCM were correlated with severe clinical presentation and poor prognosis. A monogenic molecular etiology accounts for nearly half of cases. FAMILY DESCRIPTION: Here, we report a family with three deceased offspring at the age of 1 year old. The autopsy of the first deceased infant revealed a DCM. The second infant presented a DCM phenotype with a severely reduced Left Ventricular Ejection Fraction (LVEF) of 10%. Similarly, the third infant showed a severe DCM phenotype with LVEF of 30% as well, in addition to eccentric mitral insufficiency. RESULTS: Exome sequencing was performed for the trio (the second deceased infant and her parents). Data analysis following the autosomal dominant and recessive patterns of inheritance was carried out along with a mitochondrial pathways-based analysis. We identified a homozygous frameshift variant in the TNNI3 gene (c.204delG; p.(Arg69AlafsTer8)). This variant has been recently reported in the ClinVar database in association with cardiac phenotypes as pathogenic or likely pathogenic and classified as pathogenic according to ACMG. CONCLUSION: Genetic counseling was provided for the family and a prenatal diagnosis of choronic villus was proposed in the absence of pre-implantation genetic diagnosis possibilities. Our study expands the case series of early-onset DCM patients with a protein-truncating variant in the TNNI3 gene by reporting three affected infant siblings.

Catalyzing precision: unraveling the diagnostic conundrum of tunisian familial hypophosphatasia case through integrative clinical and molecular approaches.

Familial Hypophosphatasia presents a complex diagnostic challenge due to its wide-ranging clinical manifestations and genetic heterogeneity. This study aims to elucidate the molecular underpinnings of familial Hypophosphatasia within a Tunisian family harboring a rare c.896 T > C mutation in the ALPL gene, offering insights into genotype-phenotype correlations and potential therapeutic avenues. The study employs a comprehensive approach, integrating biochemical examination, genetic analysis, structural modeling, and functional insights to unravel the impact of this rare mutation. Genetic investigation revealed the presence of the p.Leu299Pro mutation within the ALPL gene in affected family members. This mutation is strategically positioned in proximity to both the catalytic site and the metal-binding domain, suggesting potential functional consequences. Homology modeling techniques were employed to predict the 3D structure of TNSALP, providing insights into the structural context of the mutation. Our findings suggest that the mutation may induce conformational changes in the vicinity of the catalytic site and metal-binding domain, potentially affecting substrate recognition and catalytic efficiency. Molecular dynamics simulations were instrumental in elucidating the dynamic behavior of the tissue-nonspecific alkaline phosphatase isozyme (TNSALP) in the presence of the p.Leu299Pro mutation. The simulations indicated alterations in structural flexibility near the mutation site, with potential ramifications for the enzyme's overall stability and function. These dynamic changes may influence the catalytic efficiency of TNSALP, shedding light on the molecular underpinnings of the observed clinical manifestations within the Tunisian family. The clinical presentation of affected individuals highlighted significant phenotypic heterogeneity, underscoring the complex genotype-phenotype correlations in familial Hypophosphatasia. Variability in age of onset, severity of symptoms, and radiographic features was observed, emphasizing the need for a nuanced understanding of the clinical spectrum associated with the p.Leu299Pro mutation. This study advances our understanding of familial Hypophosphatasia by delineating the molecular consequences of the p.Leu299Pro mutation in the ALPL gene. By integrating genetic, structural, and clinical analyses, we provide insights into disease pathogenesis and lay the groundwork for personalized therapeutic strategies tailored to specific genetic profiles. Our findings underscore the importance of comprehensive genetic and clinical evaluation in guiding precision medicine approaches for familial Hypophosphatasia.

Retrospective Analysis of Clinical Characteristics and Disease Outcomes in Children and Adolescents Hospitalized Due to COVID-19 Infection in Tunisia.

Due to low susceptibility of coronavirus disease of 2019 (COVID-19) in children, limited studies are available regarding COVID-19 in the pediatric population in Tunisia. The current study evaluated the incidence, clinical characteristics, and outcomes of severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) infection among children hospitalized at Béchir Hamza Children's Hospital. A retrospective cohort analysis was conducted using the hospital database between March 2020 and February 2022 with children aged ≤15 years with SARS-CoV-2 infection (confirmed by RT-PCR). A total of 327 COVID-19 hospitalized patients with a mean age of 3.3 years were included; the majority were male. Neurological disease (20%) was the most common comorbidity, while fever (95.3%) followed by cough (43.7%) and dyspnea (39.6%) were the most frequent symptoms reported. Severe disease with oxygen requirement occurred in 30% of the patients; 13% were admitted in the Intensive Care Unit. The overall incidence rate of COVID-19 hospitalization (in Tunis governorates) was 77.02 per 100,000 while the inpatient case fatality rate was 5% in the study population. The most prevalent circulating variant during our study period was Delta (48.8%), followed by Omicron (26%). More than 45% of the study population were <6 months and one-fourth (n = 25, 26.5%) had at least one comorbidity. Thus, the study findings highlight the high disease burden of COVID-19 in infants.

A gain-of-function mutation in zinc cluster transcription factor Rob1 drives Candida albicans adaptive growth in the cystic fibrosis lung environment.

Candida albicans chronically colonizes the respiratory tract of patients with Cystic Fibrosis (CF). It competes with CF-associated pathogens (e.g. Pseudomonas aeruginosa) and contributes to disease severity. We hypothesize that C. albicans undergoes specific adaptation mechanisms that explain its persistence in the CF lung environment. To identify the underlying genetic and phenotypic determinants, we serially recovered 146 C. albicans clinical isolates over a period of 30 months from the sputum of 25 antifungal-naive CF patients. Multilocus sequence typing analyses revealed that most patients were individually colonized with genetically close strains, facilitating comparative analyses between serial isolates. We strikingly observed differential ability to filament and form monospecies and dual-species biofilms with P. aeruginosa among 18 serial isolates sharing the same diploid sequence type, recovered within one year from a pediatric patient. Whole genome sequencing revealed that their genomes were highly heterozygous and similar to each other, displaying a highly clonal subpopulation structure. Data mining identified 34 non-synonymous heterozygous SNPs in 19 open reading frames differentiating the hyperfilamentous and strong biofilm-former strains from the remaining isolates. Among these, we detected a glycine-to-glutamate substitution at position 299 (G299E) in the deduced amino acid sequence of the zinc cluster transcription factor ROB1 (ROB1G299E), encoding a major regulator of filamentous growth and biofilm formation. Introduction of the G299E heterozygous mutation in a co-isolated weak biofilm-former CF strain was sufficient to confer hyperfilamentous growth, increased expression of hyphal-specific genes, increased monospecies biofilm formation and increased survival in dual-species biofilms formed with P. aeruginosa, indicating that ROB1G299E is a gain-of-function mutation. Disruption of ROB1 in a hyperfilamentous isolate carrying the ROB1G299E allele abolished hyperfilamentation and biofilm formation. Our study links a single heterozygous mutation to the ability of C. albicans to better survive during the interaction with other CF-associated microbes and illuminates how adaptive traits emerge in microbial pathogens to persistently colonize and/or infect the CF-patient airways.

Impact of Music Therapy on Quality of Life in Children with Cancer.

BACKGROUND: Music therapy (MT) is a non-pharmacological treatment increasingly used to reduce stress and anxiety in hospitalized children affected by cancers. The aim of this study was to evaluate the impact of MT on quality of life in children with cancer and determine its effect on cardiorespiratory rates. METHODS: We conducted a quasi-experimental study between 1 April and 31 August 2021 at Bechir Hamza children's Hospital in Tunis, including children treated for cancer. The child or parent completed the PedsQL Module Cancer French version 3.0 questionnaires before and after four weekly music therapy sessions. The child's respiratory and heart rates were measured before and after each session. RESULTS: We included 20 children whose mean age was 7 ± 4.5 years. The median value of the total questionnaire score increased from 57 [46; 70] to 72 [67; 85] (p < 10-3) noting a significant reduction in pain (p = 0.02), nausea (p = 0.009), and anxiety related to medical procedures (p = 0.009) and worry about the future (p = 0.005). We highlighted a significant decrease in respiratory and heart rate after MT (p < 0.05). CONCLUSIONS: MT has positive impact on quality of life in children with cancer and reduces stress by lowering their cardiorespiratory rates.

[Chemotherapy-induced febrile neutropenia in a Tunisian Department of Pediatric Oncology]. / Neutropénie fébrile chimio-induite dans une unité d'oncologie pédiatrique tunisienne.

Chemotherapy-induced neutropenia (FN) is the most common infectious complication in pediatric oncology. To our knowledge, no pediatric research has been published in Tunisia. The purpose of our study was to describe the features of FN among Tunisian children and to investigate factors correlated with FN. We conducted a prospective study of children with chemotherapy-induced FN at the Department of Pediatric Medicine A of the Tunis Children´s Hospital from July 2019 to December 2019. We recorded 50 episodes of FN in 32 patients whose mean age was 5.3 years (3 months-16 years). We included 26 patients with solid tumors (81%) and six patients with hemopathies (18.7%). The mean time between last treatment and fever onset was 10.67 days. Bacteriological investigation was contributory in 18% of cases and mainly showed gram positive cocci. Therapeutic protocol including 1st line empirical antibiotic therapy (3rd generation cephalosporin with aminoglycoside) was effective in 62% of cases. Mortality rate of patients with FN was 2%. The statistical study did not reveal any factor of correlation with late-onset neutropenia. In conclusion, our results are consistent with literature data on bacteriological documentation and mortality. Our 1st line treatment option based on 3rd generation cephalosporin associated with aminoglycoside was effective in 2/3 of the cases. In the future, oral antibiotics may be considered in patients at low risk for infection.

Pediatric Noncerebral Thromboembolism: Etiological Assessment and Outcome.

OBJECTIVE: To report clinical presentation and etiologic investigation findings during pediatric noncerebral thromboembolism. METHODS: Retrospective study of cases of vascular non cerebral thromboses admitted in Medicine infantile A Department of the Children's Hospital of Tunis over 08 years. RESULTS: We confirmed 14 cases of non cerebral vascular thromboses. So that these accidents constitute 0,26 ‰ of the overall etiologies of hospitalizations in the Department. The mean age of our patients was 56±41 months [25 days-12 1/2 years]. The sex ratio was 1.8. The vascular incident was venous in 2/3 of cases. The clinical presentation was mainly painful swelling in four cases, abrupt dyspnea and hematemesis in three cases each and the incident was locally asymptomatic in four cases. Thromboses locations included deep vein thrombosis of limbs (n=6), vena cava thrombosis (n=1), portal thrombosis (n=4) and pulmonary embolism (n=3). The promoting factors identified were: tumors in seven cases, thrombophilias and catheterization in four cases each, trauma, surgery and Behçet disease in one case each. Eleven patients received anticoagulant treatment including unfractioned heparin in three cases and low molecular weight heparin in the other cases. No one died while four patients developed sequelae. CONCLUSION: Vascular thromboses are rare in children. They are mostly venous and diagnosed in ill children especially those having central venous catheters. Outcome of pediatric thromboembolism depends on efficient anticoagulation therapy which is well tolerated by children.

Genetic characterisation of Staphylococcus aureus isolated from milk and nasal samples of healthy cows in Tunisia: First report of ST97-t267-agrI-SCCmecV MRSA of bovine origin in Tunisia.

OBJECTIVES: This study aimed to screen for and characterise methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA) in nasal swabs and milk from healthy cows from different regions in Tunisia. METHODS: A total of 141 Staphylococcus spp. isolates were recovered from milk and nasal samples of cows. S. aureus isolates were further characterised by determining their antimicrobial susceptibilities, genes encoding antimicrobial resistance and virulence factors, biofilm production, agr type and PFGE. spa and SCCmec typing and MLST were also performed for the MRSA isolate. RESULTS: Twenty-seven isolates (19.1%) were identified as S. aureus, of which 26 were MSSA and 1 was MRSA. The MSSA isolates were resistant to penicillin (73.1%), fusidic acid (61.5%), clindamycin (34.6%) and erythromycin (34.6%). The MRSA isolate, from a milk sample, was resistant to cefoxitin, penicillin, fusidic acid, amikacin and clindamycin. Twenty-five isolates (92.6%) had at least one enterotoxin gene. Only four isolates (14.8%) were positive for the tsst-1 gene. Genes encoding the exfoliative toxins D and A were detected in 9 (33.3%) and 6 (22.2%) isolates, respectively. The single MRSA isolate and 22 MSSA isolates were biofilm-producers on Congo red agar plates. Twelve pulsotypes were identified amongst 25 MSSA isolates revealing the clonal diversity of these isolates; however, one MSSA isolate was identified as CC398. The MRSA isolate was PVL-negative and was typed as ST97-t267-agrI-SCCmecV. CONCLUSION: Contamination of milk with S. aureus, especially enterotoxin- and TSST-1-positive strains, poses a potential public-health threat. This is the first report of MRSA of bovine origin in Tunisia.

Molecular diagnosis of bacterial meningitis by multiplex real time PCR in Tunisian children.

INTRODUCTION: Bacterial meningitis is a medical emergency requiring a fast and reliable diagnosis. Molecular methods such as real-time PCR (rt-PCR) offer an attractive alternative. Thus, this study aims to establish multiplex rt-PCRs detecting N. meningitidis, S. pneumoniae and H. influenzae b from cerebrospinal fluid in Tunisian children beyond neonatal age. METHODOLOGY: Using bioinformatic tools and experimentation, we validated the specificity and optimal criteria of PCRs for primers and probes of plyA (S. pneumoniae), ctrA and sodC (N. meningitidis) and bexA genes (H. influenzae b). We performed one multiplex RT-PCR for detection of S. pneumoniae and N. meningitidis targeting plyA and ctrA, sodC genes respectively, simultaneously with a singleplex RT-PCR for H. influenzae b. The sensitivity and specificity of our methods were assessed. Then, we tested our methods for 122 CSF samples collected from suspected meningitis cases between 2014 and 2016 in Bechir Hamza Children's Hospital of Tunis. RESULTS: Our results have shown the sensitivity of the designed PCRs was up to 10-4 DNA dilution and the specificity was 100%. PCR evaluation has shown 51 positive samples: 38 of pneumococcal cases, 12 meningococcal cases, 1 case of H. influenzae b with 8.57% and 50% of supplementary positive cases rates respectively. CONCLUSIONS: Our assay proved to be very sensitive, specific and rapid for bacterial meningitis diagnosis. In the recent context of Hib vaccination, the possibility of detecting S. pneumoniae and N. meningitidis separately constitute an attractive opportunity. Nevertheless, simultaneous detection of Hib remains relevant in specific clinical context and for epidemiologic study.

Clonal spread of methicillin-resistant Staphylococcus aureus-t6065-CC5-SCCmecV-agrII in a Libyan hospital.

OBJECTIVES: The aim of this study was to characterize 32 MRSA isolates recovered from wound specimens of patients in a Hospital in Tripoli, Libya, during 2013. METHODS: MRSA isolates were characterized by determining their antibiotic susceptibilities, genes encoding antibiotic resistance and virulence factors, the SCCmec class, agr type, spa typing, PFGE and MLST. RESULTS: PFGE and MLST revealed that all isolates were clonal and belonged to the Clonal Complex 5 (CC5). They harboured the SCCmecV and the agrII and the spa type was t6065. The majority of isolates were resistant to cefoxitin (32, 100%), penicillin (32, 100%), ampicillin (32, 100%), enrofloxacin (32, 100%), ciprofloxacin (32, 100%), fusidic acid (32, 100%), gentamicin (32, 100%), kanamycin (32, 100%), trimethoprim (32, 100%), and erythromycin (30, 93.7%). The main genes encoding antibiotic resistance were: blaZ (31, 96.8%), ermC (30, 93.7%), aph(3')-III a (3, 9.4%), aac6-aph2 (32, 100%), InuA (3, 9.4%), tetM (3, 9.4%), tetL (3, 9.4%), dfrG (28, 87.5%), fusC (32, 100%). All isolates were PVL negative; however, exfoliative-encoding genes (eta: 25) and enterotxin genes (seb: 32, seo: 32, sei: 32, ser: 32, seu: 32, seg: 32, sej: 32, sed: 31, sen: 29, seh: 26, sec: 26, sea: 6, sek: 5), haemolysin (hla (32), hld (32), hlg (32)) and immune evasion cluster proteins (scn: 32, sak: 32) were relevant. CONCLUSION: To the best of our knowledge this is the first report of a specific clonal spread of a multi-drug resistant MRSA-CC5- SCCmecV in a Libyan Hospital.

A founder mutation underlies a severe form of phosphoglutamase 3 (PGM3) deficiency in Tunisian patients.

Phosphoglucomutase 3 (PGM3) protein catalyzes the conversion of N-acetyl-d-glucosamine-6-phosphate (GlcNAc-6-P) to N-acetyl-d-glucosamine-1-phosphate (GlcNAc-1-P), which is required for the synthesis of uridine diphosphate N-acetylglucosamine (UDP-GlcNAc) an important precursor for protein glycosylation. Mutations in PGM3 gene have been recently shown to underlie a new congenital disorder of glycosylation often associated to elevated IgE. Herein, we report twelve PGM3 deficient patients. They belong to three highly consanguineous families, originating from a rural district in the west central Tunisia. The patient's clinical phenotype is characterized by severe respiratory and cutaneous infections as well as developmental delay and severe mental retardation. Fourteen patients died in early infancy before diagnosis supporting the severity of the clinical phenotype. Laboratory findings revealed elevated IgE, CD4 lymphopenia and impaired T cell proliferation in most patients. Genetic analysis showed the presence, of a unique homozygous mutation (p.Glu340del) in PGM3 gene leading to reduced PGM3 abundance. Segregating analysis using fifteen polymorphic markers overlapping PGM3 gene showed that all patients inherited a common homozygous haplotype encompassing 10-Mb on chromosome 6. The founder mutational event was estimated to have occurred approximately 100 years ago. To date, (p.Glu340del) mutation represents the first founder mutation identified in PGM3 gene. These findings will facilitate the development of preventive approaches through genetic counselling and prenatal diagnosis in the affected families.

Prognostic factors in children with extracranial malignant germ cell tumors: a monocentric pediatric Tunisian study.

Background Extracranial Germ cell tumors (GCT) are a rare and a heterogeneous group of pediatric cancers but highly curable. Aim We aimed to review management, outcome and prognostic factors that influence overall survival (OS) in a pediatric Tunisian oncologic unit. Methods We retrospectively evaluated between January 1998 and December 2012, 33 patients affected by extracranial germ cell tumors and treated according to TGM95 protocol established by the SFOPin a pediatric Tunisian oncologic unit. Results Patients had a mean age of 57 months (ranges: 1 day-13 years). There were 19 girls and 14 boys. Primary sites included 12 sacrococcygeal, 11 ovarian, 6 testicular, 3retro peritoneal and 1 mediastinal site. After a mean follow up of 26.1 months (ranges: 0-96 months), OSat 2 years and 5 years were respectively 82% and 75%. Event-free survival were respectively 79% at 2 years and 74% at 5 years. Various prognostic factors have been studied according to Kaplan-Meier. Univariate analyses identified significant factors which influence strongly OS: the stage (p=0.04), the completeness of surgery (p<0.001) and the relapse (p = 0, 0001). A multivariate study showed that only the quality of resection and the clinical stage remained strong significant prognostic factors (p=0,021) for 5-year OS. Conclusion Disease stage, completeness of surgery and relapse have been established as the most powerful prognostic parameter in our analysis. The improvement of survival of patients affected by extracranial germ cell tumors in Tunisia is a real achievement mainly due to the success of salvage treatments.

A Founder Effect of c.257 + 2T > C Mutation in NCF2 Gene Underlies Severe Chronic Granulomatous Disease in Eleven Patients.

Chronic granulomatous disease (CGD) is the prototypic functional neutrophil disorder caused by genetic defects in one of the five genes encoding the superoxide-generating nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase subunits of phagocytes. Mutations causing the most prevalent form of CGD in western populations are located in the X-linked-CYBB gene. The four remaining autosomal recessive (AR) forms collectively account for one-third of CGD cases. We investigated the clinical and molecular features of eleven patients with CGD from 6 consanguineous families, originating from contiguous regions in the west of Tunisia. The patients' clinical phenotype is characterized by a high incidence of mycobacterial infections. Five out of the eleven patients died despite treatment arguing in favor of a severe clinical form of CGD. These findings correlated with the absence of functional p67phox protein as well as the absence of residual reactive oxygen intermediates (ROI) production. Genetic analysis showed the presence, in all patients, of a unique mutation (c.257 + 2T > C) in NCF2 gene predicted to affect RNA splicing. Segregating analysis using nine polymorphic markers overlapping the NCF2 gene revealed a common haplotype spanning 4.1 Mb. The founder event responsible for this mutation was estimated to have arisen approximately 175 years ago. These findings will facilitate the implementation of preventive approaches through genetic counseling in affected consanguineous families.

Molecular identification of Gd A- and Gd B- G6PD deficient variants by ARMS-PCR in a Tunisian population.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common enzymopathy. More than 200 mutations in the G6PD gene have been described. In Tunisia, the A-African and the B-Mediterranean mutations predominate the mutational spectrum. The purpose of this study was to apply the amplification refractory mutation system (ARMS-PCR) to the identification of Gd A+, Gd A- and Gd B- variants in a cohort of deficient individuals and to establish a phenotype/genotype association. 90 subjects were screened for enzymatic deficiency by spectrophotometric assay. The molecular analyses were performed in a group of 50 unrelated patients. Of the 54 altered chromosomes examined, 60% had the Gd A- mutation, 18% showed the Gd B- mutation and in 20% of cases, no mutations have been identified. The ARMS-PCR showed complete concordance with the endonuclease cleavage reference method and agreed perfectly with previous Tunisian studies where Gd A- and Gd B- were the most encountered. Also, similarities in spectrum mutations with North African and Mediterranean countries suggest gene migration from Africa to Europe through Spain. In conclusion, ARMS has been introduced in this study for common G6PD alleles identification in Tunisia. It gives some advantages compared to the traditional endonuclease digestion method since it is more convenient and timesaving and also offers the possibility to be applied in mass screening surveys.

Soft Tissue Myoepithelial Carcinoma in a Child: Case Report.

BACKGROUND: Myoepithelial carcinoma was only recently recognized to occur primarily in soft tissue. Only a small number has been reported in children. OBSERVATION: We report a rare case of myoepithelial carcinoma of the leg in a 4-month-old boy with a good response to chemotherapy initially. However, he presented secondarily during chemotherapy a local and metastatic progression. CONCLUSIONS: The rarity of the tumor and unusual age of discovery have prompted us to report this case. Our case suggests that this disease can have an aggressive behavior. This is why we advise a rapid and correct diagnosis followed by an aggressive treatment.

Co-occurrence of Takayasu's arteritis and tuberculosis: Report of a Tunisian pediatric case.

Few reports on co-occurrence of Takayasu's arteritis (TA) and tuberculosis (Tb) have been published in childhood. A 12-year-old girl presented with 4-month's history of a dry cough, persistent fever, marked weakness, and weight loss. Physical examination revealed impalpable peripheral pulses and unrecordable blood pressure (BP) on upper limbs. In lower limbs, peripheral pulses were normal and BP reached respectively 160/90 and 140/87 mmHg. Laboratory investigations showed an erythrocyte sedimentation rate at 140 mm in the 1(st) h and microcytic anemia (8.6 g/dl). Doppler ultrasound and computed tomography angiography revealed significant thickening of the aortic-arch and both common carotid arteries wall, with luminal narrowing of the right common carotid and its branches and severe stenosis of the left subclavian artery. Simultaneously, the diagnosis of active pulmonary Tb was achieved based on radiological data, positive Mantoux test and successful response to antitubercular drugs. During follow-up, corticostetroids and methotrexate were required to control TA relapses.

The extended clinical phenotype of 64 patients with dedicator of cytokinesis 8 deficiency.

BACKGROUND: Mutations in dedicator of cytokinesis 8 (DOCK8) cause a combined immunodeficiency (CID) also classified as autosomal recessive (AR) hyper-IgE syndrome (HIES). Recognizing patients with CID/HIES is of clinical importance because of the difference in prognosis and management. OBJECTIVES: We sought to define the clinical features that distinguish DOCK8 deficiency from other forms of HIES and CIDs, study the mutational spectrum of DOCK8 deficiency, and report on the frequency of specific clinical findings. METHODS: Eighty-two patients from 60 families with CID and the phenotype of AR-HIES with (64 patients) and without (18 patients) DOCK8 mutations were studied. Support vector machines were used to compare clinical data from 35 patients with DOCK8 deficiency with those from 10 patients with AR-HIES without a DOCK8 mutation and 64 patients with signal transducer and activator of transcription 3 (STAT3) mutations. RESULTS: DOCK8-deficient patients had median IgE levels of 5201 IU, high eosinophil levels of usually at least 800/µL (92% of patients), and low IgM levels (62%). About 20% of patients were lymphopenic, mainly because of low CD4(+) and CD8(+) T-cell counts. Fewer than half of the patients tested produced normal specific antibody responses to recall antigens. Bacterial (84%), viral (78%), and fungal (70%) infections were frequently observed. Skin abscesses (60%) and allergies (73%) were common clinical problems. In contrast to STAT3 deficiency, there were few pneumatoceles, bone fractures, and teething problems. Mortality was high (34%). A combination of 5 clinical features was helpful in distinguishing patients with DOCK8 mutations from those with STAT3 mutations. CONCLUSIONS: DOCK8 deficiency is likely in patients with severe viral infections, allergies, and/or low IgM levels who have a diagnosis of HIES plus hypereosinophilia and upper respiratory tract infections in the absence of parenchymal lung abnormalities, retained primary teeth, and minimal trauma fractures.

Hypomorphic homozygous mutations in phosphoglucomutase 3 (PGM3) impair immunity and increase serum IgE levels.

BACKGROUND: Recurrent bacterial and fungal infections, eczema, and increased serum IgE levels characterize patients with the hyper-IgE syndrome (HIES). Known genetic causes for HIES are mutations in signal transducer and activator of transcription 3 (STAT3) and dedicator of cytokinesis 8 (DOCK8), which are involved in signal transduction pathways. However, glycosylation defects have not been described in patients with HIES. One crucial enzyme in the glycosylation pathway is phosphoglucomutase 3 (PGM3), which catalyzes a key step in the synthesis of uridine diphosphate N-acetylglucosamine, which is required for the biosynthesis of N-glycans. OBJECTIVE: We sought to elucidate the genetic cause in patients with HIES who do not carry mutations in STAT3 or DOCK8. METHODS: After establishing a linkage interval by means of SNPchip genotyping and homozygosity mapping in 2 families with HIES from Tunisia, mutational analysis was performed with selector-based, high-throughput sequencing. Protein expression was analyzed by means of Western blotting, and glycosylation was profiled by using mass spectrometry. RESULTS: Mutational analysis of candidate genes in an 11.9-Mb linkage region on chromosome 6 shared by 2 multiplex families identified 2 homozygous mutations in PGM3 that segregated with disease status and followed recessive inheritance. The mutations predict amino acid changes in PGM3 (p.Glu340del and p.Leu83Ser). A third homozygous mutation (p.Asp502Tyr) and the p.Leu83Ser variant were identified in 2 other affected families, respectively. These hypomorphic mutations have an effect on the biosynthetic reactions involving uridine diphosphate N-acetylglucosamine. Glycomic analysis revealed an aberrant glycosylation pattern in leukocytes demonstrated by a reduced level of tri-antennary and tetra-antennary N-glycans. T-cell proliferation and differentiation were impaired in patients. Most patients had developmental delay, and many had psychomotor retardation. CONCLUSION: Impairment of PGM3 function leads to a novel primary (inborn) error of development and immunity because biallelic hypomorphic mutations are associated with impaired glycosylation and a hyper-IgE-like phenotype.

Clinical, immunological and genetic findings of a large tunisian series of major histocompatibility complex class II deficiency patients.

INTRODUCTION: Major histocompatibility complex class II (MHC-II) expression deficiency is a combined primary immunodeficiency leading to the impairment of the cellular and humoral immune responses. A majority of affected patients belong to consanguineous families particularly from the Maghreb, where a founder effect for a highly frequent mutation (named c.338-25_338del26) in the RFXANK gene was reported. Herein, we report the largest single Maghrebian country series of MHC-II deficient patients. PATIENTS AND METHODS: In Tunisia, among 551 PIDs diagnosed from 1993 to 2011, 54 had an MHC-II deficiency. The clinical features and immunological investigations were retrospectively analyzed in 34 children of them belonging to 28 kindred. The genetic study included the c.338-25_338del26 screening by the amplification of the affected region using polymerase chain reaction (PCR) followed by direct sequencing. RESULTS: Consanguinity was present in 22 out of 28 families. Mean age at the first infection was 6.1 months. Chronic diarrhea with failure to thrive and pulmonary infections were the most common manifestations occurring in 26 and 28 patients respectively. The most specific laboratory findings were the defect of MHC-II (HLA-DR) expression in all patients. The c.338-25_338del26 mutation was identified in 25 of them. CONCLUSION: In Maghrebian settings, pediatricians should definitely consider this diagnosis in the presence of an early onset of severe and recurrent infections of the respiratory and intestinal tracts, particularly protracted diarrhea with a failure to thrive. The founder effect for the c.338-25_338del26 mutation in the RFXANK gene is also confirmed, facilitating prenatal diagnosis as a preventive approach in the Tunisian affected families with severe forms, particularly in the context of limited access to bone marrow transplantation.