Multiplex Minisequencing of the HBB Gene: A Rapid Strategy to Confirm the Most Frequent ß-Thalassemia Mutations in the Tunisian Population.

The ß hemoglobinopathies [ß-thalassemia (ß-thal) and structural hemoglobin (Hb) variants such as Hb S (HBB: c.20A > T) and Hb E (HBB: c.79G > A)] are among the most common inherited diseases worldwide. In Tunisia, due to the high prevalence of consanguineous marriages, the recurrent risk of this disease is high. The average prevalence of hemoglobinopathies is 4.48%, reaching 12.50% in some focus regions. The molecular investigations on thalassemia contributed to establishing the spectrum of mutations in the Tunisian population. The total number of HBB gene mutations identified was 24. The two most frequent mutations, codon 39 (C > T) (HBB: c.118C > T) and IVS-I-110 (G > A) (HBB: c.93-21G > A) accounted for 70.0% of the total encountered ß-thal cases. These two mutations together with IVS-I-2 (T > G) (HBB: c.92 + 2T > G) and the Hb S variant account for more than 90.0% of all HBB genetic variants in Tunisia. Thus, developing rapid, inexpensive and reliable mutation-specific molecular diagnostic assays targeting our Tunisian populations is our aim to facilitate routine detection of hemoglobinopathies. In this report, we describe the successful application of the multiplex minisequencing assay as an alternative strategy for genetic diagnosis of HBB gene disorders in Tunisia.

Clinical and radiological findings of posterior reversible encephalopathy syndrome in children: About 16 children hospitalized in the pediatric department of a Tunisian tertiary care hospital.

BACKGROUND: Posterior reversible encephalopathy syndrome (PRES) is a clinico-radiological entity most frequently described in young- or middle-aged adults with a rare occurrence among children. AIM: To determine the clinical, radiological features and outcome of PRES in children admitted to a Tunisian tertiary care pediatric department. METHODS: we retrospectively reviewed records of all children under 18 years old diagnosed with PRES and admitted to the PICU of the Pediatric department of Sahloul University Hospital from January 2000 to August 2021. RESULTS: Sixteen patients were enrolled in this study. The mean age of the study population at PRES onset was 10 years (range: 4-14 years) and the male female ratio was 3. The most frequent neurological signs were seizures (n = 16 cases), headache (n = 8 cases), and impaired level of consciousness (7 cases). Visual disturbances were found in one patient. Arterial hypertension was the most underlying cause (16 cases). Brain MRI showed vasogenic edema, mostly localized in the parietal (13 cases) and occipital (11 cases) lobes. Moreover, cytotoxic edema (2 cases), pathologic contrast enhancement (1 case), and hemorrhage (3 cases) were isolated on MRI. The outcome after specific management was favorable after the first onset in 13 cases and death occurred in 3 patients. Relapses were observed in 4 patients. CONCLUSION: Clinical features presented by children with PRES are variable and non-specific. MRI typically shows reversible posterior cerebral edema. However, in some cases, atypical neuro-imaging findings, such as cytotoxic edema infarction, hemorrhage and contrast enhancement can be observed.

Turner syndrome: results of the first Tunisian study group on Turner syndrome (TuSGOT).

OBJECTIVES: Early diagnosis in Turner syndrome is desirable to optimize growth and puberty and yet, it is often made late. Here, we aim to identify age at diagnosis, clinical features at presentation and potential strategies to improve the care of TS girls. METHODS: Retrospective study, including patients from 14 care centers across Tunisia including neonatal and pediatric care units, adult endocrinology and genetics departments. RESULTS: We identified 175 patients with TS, karyotype showing 45, xmonosomy in 83(47.4 %) with mosaicism in 37(20 %). Mean ± SD, median (range) age at diagnosis available in 173 patients was 13 ± 9.2,12 (birth-48) years. The diagnosis was antenatal in 4(2.3 %), from birth-2 years in 14 (8 %)with lymphoedema (8)and dysmorphic features (9),2-12 years in 53 (35.5 %) including 35 with short stature, 13-18 years in 43(28.8 %) with short stature(28) and delayed puberty(14) and 35(23.5 %) after 18 years, related to ovarian insufficiency (20) and short stature (11). The associated malformations were cardiac in 14 (12.8 %), renal in 22 (19.6 %). A total of 56 girls (32 %) had proven gonadal dysgenesis and 13 (7 %) had otological problems. Parental height was available in 71 girls (40 %) of whom 59 were below the lower end of parental target range (LTR) (83 %). CONCLUSIONS: This first Tunisian multicenter study, the first African of its kind, reveals that more than half of Turner syndrome cases are diagnosed after the age of 12 years. Subsequently, national strategies for an earlier TS diagnosis are needed such as measuring and plotting parental heights as well as introducing a systematic height screening at 5 years in Tunisia with a view to carrying out a re-audit in five years' time.

[Coronary artery aneurysm in Kawasaki disease and its risk factors : a retrospective study about 65 Tunisian children]. / Les complications coronaires de la maladie de Kawasaki et ses facteurs de risque : à propos de 65 cas d'enfants tunisien.

INTRODUCTION: Kawasaki syndrome (KS) is a systemic vasculitis of unknown etiology that affects medium and small blood vessels. The aim of our study is to analyze coronary artery lesions in children with KS and their risk factors. MATERIAL AND METHODS: All children under the age of 15 years-old presenting KS and admitted in the pediatric department of three university hospital (Sahloul hospital, and Farhat Hached hospital of Sousse, Ibn El Jazzar hospital of Kairoun) from January 2000 to December 2018 were included. RESULTS: Sixty-five patients were included in our study. The mean age at diagnosis was of 29.9 months [2-120 months] and the sex ratio was of 1.7. Echocardiography was performed in all patients. It showed coronary dilation in 37% of patients with coronary artery diameter of 4.2 mm on average [3.2-7mm]. The coronary aneurysm was small in 19 cases and medium in 5 cases. No giant aneurysm has been identified. In univariate analysis, the predictors of coronary artery lesions were male sex, atypical form, fever duration more than 10 days, hepatic cytolysis, thrombocytosis and anemia. In multivariate analysis, only the last four parameters were the predictive factors of the coronary artery involvement. CONCLUSION: Several risk factors can be used to determine which children are predisposed to develop coronary dilations. In case of patient with risk factors, intravenous immunoglobulins should be initiated early to avoid these serious complications.

Acute disseminated encephalomyelitis: A retrospective study of 20 children in a pediatrics department in Tunisia.

BACKGROUND: Acute disseminated encephalomyelitis (ADEM) is an inflammatory demyelinating disorder of the central nervous system. Little information is available about the clinical and neuroradiological profile or the follow-up of this disease in Tunisian children. AIM: To determine the clinical, laboratory, and radiological features and the outcome of ADEM in children admitted to the pediatrics department of a university hospital in Tunisia. METHODS: All children ≤ 18 years old presenting with ADEM and admitted to the tertiary referral center for pediatrics at Sahloul University Hospital from January 2000 to December 2020 were included in the study. The diagnosis of ADEM was confirmed according to the international pediatric multiple sclerosis study group criteria. RESULTS: A total of 20 patients (13 girls and 7 boys) fulfilled the diagnostic criteria for ADEM. The mean age at diagnosis was 5.6 years. The clinical presentation included polyfocal neurological signs such as cranial hypertension (45%), seizures (35%), and motor weaknesses (55%). Pyramidal tract signs and cranial nerve palsies were noted in 55% of cases. Brain magnetic resonance imaging showed particular features, namely, a relapsing tumor-like form in one case, and optic neuritis and demyelinating lesions of the white matter in the brain and the spinal cord with gadolinium cerebral ring-like enhancement in another case. The treatment consisted of intravenous immunoglobulin in 16 cases (80%) and corticosteroid in 19 cases (95%). Plasmapheresis was used for one patient. Complete recovery was observed in 12 patients (60%); 19 patients (95%) had a monophasic course of the disease while only one patient developed multiphasic ADEM. CONCLUSIONS: ADEM remains a difficult diagnosis in children. Nevertheless, after prompt diagnosis and adequate treatment, most children with ADEM have a favorable outcome with restitutio ad integrum.

Childhood sclerosing cholangitis associations in a Tunisian tertiary care hospital: a many-faceted disease.

Tfifha M, Kamoun T, Mama N, Mestiri S, Hassayoun S, Zouari N, Jemni H, Abroug S. Childhood sclerosing cholangitis associations in a Tunisian tertiary care hospital: a many-faceted disease. Turk J Pediatr 2019; 61: 905-914. Sclerosing cholangitis (SC) is a liver disorder affecting children and adults, causing chronic cholestasis and secondary biliary cirrhosis. The purpose of this study was to present different associated diseases to SC in a Tunisian tertiary care hospital. Six patients were identified with SC associated with other diseases, four males and two females. The first symptom was liver enlargement in all cases with abnormal liver biochemistry. A moderate increase in AST and ALT levels was registered in all cases with moderate cholestasis in 4 patients. Three of them presented an auto-immune condition. Two patients were diagnosed with auto-immune hepatitis prior to SC and Crohn disease in only one patient. One developed linear IgA bullous dermatosis. Three patients were diagnosed with Multisystemic Langerhans Cell Histiocytosis (LCH). The primary site of LCH was the liver associated secondary to insipidus diabetes (one case), mastoiditis (two cases) and chest localization (one case). The outcome of those patients was variable with poor prognosis especially for SC secondary to LCH. No patient underwent liver transplantation. SC is a rare disorder with variable clinical presentations. To our knowledge, this is the first report of this condition in Tunisian and North African children. Diagnosis and treatment of SC and its associations remains a challenge, especially because there is still no effective medical therapy aimed at preventing disease progression. Pediatric liver transplantation is the only life-extending therapeutic alternative for patients with end-stage liver failure. Liver transplantation has not been performed on young children in our country.

Pseudotumoral acute cerebellitis associated with mumps infection in a child.

Pseudotumoral cerebellitis in childhood is an uncommon presentation of cerebellitis mimicking a brain tumor. It often follows an inflammatory or infectious event, particularly due to varicella virus. Patients could have a wide clinical spectrum on presentation. Some patients may be asymptomatic or present at most with mild cerebellar signs, whereas others may suffer severe forms with brainstem involvement and severe intracranial hypertension mimicking tumor warranting surgical intervention. Imaging techniques especially multimodal magnetic resonance imaging represent an interesting tool to differentiate between posterior fossa tumors and acute cerebellitis. We describe a case of pseudotumoral cerebellitis in a 6-year-old girl consequent to mumps infection and review the literature on this rare association.

Success of anti-CD20 monoclonal antibody treatment for severe autoimmune hemolytic anemia caused by warm-reactive immunoglobulin A, immunoglobulin G, and immunoglobulin M autoantibodies in a child: a case report.

BACKGROUND: Autoimmune hemolytic anemia is rare in children. First-line therapies for this disease consist of corticosteroids and intravenously administered immunoglobulin that are effective in most patients. However, a small proportion of cases (5 to 10%) is refractory to these therapies and may represent a medical emergency, especially when hemolysis is due to warm immunoglobulin M. Recently, reports of the use of rituximab in adult autoimmune diseases have shown promising results. In children, there are few studies on the use of rituximab in the treatment for autoimmune hemolytic anemia, especially on its long-term efficacy and adverse effects. CASE PRESENTATION: Here, we report the case of a 10-year-old Tunisian girl with refractory acute autoimmune hemolytic anemia caused by warm-reactive immunoglobulin A, immunoglobulin G, immunoglobulin M, and C3d autoantibodies. First-line treatments using corticosteroids and intravenously administered immunoglobulin were ineffective in controlling her severe disease. On the other hand, she was successfully treated with rituximab. In fact, her hemolytic anemia improved rapidly and no adverse effects were observed. CONCLUSIONS: The case that we report in this paper shows that rituximab could be an alternative therapeutic option in severe acute autoimmune hemolytic anemia with profound hemolysis refractory to conventional treatment. Moreover, it may preclude the use of plasmapheresis in such an urgent situation with a sustained remission.

Clinical and imaging features of malignant infantile osteopetrosis.

Tfifha M, Gaha M, Gamaoun W, Chemli J, Mabrouk S, Hassayoun S, Zouari N, Jemni H, Abroug S. Clinical and imaging features of malignant infantile osteopetrosis. Turk J Pediatr 2017; 59: 452-457. Human osteopetrosis is a rare genetic disorder caused by osteoclast failure. It encompasses a group of highly heterogeneous forms, ranged widely in severity. Patients with autosomal recessive osteopetrosis are the most severely affected osteopetrotic patients. Here we describe Tunisian children with severe phenotype. They are native from the same geographic region, born to consanguineous parents. Clinical features were cranio-facial dysmorphy, macrocephaly, hepatosplenomegaly, severe anemia and thrombocytopenia with precocious onset of neuronopathic complications, blindness and deafness. Retinal atrophy, reported in a minority of forms is highlighted. Skeletal radiographs revealed generalized increase in bone density and abnormal metaphyseal remodeling, and superimposed rickets resulting from the defect in osteoclasts to provide a normal Ca/P balance. We report an exceptional association with congenital hypothyroidism. Multi-organ failure due to sepsis is one the most severe complications observed. The issue was fatal without hematopoietic stem cell transplantation.

Ellis van Creveld syndrome in a Tunisian child revealed by an Eisenmenger syndrome.

Ellis-van Creveld syndrome (EvC) is an autosomal recessive inherited disease resulting from mutations in EVC1 or EVC2. Patients with this condition normally have chondrodysplasia, postaxial polydactyly, ectodermal dysplasia and congenital heart defects. We report the case of a 13-year-old Tunisian child who was admitted for cyanosis and acute heart failure. On clinical examination, he presented with typical features of EvC, cyanosis and dyspnea. EvC was confirmed by genetic tests, and echocardiography showed a partial atrioventricular canal defect with supra-systemic pulmonary artery pressure. The patient was treated; however, the evolution was fatal.

Mutation spectrum of primary hyperoxaluria type 1 in Tunisia: implication for diagnosis in North Africa.

BACKGROUND: Primary hyperoxaluria type 1 (PH1) is an autosomal recessive inherited metabolic disease, characterized by progressive kidney failure due to renal deposition of calcium oxalate. Mutations in the AGXT gene, encoding the liver-specific enzyme alanine glyoxylate aminotransferase, are responsible for the disease. We aimed to determine the mutational spectrum causing PH1 and to provide an accurate tool for diagnosis as well as for prenatal diagnosis in the affected families. METHODS: Direct sequencing was used to detect mutations in the AGXT gene in DNA samples from 13 patients belonging to 12 Tunisian families. RESULTS: Molecular analysis revealed five mutations causing PH1 in Tunisia. The mutations were identified along exons 1, 2, 4, 5 and 7. The most predominant mutations were the Maghrebian "p.I244T" and the Arabic "p.G190R". Furthermore, three other mutations characteristic of different ethnic groups were found in our study population. These results confirm the mutational heterogeneity related to PH1 in Tunisian population. All the mutations are in a homozygous state, reflecting the high impact of endogamy in our population. CONCLUSION: Mutation analysis through DNA sequencing can provide a useful first line investigation for PH1. This identification could provide an accurate tool for prenatal diagnosis, genetic counseling and screen for potential presymptomatic individuals.

Steroid 21-hydroxylase gene mutational spectrum in 50 Tunisian patients: characterization of three novel polymorphisms.

Congenital adrenal hyperplasia (CAH) is an autosomal recessive disease of steroid biosynthesis in humans. More than 90% of all CAH cases are caused by mutations of the 21-hydroxylase gene (CYP21A2), and approximately 75% of the defective CYP21A2 genes are generated through an intergenic recombination with the neighboring CYP21A1P pseudogene. In this study, the CYP21A2 gene was genotyped in 50 patients in Tunisia with the clinical diagnosis of 21-hydroxylase deficiency. CYP21A2 mutations were identified in 87% of the alleles. The most common point mutation in our population was the pseudogene specific variant p.Q318X (26%). Three novel single nucleotide polymorphism (SNP) loci were identified in the CYP21A2 gene which seems to be specific for the Tunisian population. The overall concordance between genotype and phenotype was 98%. With this study the molecular basis of CAH has been characterized, providing useful results for clinicians in terms of prediction of disease severity, genetic and prenatal counseling.