Current phenotypic and genetic spectrum of syndromic deafness in Tunisia: paving the way for precision auditory health.

Hearing impairment (HI) is a prevalent neurosensory condition globally, impacting 5% of the population, with over 50% of congenital cases attributed to genetic etiologies. In Tunisia, HI underdiagnosis prevails, primarily due to limited access to comprehensive clinical tools, particularly for syndromic deafness (SD), characterized by clinical and genetic heterogeneity. This study aimed to uncover the SD spectrum through a 14-year investigation of a Tunisian cohort encompassing over 700 patients from four referral centers (2007-2021). Employing Sanger sequencing, Targeted Panel Gene Sequencing, and Whole Exome Sequencing, genetic analysis in 30 SD patients identified diagnoses such as Usher syndrome, Waardenburg syndrome, cranio-facial-hand-deafness syndrome, and H syndrome. This latter is a rare genodermatosis characterized by HI, hyperpigmentation, hypertrichosis, and systemic manifestations. A meta-analysis integrating our findings with existing data revealed that nearly 50% of Tunisian SD cases corresponded to rare inherited metabolic disorders. Distinguishing between non-syndromic and syndromic HI poses a challenge, where the age of onset and progression of features significantly impact accurate diagnoses. Despite advancements in local genetic characterization capabilities, certain ultra-rare forms of SD remain underdiagnosed. This research contributes critical insights to inform molecular diagnosis approaches for SD in Tunisia and the broader North-African region, thereby facilitating informed decision-making in clinical practice.

Diagnostic performance of the EU TI-RADS and ACR TI-RADS scoring systems in predicting thyroid malignancy.

INTRODUCTION: Several ultrasound scoring systems have been developed to stratify the risk of malignancy of thyroid nodules, including ACR (American College of Radiology) and EU (European) TI-RADS. This study aimed to assess the diagnostic performance of these two classifications using histology as a reference standard. METHODS: It was a single-centre, retrospective study including 156 patients who underwent thyroidectomy. Ultrasound data of 198 nodules (99 malignant nodules and 99 benign nodules) were analysed. Both classifications were applied for all nodules. RESULTS: Ultrasound criteria associated with malignancy were solid composition (OR=7.81; p < 10-3 ), hypoechoic character (OR=16.42; p < 10-3 ), irregular contours (OR=7.47; p < 10-3 ), taller-than-wide shape (OR=3.58; p = 0.02), microcalcifications (OR=3.02; p = .006) and the presence of cervical adenopathy (OR=3.89; p = .006). The prevalence of malignancy was 15.5%, 69% and 76.9% for EU TI-RADS categories 3, 4 and 5, respectively. It was 33.3%, 57% and 91.1% for ACR TI-RADS categories 3, 4 and 5, respectively. For category 5, EU TI-RADS and ACR TI-RADS had sensitivities of 60% and 41%, specificities of 82% and 96%, respectively. For categories 4 and 5 combined, the diagnostic performance of these two classification systems became comparable with a sensitivity of 89% and 86% for EU-TIRADS and ACR-TIRADS, respectively. The area under the ROC curve was 0.81 for the EU TI-RADS classification and 0.82 for the ACR TI-RADS classification. CONCLUSIONS: EU TI-RADS and ACR TI-RADS scoring systems seem to be comparable in predicting malignancy in thyroid nodules.

Head and neck tuberculosis associated to sarcoidosis: A case report.

The distinction between tuberculosis and sarcoidosis presents sometimes a clinical challenge. Their sequential occurrence in the same patient is uncommon. We present the case of a 42-year-old female with a proven diagnosis of tuberculous lymphadenitis who has developed successively nasal tuberculosis and pulmonary sarcoidosis respectively after 10 and 14 months of antituberculosis treatment. The patient presented with bilateral cervical lymphadenopathy. Tuberculin skin test was negative. Chest radiography was normal. An excision biopsy was taken and histopathological examination established tuberculosis diagnosis. Therapy with antituberculosis drugs was started, and cervical lymphadenopathy showed progressive resolution. Subsequently, nearly 10 months after, the patient developed new cervical lymphadenopathies and nasal obstruction. Tuberculosis of the nasal mucosa was confirmed by biopsy. Antituberclosis bitherapy was enhanced by ofloxacin and ethambutol. Thoracic CT scan showed several nodular elements in both lungs, with bilateral enlarged mediastinal adenopathy. Bronchoalveolar lavage showed a lymphocytic alveolitis with a CD4/CD8 ratio of 5, consistent with the diagnosis of pulmonary sarcoidosis. Corticosteroid treatment, in form of oral prednisolone was introduced, 3 months after sarcoidosis diagnosis have been setteled; because of pulmonary fibrosis noticed on thoracic CT. Systemic corticotherapy was continued for a further period of 3 years, until all the lesions cleared out. The present case emphasizes the possible association between tuberculosis and sarcoidosis.

Ludwig's Angina.

Ludwig's angina is a severe diffuse cellulitis that presents an acute onset and spreads rapidly and bilaterally. It can affect the submandibular, sublingual or submental spaces resulting in a state of emergency. Early diagnosis and urgent management could be a life-saving procedure. We report a case of wide spread sialadenitis infection extending to the neck with trismus and elevation of the floor of the mouth that caused an obstruction of the airway and resulted in an inspiratory dyspnea and a stridor. The patient was directed to maintain the airway by elective tracheostomy. An appropriate use of parenteral antibiotics, airway protection techniques, and potential surgical drainage of the infection remain the standard protocol of treatment in advanced cases of Ludwig's angina. The aim of this case report is to emphasize on the importance of early diagnosis and appropriate management of Ludwig's angina.

Alpha-mannosidosis in Tunisian consanguineous families: Potential involvement of variants in GHR and SLC19A3 genes in the variable expressivity of cognitive impairment.

Alpha-Mannosidosis (AM) is an ultra-rare storage disorder caused by a deficiency of lysosomal alpha-mannosidase encoded by the MAN2B1 gene. Clinical presentation of AM includes mental retardation, recurrent infections, hearing loss, dysmorphic features, and motor dysfunctions. AM has never been reported in Tunisia. We report here the clinical and genetic study of six patients from two Tunisian families with AM. The AM diagnosis was confirmed by an enzymatic activity assay. Genetic investigation was conducted by Sanger sequencing of the mutational hotspots for the first family and by ES analysis for the second one. In the first family, a frameshift duplication p.(Ser802GlnfsTer129) was identified in the MAN2B1 gene. For the second family, ES analysis led to the identification of a missense mutation p.(Arg229Trp) in the MAN2B1 gene in four affected family members. The p.(Ser802GlnfsTer129) mutation induces a premature termination codon which may trigger RNA degradation by the NMD system. The decrease in the levels of MAN2B1 synthesis could explain the severe phenotype observed in the index case. According to the literature, the p.(Arg229Trp) missense variant does not have an impact on MAN2B1 maturation and transportation, which correlates with a moderate clinical sub-type. To explain the intra-familial variability of cognitive impairment, exome analysis allowed the identification of two likely pathogenic variants in GHR and SLC19A3 genes potentially associated to cognitive decline. The present study raises awareness about underdiagnosis of AM in the region that deprives patients from accessing adequate care. Indeed, early diagnosis is critical in order to prevent disease progression and to propose enzyme replacement therapy.

Non-recurrent laryngeal nerve and arteria lusoria: Rare and little known association.

Non-recurrent Laryngeal nerve is constantly associated with Arteria Lusoria. Knowing this association is the basis of predicting this condition preoperatively. Ultrasonography assessment before thyroid and parathyroid surgery should include identification of brachiocephalic trunk division. Absence of its visualization indicates Arteria Lusoria and then non-recurrent laryngeal nerve.

Sudden Death Due to Neck Paraganglioma: A Pediatric Case Report and Review of the Literature.

Neck paragangliomas are relatively rare neuroendocrine nonsecretory tumors. They are mainly observed among adults and are often asymptomatic, causing a frequent delay in diagnosis. In pediatric cases, neck paragangliomas can be associated with adrenergic symptoms that may lead to complications.A report of a sudden death due to a carotid paraganglioma in a young girl is reported. Autopsy revealed a thoracic arotic dissection and a 4-cm jugulocarotidian mass in the absence of traumatic injuries. Histology showed no evidence of underlying aortic disease, including signs of Marfan syndrome, and a paraganglioma. Postmortem biochemistry analysis showed blood metanephrines levels 100 times higher than normal range. The cause of death was an aortic dissection complicating a neck paraganglioma. The manner of death was concluded as natural.Our case highlighted the importance for forensic pathologist to consider the diagnosis of paraganglioma in case of sudden hypertensive complications, especially among young people.

A Tunisian family with a novel mutation in the gene CYP4F22 for lamellar ichthyosis and co-occurrence of hearing loss in a child due to mutation in the SLC26A4 gene.

BACKGROUND: Co-occurrence of two genetic diseases is challenging for accurate diagnosis and genetic counseling. The recent availability of whole exome sequencing (WES) has dramatically improved the molecular diagnosis of rare genetic diseases in particular in consanguineous populations. METHODS: We report here on a consanguineous family from Southern Tunisia including three members affected with congenital ichthyosis. The index case had a hearing loss (HL) and ichthyosis and was primarily suspected as suffering from keratitis-ichthyosis-deafness (KID) syndrome. WES was performed for the index case, and all members of the nuclear family were sequenced (Sanger method). RESULTS: The WES approach allowed the identification of two strong candidate variants in two different genes; a missense mutation c.1334T>G (p.Leu445Trp) in exon 11 of SLC26A4 gene, associated with isolated HL and a novel missense mutation c.728G>T (p.Arg243Leu) in exon 8 of CYP4F22 gene likely responsible for ichthyosis. These two mutations were predicted to be pathogenic by three pathogenicity prediction softwares (Scale-Invariant Feature Transform [SIFT], Polymorphism Phenotyping [PolyPhen], Mutation Taster) to underlie the HL and ichthyosis, respectively. CONCLUSIONS: The present study raises awareness about the importance of familial history for accurate diagnosis of syndromic genetic diseases and differential diagnosis with co-occurrence of two distinct clinical entities. In addition, in countries with limited resources, WES sequencing for a single individual provides a cost effective tool for molecular diagnosis confirmation and genetic counseling.

Papillary thyroid tumors: Diagnostic value of CD56 and Cytokeratin 19.

INTRODUCTION: Noninvasive Follicular Thyroid Neoplasm With Papillary-like Nuclear Features (NIFTP) is a tumor composed exclusively of follicles lined by cells having nuclear characteristics of papillary carcinoma. Morphological diagnosis is often difficult especially in the cases in which these nuclear abnormalities are focal. AIM: To investigate the contribution of the immunohistochemical study with anti CD56 and anti cytokeratin 19 in the positive diagnosis of NIFTP. METHODS: This is a diagnostive, retrospective study of 40 thyroid specimens including 15 NIFTP, 10 classical form papillary carcinoma (CPC) and 15 vesicular adenomas (AV), collected over a period of eighteen months (December 2013-May 2015). RESULTS: Negativity with anti-CD56 was noted in 16 cases: 9 cases of NIFTP and 7 cases of CPC. A diffuse staining was noted in 14 cases of AV. Positivity with anti-Cytokeratin19 was noted in 38 cases: 14 NIFTP, 10 CPC and 14 AV. For the diagnosis of NIFTP, the sensitivity of CD56 was 60% and specificity of 100%. The sensitivity of the Cytokeratin 19 was 93,3 % and specificity of 33,3%. CONCLUSIONS: Considering the good sensitivity and specificity of the CD56, it is possible to apply immunohistochemistry for definitive diagnosis of NIFTP and to differentiate it from adenoma. The cytokeratin 19 does not have a big contribution to distinguish between benign and malignant lesions.

Novel PAX3 mutations causing Waardenburg syndrome type 1 in Tunisian patients.

Waardenburg syndrome (WS) is an auditory-pigmentary disease characterized by a clinical and genetic variability. WS is classified into four types depending on the presence or absence of additional symptoms: WS1, WS2, WS3 and WS4. Type 1 and 3 are mostly caused by PAX3 mutations, while type 2 and type 4 are genetically heterogeneous. The aims of this study are to confirm the diagnostic of WS1 by the sequencing of PAX3 gene and to evaluate the genotype phenotype correlation. A clinical classification was established for 14 patients WS, as proposed by the Waardenburg Consortium, and noted a predominance of type 1 and type 2 with 6 patients WS1, 7 patients WS2 and 1 patient WS3. A significant inter and intra-familial clinical heterogeneity was also observed. A sequencing of PAX3 gene in the 6 patients WS1 confirmed the diagnosis in 4 of them by revealing three novel mutations that modify two functional domains of the protein: the c.942delC; the c.933_936dupTTAC and the c.164delTCCGCCACA. These three variations are most likely responsible for the phenotype, however their pathogenic effects need to be confirmed by functional studies. The MLPA analysis of the 2 patients who were sequence negative for PAX3 gene revealed, in one of them, a heterozygous deletion of exons 5 to 9 confirming the WS1 diagnosis. Both clinical and molecular approaches led to the conclusion that there is a lack of genotype-phenotype correlation in WS1, an element that must be taken into account in genetic counseling. The absence of PAX3 mutation in one patient WS1 highlights the fact that the clinical classification is sometimes insufficient to distinguish WS1 from other types WS hence the interest of sequencing the other WS genes in this patient.

Ectopic thyroid tissue: unusual differential diagnosis of cervical paraganglioma.

Ectopic thyroid tissue (ETT) lateral to the midline is rare. Its occurrence in the carotid bifurcation is exceptional. We present a 45 years woman who consulted with a slow growing right cervical swelling. Clinical examination Ultrasonography, contrast enhanced CT and cervical MRI concluded to a paraganglioma. Intra-operatively, the tumor didn't have the characteristic aspect of a paraganglioma. Complete excision was performed. Histology concluded to an ectopic micro-vesicular thyroid adenoma.Previous literature was reviewed to summarize clinical and radiologic characteristics of such rare entity. Despite its rarity, ETT must be included in the differential diagnosis of cervical paraganglioma.

Paradoxical reaction associated with cervical lymph node tuberculosis: predictive factors and therapeutic management.

OBJECTIVES: The aims of this study were to determine predictive factors of paradoxical reaction in patients with cervical lymph node tuberculosis (TB) and to discuss the therapeutic management of this condition. MATERIALS AND METHODS: A retrospective study was performed of 501 patients managed for cervical lymph node TB over a period of 12 years (from January 2000 to December 2011). Statistical data were analyzed using IBM SPSS Statistics version 20.0. RESULTS: Paradoxical reaction occurred in 67 patients (13.4%), with a median delay to onset after starting TB treatment of 7 months. Lymph node size ≥3cm and associated extra-lymph node TB were independently associated with paradoxical reaction. Treatment consisted of surgical excision (71.6%), restarting quadruple therapy (10.4%), reintroduction of ethambutol (23.8%), and addition of ciprofloxacin (20.8%); steroids were given in two cases . All patients recovered after an average treatment duration of 14.91±7.03 months. CONCLUSION: The occurrence of paradoxical reaction in cervical lymph node TB seems to be predicted by associated extra-lymph node TB and a swelling size ≥3cm. The treatment of paradoxical reaction remains unclear and more randomized trials are necessary to improve its management.

Agressive infection following a dental extraction in a diabetic patient :Rhinocerebral mucormycosis.

Mucormycosis is a rare and acute fungal infection which is frequently lethal, usually observed in non-controlled diabetic patients. The infection usually begins in the nose but it can invade the lung, the digestive tract, and the skin. Rhinocerebral mucormycosis accounts for 40 to 49% of mucormycosis cases. We report the case of a 44-year-old diabetic man, presenting with rhinocerebral mucormycosis. Our patient was treated by an association of amphotericin B and surgical debridement.

Malignant transformation of nasal inverted papilloma into sarcomatoid carcinoma.

A 57 year-old, male presented with a chronic unilateral nasal obstruction and epistaxis. Intranasal endoscopy showed multiple polypoid lesions. The computed tomography exam revealed a heterogeneous mass that occupied the right nasal cavity with osteolysis of the middle and lower cone causing fluid retention of the right maxillary sinus. He underwent resection of these lesions. Pathological examination revealed malignant transformation of nasal inverted papilloma into sarcomatoid carcinoma. This case report highlights the importance of considering malignant transformation in the differential diagnosis of polypoid lesions.

Estimation of Recent and Ancient Inbreeding in a Small Endogamous Tunisian Community Through Genomic Runs of Homozygosity.

Runs of homozygosity (ROHs) are extended genomic regions of homozygous genotypes that record populations' mating patterns in the past. We performed microarray genotyping on 15 individuals from a small isolated Tunisian community. We estimated the individual and population genome-wide level of homozygosity from data on ROH above 0.5 Mb in length. We found a high average number of ROH per individual (48.2). The smallest ROH category (0.5-1.49 Mb) represents 0.93% of the whole genome, while medium-size (1.5-4.99 Mb) and long-size ROH (≥5 Mb) cover 1.18% and 0.95%, respectively. We found that genealogical individual inbreeding coefficients (Fped ) based on three- to four-generation pedigrees are not reliable indicators of the current proportion of genome-wide homozygosity inferred from ROH (FROH ) either for 0.5 or 1.5 Mb ROH length thresholds, while identity-by-descent sharing is a function of shared coancestry. This study emphasizes the effect of reproductive isolation and a prolonged practice of consanguinity that limits the genetic heterogeneity. It also provides evidence of both recent and ancient parental relatedness contribution to the current level of genome-wide homozygosity in the studied population. These findings may be useful for evaluation of long-term effects of inbreeding on human health and for future applications of ROHs in identifying recessive susceptibility genes.

Skeletal facial deformity in patients with ß thalassemia major: Report of one Tunisian case and a review of the literature.

ß Thalassemia is an inherited genetic disorder of hemoglobin synthesis characterized by a reduction of ß chains of globin. Typical features of patients with ß thalassemia are skeletal modifications, particularly in the skull and in the facial bones. In thalassemia major, involvement of the facial skeleton can result in severe disfigurement, often referred to as "rodent facies". Various surgical approaches to correct the facial deformity have been advocated; however, treatment remains controversial. The worse the patient's systemic condition, the more unstable and more complicated the surgical procedure. Patient with multisystemic disorder and severe deformity, such as in our case, with a complete lack of cortical bone for bone fixation, might not be amenable to such procedures. Thorough knowledge of the multiple systemic manifestations, therapy, and prognosis of this syndrome is necessary to formulate a safe, comprehensive surgical plan for these patients.

Whole exome sequencing identifies mutations in Usher syndrome genes in profoundly deaf Tunisian patients.

Usher syndrome (USH) is an autosomal recessive disorder characterized by combined deafness-blindness. It accounts for about 50% of all hereditary deafness blindness cases. Three clinical subtypes (USH1, USH2, and USH3) are described, of which USH1 is the most severe form, characterized by congenital profound deafness, constant vestibular dysfunction, and a prepubertal onset of retinitis pigmentosa. We performed whole exome sequencing in four unrelated Tunisian patients affected by apparently isolated, congenital profound deafness, with reportedly normal ocular fundus examination. Four biallelic mutations were identified in two USH1 genes: a splice acceptor site mutation, c.2283-1G>T, and a novel missense mutation, c.5434G>A (p.Glu1812Lys), in MYO7A, and two previously unreported mutations in USH1G, i.e. a frameshift mutation, c.1195_1196delAG (p.Leu399Alafs*24), and a nonsense mutation, c.52A>T (p.Lys18*). Another ophthalmological examination including optical coherence tomography actually showed the presence of retinitis pigmentosa in all the patients. Our findings provide evidence that USH is under-diagnosed in Tunisian deaf patients. Yet, early diagnosis of USH is of utmost importance because these patients should undergo cochlear implant surgery in early childhood, in anticipation of the visual loss.