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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.

Objective Osteochondrodysplasias are a heterogeneous group of genetic skeletal dysplasias. Mutations in the COL2A1 gene cause a spectrum of rare autosomal-dominant type II collagenopathies characterized by skeletal dysplasia, short stature, and with vision and auditory defects. In this study, we have investigated in more detail the phenotypic and genotypic characterization resulting from glycine to serine mutations in the COL2A1 gene in a 2-year-old boy. Materials and methods Detailed clinical and radiological phenotypic characterization was the baseline tool to guide the geneticists toward proper genotypic confirmation. Results Genetic analysis revealed a de novo mutation, c.1681G>A (p.Gly561Ser), in the collagen type II alpha-1 gene ( COL2A1 ). The identified variant showed impaired protein stability, and lead to dysfunction of type II collagen. In addition to pre and postnatal growth retardation, remarkable retardation of gross motor development and intellectual disability were noted. The latter was connected to cerebral malformations. The overall clinical phenotype of our current patient resembles spondyloepiphyseal dysplasia congenita (SEDC), but with extra phenotypic criteria. Conclusions The aim of this paper is twofold; firstly, raising awareness among orthopaedic surgeons when dealing with children manifesting multiple deformities, and secondly to broaden the clinical phenotype in patients with COL2A1 mutations of amino acid substitution (glycine to serine).

Background Beckwith–Wiedemann syndrome (BWS) is a rare overgrowth syndrome characterized by congenital malformations and predisposition to embryonic tumors. Loss of methylation of imprinting center 2 (IC2) is the most frequent alteration and rarely associated with tumors compared to paternal uniparental disomy of chromosome 11 (UPD(11)pat) and gain of methylation of imprinting center 1. Methods Our study aimed to describe the clinical, histopathological and genetic characteristics of two patients and establish genotype‐phenotype correlations. The clinical diagnosis was based on the criteria defined by the international expert consensus of BWS. Molecular study of 11p15.5 methylation status was assessed using methylation‐specific‐multiplex ligation probe amplification (MS‐MLPA). Results Patients were aged 12 months and 3 months and fulfilled the clinical score of BWS. MS‐MLPA showed molecular alterations consisting of loss of methylation in IC2 (IC2‐LOM) at the maternal allele for one patient and a mosaic UPD(11)pat for the second patient in whom follow‐up at 6months revealed adrenocortical carcinoma (ACC) with low grade of malignancy. Molecular subtypes guide the follow‐up and tumor surveillance, our major concern. Conclusion We have to take into account the psychological impact of a possible tumor whatever the underlying mechanism is. Nevertheless, the tumor risk remains high for UPD(11)pat. Our study extended the phenotype of BWS with absence of macrosomia in Tunisian patients, contrasting with literature, and added a supplementary case of ACC in the tumor spectrum of BWS patients with UPD(11)pat., BWS is a rare overgrowth syndrome predisposing to various tumors. Our major concern is the multidisciplinary follow‐up to early screen tumors. Pathologists should evoke BWS in pediatric isolated adrenocortical tumors. International Databases are necessary to underline BWS’s characteristics.

Non-Immune Hydrops Fetalis (NIHF) is an intrauterine condition characterized by excessive fluid accumulation in at least two fetal compartments in the absence of maternal circulating red cell antibodies. It is associated with a poor prognosis and a wide etiological spectrum. Among the metabolic causes, Mucopolysaccharidosis type VII depicts the most frequent type of lysosomal storage disorders in the cause of NIHF. Nonetheless, it remains an ultra-rare disorder, as less than 150 cases have been reported in the literature. This rarity seems to be related to misdiagnosis since the underlying etiology remains unelusive in most cases of NIHF. In this report, we describe the first Tunisian case of Mucopolysaccharidosis type VII caused by a homozygous mutation in the GUSB gene confirmed by a Next-Generation Sequencing gene panel in a patient with recurrent NIHF.

Background Karyomegalic interstitial nephritis (KIN) is a rare disease entity first described by Burry in 1974. The term KIN was introduced by Mihatsch et al. in 1979. KIN is characterized by chronic tubulointerstitial nephritis associated with enlarged tubular epithelial cell nuclei, which leads to a progressive decline of renal function. The prevalence of this disease is less than 1% of all biopsies, and its pathogenesis is unclear. KIN results from mutations in FAN1 (FANCD2/FANCI-Associated Nuclease 1), a gene involved in the DNA damage response pathway, particularly in the kidney. In this study, we report two Tunisian consanguineous families with KIN caused by mutations in the FAN1 gene. Methods Direct sequencing of the coding regions and flanking intronic sequences of the FAN1 gene was performed in three affected members. Three prediction programs (Polyphen-2 software, SIFT, and MutationTaster) were used to predict the functional effect of the detected variations. Results Two causative frameshift variants in the FAN1 gene were identified in each family: The previously described frameshift mutation c.2616delA (p.Asp873ThrfsTer17) and a novel mutation c.2603delT (p.Leu868ArgfsTer22) classified as "pathogenic" according to the American College of Medical Genetics and Genomics (ACMG) guidelines. Conclusion To our best knowledge, this is the first Tunisian study involving familial cases of KIN with mutations in the FAN1 gene. We hypothesize that these findings can expand the mutational spectrum of KIN and provide valuable information on the genetic cause of KIN.

In humans, mutations of Desert Hedgehog gene (DHH) have been described in patients with 46,XY gonadal dysgenesis (GD), associated or not with polyneuropathy. In this study, we describe two patients diagnosed with GD, both harboring novel DHH compound heterozygous mutations p.[Tyr176*];[Asn337Lysfs*24] and p.[Tyr176*];[Glu212Lys]. To investigate the functional consequences of p.(Asn337Lysfs*24) and p.(Glu212Lys) mutations, located within the C-terminal part of DHh on auto-processing, we performed in vitro cleavage assays of these proteins in comparison with Drosophila melanogaster Hedgehog (Hh). We found that p.(Glu212Lys) mutation retained 50% of its activity and led to a partially abolished DHh auto-processing. In contrast, p.(Asn337Lysfs*24) mutation resulted in a complete absence of auto-proteolysis. Furthermore, we found a different auto-processing profile between Drosophila Hh and human DHh, which suggests differences in the processing mechanism between the two species. Review of the literature shows that proven polyneuropathy and GD is associated with complete disruption of DHh-N, whereas disruption of the DHh auto-processing is only described with GD. We propose a model that may explain the differences between Schwann and Leydig cell development by autocrine versus paracrine DHh signaling. To our knowledge, this is the first study investigating the effect of DHH mutations on DHh in vitro auto-processing.

Background : Shortness of stature, dysmorphic facial features and intellectual disability associated with a broad spectrum of variable psychotic illnesses in a multi-generation family with acrodysostosis. Patients and Methods : The index case is an 8-years-old girl and she was the key factor to explore 33 family subjects over three generations in a Tunisian family with inter-related marriages. 13 male and 20 female subjects over three generations have been studied thoroughly. Eight out of 33 family subjects from both paternal and maternal sides showed craniofacial dysmorphic features, Short stature, intellectual disability, schizophrenia, mental illnesses and other psychotic conditions. Episodes of intermittent claudication associated with walking difficulties were noted in in the index case and low back pain in other family subjects. Results : Clinical and radiological phenotypic characterization was the base line tool to approach the diagnosis of acrodysotosis type II. She and her female sibling showed similar phenotype. Six family subjects have been diagnosed previously of having schizophrenia, psychosis, Tourette’s syndrome and varying degrees of mental illnesses. Eight family subjects out of 33 manifested some of the clinical manifestations of acrodysotosis. Conventional radiographs revealed early signs of spinal stenosis. Conclusion: This is the first study of multigeneration consanguineous Tunisian family in which acrodysostosis was the key factor towards further recognition of other illnesses. Clinical phenotype was the corner stone in the diagnosis of several other affected family subjects. Acrodysostosis displayed imminent role in the pathology of multisystem involvement, specifically a wide range of psychotic illnesses and spinal stensois. Strikingly, this study confirmed that the mechanism of brain development and spinal stenosis should be almost always connected to syndromic associations. To reduce the impact and the aftermath of spinal stenosis in such situations, we need to establish proper clinical documentation of every single patient. In order to prevent and properly intervene we need to establish a distinctive methodology based on comprehensive clinical phenotypic characterization. The compatibility of the clinical phenotype with the genotype is the base line tool of long-run management.&nbsp

Complete gonadal dysgenesis (CGD) is characterized by an incomplete differentiation of the genital organs in a patient with a 46,XY karyotype. It is induced by mutations in the sex-determining region Y (SRY) gene which plays a key role in testis-determining pathways. The aim of this study was to investigate the possible pathogenic nature of a novel SRY mutation (p.Y127H) identified in a 46,XY female patient. To determine the effect of this mutation on SRY function, we studied its impact on DNA interaction by electrophoretic mobility shift assays. Since tyrosine 127 is close to the C-terminal nuclear localization signal of SRY, we conducted HA-SRY protein expression to observe the impact of the mutation on the nuclear import function in transfected cells. Our results showed that the Y127H mutation nearly abolishes the DNA-binding capacity of SRY and strongly impairs the nuclear localization of the mutated protein. Together with a previously described mutation analyzed in parallel in this paper (p.Y127C), our results highlight this tyrosine residue as a crucial structural determinant of the high mobility group box domain. This is the first report to explain the molecular mechanism of the Y127H mutation causing sex reversal and gives new insights for clinical practice to benefit patients with disorders of sex development.

PURPOSE: To explore the three-dimensional (3D) organization of sperm genome in DPY19L2-deficient globozoospermic patients speculating a link between DPY19L2 and genome organization of sperm nucleus. METHODS: This is a study of chromatin organization in DPY19L2-deficient globozoospermic patients and healthy donors using three-dimensional fluorescence in situ hybridization (3D-FISH) combined with confocal laser scanning microscopy followed by 3D image analysis. The 3D structures of sperm nuclei, chromocenter, telomeric regions and chromosome territories (CTs), were reconstructed using IMARIS software, and the relative radial position for each individual signal was calculated. Statistical analysis used a non-parametric Mann-Whitney test was appropriate with significance at p

International audience; BACKGROUND:Cohen syndrome is a rare autosomal recessive developmental disorder that comprises variable clinical features counting developmental delay, pigmentary retinopathy, myopia, acquired microcephaly, truncal obesity, joint hypermobility, friendly disposition and intermittent neutropenia. VPS13B (vacuolar protein sorting 13, yeast, homologue of B) gene is the only gene responsible for Cohen Syndrome, causative mutations include nonsense, missense, indel and splice-site variants. The integrity of the Golgi apparatus requires the presence of the peripheral membrane protein VPS13B that have an essential function in intracellular protein transport and vesicle-mediated sorting.CASE PRESENTATION:In this study, we performed whole exome sequencing (WES) in a Tunisian family with two young cases having developmental delay, hypotonia, autism spectrum disorder, ptosis and thick hair and eyebrows. The proposita presented also pigmentory retinopathy. Compound heterozygous mutation in VPS13B gene was detected by WES. This mutation inherited from healthy heterozygous parents, supports an unpredictable clinical diagnosis of Cohen Syndrome. The proband's phenotype is explained by the presence of compound heterozygous mutations in the VPS13B gene. This finding refined the understanding of genotype-phenotype correlation.CONCLUSIONS:This is the first report of a Tunisian family with Cohen syndrome mutated in the VPS13B gene.

Complete gonadal dysgenesis (CGD) is characterized by an incomplete differentiation of the genital organs in a patient with a 46,XY karyotype. It is induced by mutations in the sex-determining region Y (SRY) gene which plays a key role in testis-determining pathways. The aim of this study was to investigate the possible pathogenic nature of a novel SRY mutation (p.Y127H) identified in a 46,XY female patient. To determine the effect of this mutation on SRY function, we studied its impact on DNA interaction by electrophoretic mobility shift assays. Since tyrosine 127 is close to the C-terminal nuclear localization signal of SRY, we conducted HA-SRY protein expression to observe the impact of the mutation on the nuclear import function in transfected cells. Our results showed that the Y127H mutation nearly abolishes the DNA-binding capacity of SRY and strongly impairs the nuclear localization of the mutated protein. Together with a previously described mutation analyzed in parallel in this paper (p.Y127C), our results highlight this tyrosine residue as a crucial structural determinant of the high mobility group box domain. This is the first report to explain the molecular mechanism of the Y127H mutation causing sex reversal and gives new insights for clinical practice to benefit patients with disorders of sex development.

Mammalian sex is determined by a gene localized on the Y chromosome known as SRY (sex-determining region of the Y chromosome). SRY is a transcription factor that plays a key role in the initiation of the cascade of male sexual differentiation. In 46,XY humans, SRY mutations cause complete gonadal dysgenesis (CGD) with male to female sex reversal, which results in female genitalia without testis differentiation. The aim of this study was to look for mutations of SRY gene in a 46,XY CGD Tunisian female patient by direct sequencing. This method allowed us to identify a novel nonsense mutation L9X, occurring within the NH2 terminal domain of SRY. This novel mutation led to the appearance of a premature stop codon, resulting in a truncated protein, missing the entire HMG box functional domain and the COOH terminal domain. Because of an increased risk of developing gonadoblastoma, early molecular diagnosis allows the orientation of the clinical supervision by removing the dysgenetic gonads to prevent gonadal malignancy. Furthermore, it provides valuable information for the understanding of molecular mechanisms behind the gonadal dysgenesis.

Donohue syndrome (DS) is a rare and lethal autosomal recessive disease caused by mutations in the insulin receptor (INSR) gene, manifesting marked insulin resistance, severe growth retardation, hypertrichosis, and characteristic dysmorphic features. We describe a new case of Donohue syndrome born at 37 weeks' gestation of unrelated parents and presented with intra-uterine growth retardation, nipple hypertrophy, macropenis, distended abdomen, hirsutism and dysmorphic features. The clinical course showed failure to thrive, and episodes of alternating hypoglycemia and hyperglycemia. Laboratory tests revealed direct hyperbilirubinemia. The diagnosis of Donohue syndrome was established based on the above clinical characteristics and determination of the INSR mutation. He was found to have homozygous nonsense mutation c. 2270 C>T (Arg924X) at exon 14 of the INSR gene. He later developed enterocolitis and died at 3 months old. Prenatal diagnosis was performed for the family via chorionic villous biopsy. We try to explain gastrointestinal dysfunction seen in our patient.