Genetic investigation of the ubiquitin-protein ligase E3A gene as putative target in Angelman syndrome

BACKGROUND Angelman syndrome (AS) is caused by maternal chromosomal deletions, imprinting defects, paternal uniparental disomy involving chromosome 15 and the ubiquitin-protein ligase UBE3A gene mutations. However the genetic basis remains unclear for several patients. AIM To investigate the involvement of UBE3A gene in AS and identifying new potential genes using exome sequencing. METHODS We established a cohort study in 50 patients referred to Farhat Hached University Hospital between 2006 and 2021, with a strong suspicion of AS and absence of chromosomal aberrations. The UBE3A gene was screened for mutation detection. Two unrelated patients issued from consanguineous families were subjected to exome analysis. RESULTS We describe seven UBE3A variants among them 3 none previously described including intronic variants c.2220+14T>C (intron14), c.2507+43T>A (Exon15) and insertion in Exon7: c.30-47_30-46. The exome sequencing revealed 22 potential genes that could be involved in AS-like syndromes that should be investigated further. CONCLUSION Screening for UBE3A mutations in AS patients has been proven to be useful to confirm the diagnosis. Our exome findings could rise to new potential alternative target genes for genetic counseling

Case report: 7p22.3 deletion and 8q24.3 duplication in a patient with epilepsy and psychomotor delay—Does both possibly act to modulate a candidate gene region for the patient’s phenotype?

Background: Psychomotor delay, epilepsy and dysmorphic features are clinical signs which are described in multiple syndromes due to chromosomal imbalances or mutations involving key genes implicated in the stages of Early Embryonic Development. In this context, we report a 10 years old Tunisian patient with these three signs. Our objective is to determine the cause of developmental, behavioral and facial abnormalities in this patient.Methods: We used banding cytogenetics (karyotype) and Array Comparative Genomic Hybridization (Array CGH) to this purpose.Results: The karyotype was in favor of a derivative of chromosome 7 in the patient and Array CGH analysis revealed a loss of genetic material in 7p22.3-p22.1 (4,56 Mb) with a gain at 8q24.23-q24 (9.20 Mb) resulting from maternal 7/8 reciprocal translocation. An in silico analysis of the unbalanced region was carried out and showed that the 7p22.3-p22.1 deletion contains eight genes. Among them, BRAT1 gene, previously described in several neurodevelopmental diseases, may be a candidate gene which absence could be correlated to the patient’s phenotype. However, the 8q24.23-q24 duplication could be involved in the phenotype of this patient.Conclusion: In this study, we report for the first time a 7p deletion/8q duplication in a patient with psychomoteur delay, epilepsy and facial dysmorphism. Our study showed that Array CGH still useful for delivering a conclusive genetic diagnosis for patients having neurodevelopmental abnormalities in the era of next-generation sequencing

Further report of MEDS syndrome: Clinical and molecular delineation of a new Tunisian case

International audienceRecently, an autosomal recessive disorder including the triad of microcephaly, infantile epileptic encephalopathy, and permanent neonatal diabetes syndrome (MEDS, OMIM#614231) has emerged as a new distinguishing syndrome. Eight cases of whom seven from Arab countries, have been reported in association with biallelic variants in the IER3IP1 gene (Immediate early response-3 interacting protein-1). Here, we describe a Tunisian boy who presented with permanent neonatal diabetes, microcephaly, generalized seizures and hypovirilized external genitalia consisting of a small genitalia and unilateral cryptorchidism. Chromosomal analysis indicated a 46, XY karyotype in all metaphases. Exome sequencing identified a homozygous missense variant (c.62 T > G; p. Val21Gly) in the IER3IP1 gene, that is predicted to alter the protein structure within the hydrophobic/transmembrane. This variant was previously reported in two cases associated with MEDS. This is the first reported case of MEDS in Tunisia. Our report focuses on the IER3IP1 related phenotypic spectrum and assumes abnormal genitalia as part of the syndrome. Consequently, we recommend to perform hormonal testing on this topic to understand the effect of the IER3IP1 variant on the male genital pathway

A cytogenetic approach to the effects of low levels of ionizing radiation (IR) on the exposed Tunisian hospital workers

Objectives: The aim of this study is to assess chromosomal damage in Tunisian hospital workers occupationally exposed to low levels of ionizing radiation (IR). Materials and Methods: The cytokinesis-block micronucleus (CBMN) assay in the peripheral lymphocytes of 67 exposed workers compared to 43 controls matched for gender, age and smoking habits was used. The clastogenic/aneugenic effect of IR was evaluated using the CBMN assay in combination with fluorescence in situ hybridization with human pan-centromeric DNA in all the exposed subjects and controls. Results: The study showed a signifi cant increase of the micronucleus (MN) frequency in the lymphocytes of the exposed workers compared to the control group (13.63±4.9‰ vs. 6.52±4.21‰, p < 0.05). The centromere analysis performed in our study showed that MNs in hospital staff were predominantly centromere negative (72%) and the mean negative labeled micronucleus (C–MN) frequency was signifi cantly higher in the exposed subjects than in the controls (9.04±4.57‰ vs. 1.17±0.77‰). The multivariate regression analysis, taking into account all confounding factors, showed that only the time of exposure to IR had a signifi cant effect on the level of MNs and C–MN. Conclusion: The present study shows that chromosomal damage leading to the formation of micronucleated lymphocytes is more frequent in the hospital workers exposed to IR than in the controls, despite the low levels of exposure. The results of the study confi rm the well-known clastogenic properties of ionizing radiation. In regards to health monitoring, detection of early genotoxic effects may allow for the adoption of preventive biological control measures, such as hygienic improvements in the workplace or reduction of hours of occupational exposure

Factors associated with anxiety and depression in men undergoing fertility investigations: a cross-sectional study

Abstract Background Infertility is a real public health issue because of its medical, socio-cultural, and financial impact. It does also have heavy psychological consequences on both partners. This study aimed to assess levels of anxiety and depression among men undergoing infertility investigation and to identify their associated factors. Methods We conducted a cross-sectional study in the Laboratory of Cytogenetics and Reproductive Biology of Fattouma Bourguiba University Teaching Hospital (Monastir, Tunisia) between August 30th, 2020, and March 16th, 2021. Anxiety and depression levels were assessed using the valid Arab version of the Hospital Anxiety and Depression scale (HAD). Semen parameters were analyzed and interpreted according to 2021 World Health Organization (WHO) guidelines. Results A total of 282 men were included in the current study. The mean HAD-D (depression) and HAD-A (anxiety) scores were of 6.56 ± 3.07 (IQR [4–8]) and 7.94 ± 3.73 (IQR[5–10]) respectively. Univariate analysis showed that patients having two or more comorbidities were nearly five times more likely to be anxious than those without or with only one comorbidity (ORc = 4.71; p = 0.007). Furthermore, single patients were about four times more anxious than those in couple having primary or secondary infertility (ORc = 3.85; p = 0.027). With regards to semen parameters, patients having hypospermia were more than two times anxious compared with those with normal semen volume (ORc = 2.33; p = 0.034). As for depression, we observed that patients with an infertility history lasting for a year or more have a nine times greater risk of depression (ORc = 9.848; p = 0.007). With regards to semen parameters, patients exhibiting two or more semen abnormalities, teratozoospermia and increased MAI were more depressed (ORc = 2.478; p = 0.036; ORc = 2.549: p = 0.023; ORc = 2.762; p = 0.036). Furthermore, we found a negative correlation between HAD-A scores and patient’s age. Conclusions We pointed out through the current study the associated factors with anxiety and depression in patients under fertility management to precociously identify those who need psychological counseling and hence to better manage infertility issues

Genetic investigation of the ubiquitin-protein ligase E3A gene as putative target in Angelman syndrome

BACKGROUND Angelman syndrome (AS) is caused by maternal chromosomal deletions, imprinting defects, paternal uniparental disomy involving chromosome 15 and the ubiquitin-protein ligase UBE3A gene mutations. However the genetic basis remains unclear for several patients. AIM To investigate the involvement of UBE3A gene in AS and identifying new potential genes using exome sequencing. METHODS We established a cohort study in 50 patients referred to Farhat Hached University Hospital between 2006 and 2021, with a strong suspicion of AS and absence of chromosomal aberrations. The UBE3A gene was screened for mutation detection. Two unrelated patients issued from consanguineous families were subjected to exome analysis. RESULTS We describe seven UBE3A variants among them 3 none previously described including intronic variants c.2220+14T&gt;C (intron14), c.2507+43T&gt;A (Exon15) and insertion in Exon7: c.30-47_30-46. The exome sequencing revealed 22 potential genes that could be involved in AS-like syndromes that should be investigated further. CONCLUSION Screening for UBE3A mutations in AS patients has been proven to be useful to confirm the diagnosis. Our exome findings could rise to new potential alternative target genes for genetic counseling

Partial KCNQ1OT1 hypomethylation: A disguised familial Beckwith–Wiedemann syndrome as a sporadic adrenocortical tumor

Beckwith–Wiedemann syndrome has a wide spectrum of complications such as embryonal tumors, namely adrenocortical tumor. Tumor predisposition is one of the most challenging manifestations of this syndrome. A 45-day old female with a family history of adrenocortical tumor presented with adrenocortical tumor. The case raised suspicion of a hereditary Beckwith–Wiedemann syndrome, therefore molecular analysis was undertaken. The results revealed partial KCNQ1OT1 hypomethylation in the infant's blood DNA which was associated with a complete loss of methylation in the infant's adrenocortical tumor tissue. It is unique for familial Beckwith–Wiedemann syndrome caused by KCNQ1OT1 partial hypomethylation to manifest solely through adrenocortical tumor. Incomplete penetrance and specific tissue mosaicism could provide explanations to this novel hereditary Beckwith–Wiedemann syndrome presentation

Matthew-Wood Syndrome Is Caused by Truncating Mutations in the Retinol-Binding Protein Receptor Gene STRA6

Retinoic acid (RA) is a potent teratogen in all vertebrates when tight homeostatic controls on its endogenous dose, location, or timing are perturbed during early embryogenesis. STRA6 encodes an integral cell-membrane protein that favors RA uptake from soluble retinol-binding protein; its transcription is directly regulated by RA levels. Molecular analysis of STRA6 was undertaken in two human fetuses from consanguineous families we previously described with Matthew-Wood syndrome in a context of severe microphthalmia, pulmonary agenesis, bilateral diaphragmatic eventration, duodenal stenosis, pancreatic malformations, and intrauterine growth retardation. The fetuses had either a homozygous insertion/deletion in exon 2 or a homozygous insertion in exon 7 predicting a premature stop codon in STRA6 transcripts. Five other fetuses presenting at least one of the two major signs of clinical anophthalmia or pulmonary hypoplasia with at least one of the two associated signs of diaphragmatic closure defect or cardiopathy had no STRA6 mutations. These findings suggest a molecular basis for the prenatal manifestations of Matthew-Wood syndrome and suggest that phenotypic overlap with other associations may be due to genetic heterogeneity of elements common to the RA- and fibroblast growth factor–signaling cascades

Additional evidence for the role of chromosomal imbalances and SOX8, ZNRF3 and HHAT gene variants in early human testis development

Abstract Background Forty-six ,XY Differences/Disorders of Sex Development (DSD) are characterized by a broad phenotypic spectrum ranging from typical female to male with undervirilized external genitalia, or more rarely testicular regression with a typical male phenotype. Despite progress in the genetic diagnosis of DSD, most 46,XY DSD cases remain idiopathic. Methods To determine the genetic causes of 46,XY DSD, we studied 165 patients of Tunisian ancestry, who presented a wide range of DSD phenotypes. Karyotyping, candidate gene sequencing, and whole-exome sequencing (WES) were performed. Results Cytogenetic abnormalities, including a high frequency of sex chromosomal anomalies (85.4%), explained the phenotype in 30.9% (51/165) of the cohort. Sanger sequencing of candidate genes identified a novel pathogenic variant in the SRY gene in a patient with 46,XY gonadal dysgenesis. An exome screen of a sub-group of 44 patients with 46,XY DSD revealed pathogenic or likely pathogenic variants in 38.6% (17/44) of patients. Conclusion Rare or novel pathogenic variants were identified in the AR, SRD5A2, ZNRF3, SOX8, SOX9 and HHAT genes. Overall our data indicate a genetic diagnosis rate of 41.2% (68/165) in the group of 46,XY DSD