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.
View Article and Find Full Text PDFIntroduction: Auditory neuropathy is a hearing disorder where outer hair cell function within the cochlea is normal, but inner hair cell and/or the auditory nerve function is disrupted. It is a heterogeneous disorder, which can have either congenital or acquired causes.
Methods: We found a disease-segregating mutation in the X-linked AIFM1 gene through whole-exome sequencing, encoding the apoptosis-inducing factor mitochondrion-associated 1.
Int J Pediatr Otorhinolaryngol
January 2021
Adhesion glycoproteins are implicated in the pathophysiology of hearing loss, the most frequent inherited sensory disorder, affecting 1 in 1000 new-borns. Exome sequencing of a consanguineous Moroccan patient with mild hearing loss identified for the first time in a North African family a single homozygous mutation c.72delA in MPZL2 gene, encoding the Myelin Protein Zero-Like 2, reported as causing deafness in two other populations.
View Article and Find Full Text PDFMutations in the mesenchymal epithelial transition factor (MET) gene are frequently associated with multiple human cancers but can also lead to human non-syndromic autosomal recessive deafness (DFNB97). In the present study, we identified a novel homozygous missense mutation in the METgene causing a non-syndromic hearing impairment DFNB97 form. Whole-exome sequencing was performed to determine the genetic causes of hearing loss in a Moroccan consanguineous family with an affected daughter.
View Article and Find Full Text PDFBackground: 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.
Int J Pediatr Otorhinolaryngol
October 2018
Objectives: Hearing loss (HL) is one of the most common sensorineural disorders. In the present study, we identified two novel missense mutations in BSND gene causing Bartter syndrome type IV which is a genetic disease with an autosomal recessive transmission, characterized by hypokalaemia, metabolic alkalosis, an elevation in plasma renin activity and hyperaldosteronism as well as sensorineural deafness.
Methods: Whole-exome sequencing was performed to study the genetic causes of Hearing loss in two unrelated patients from two Moroccan families.
Int J Pediatr Otorhinolaryngol
September 2018
Background: Consanguinity rate is high in Algeria, and the population is thus at high risk for genetic diseases transmitted on an autosomal recessive mode. Inherited congenital hearing impairment (HI) is a highly heterogeneous disorder, which affects approximately 1 in 800 Algerian newborns. Several hundreds of genes responsible for deafness have been reported among which more than one hundred are responsible for isolated deafness, of which 19 have already been reported to be involved in the Algerian population.
View Article and Find Full Text PDFDeafness and myopia syndrome is characterized by moderate-profound, bilateral, congenital or prelingual deafness and high myopia. Autosomal recessive non-syndromic hearing loss is one of the most prevalent human genetic sensorineural defects. Myopia is by far the most common human eye disorder that is known to have a clear heritable component.
View Article and Find Full Text PDFMutations in the gene are usually associated with recessive inherited diseases including Zellweger spectrum disorders. In this work, we identified a new pathogenic missense homozygous mutation (p.Leu1026Pro, c.
View Article and Find Full Text PDFUsher syndrome (USH), the most prevalent cause of hereditary deafness-blindness, is an autosomal recessive and genetically heterogeneous disorder. Three clinical subtypes (USH1-3) are distinguishable based on the severity of the sensorineural hearing impairment, the presence or absence of vestibular dysfunction, and the age of onset of the retinitis pigmentosa. A total of 10 causal genes, 6 for USH1, 3 for USH2, and 1 for USH3, and an USH2 modifier gene, have been identified.
View Article and Find Full Text PDFBy genetic linkage analysis in a large consanguineous Iranian family with eleven individuals affected by severe to profound congenital deafness, we were able to define a 2.8 Mb critical interval (at chromosome 1p21.2-1p21.
View Article and Find Full Text PDFEur Arch Otorhinolaryngol
November 2016
Origins of all hearing impairment forms may be divided into genetic mutations and acquired influence. Both carry damage to the inner ear structure resulting in a mild to profound dysfunction of the auditory system. The purpose of this study was to assess the different etiologies of deafness in two reference centers for hearing-impaired children in Nouakchott/Mauritania.
View Article and Find Full Text PDFUsher 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.
View Article and Find Full Text PDFLocated at the cross-road between Europe and Africa, Tunisia is a North African country of 11 million inhabitants. Throughout its history, it has been invaded by different ethnic groups. These historical events, and consanguinity, have impacted on the spectrum and frequency of genetic diseases in Tunisia.
View Article and Find Full Text PDFIdentification of the causative mutations in patients affected by autosomal recessive non syndromic deafness (DFNB forms), is demanding due to genetic heterogeneity. After the exclusion of GJB2 mutations and other mutations previously reported in Tunisian deaf patients, we performed whole exome sequencing in patients affected with severe to profound deafness, from four unrelated consanguineous Tunisian families. Four biallelic non previously reported mutations were identified in three different genes: a nonsense mutation, c.
View Article and Find Full Text PDFInt J Pediatr Otorhinolaryngol
September 2013
Objectives: Mutations in GJB2 are found to be responsible for 50% of congenital autosomal recessive non-syndromic hearing loss, one of the most important mutations in this gene is the c.35delG, which is responsible for the majority of GJB2 related deafness in the Tunisian population. The aim of this study was to determine the molecular etiology of hearing loss in two Tunisian individuals.
View Article and Find Full Text PDFObjectives: Mutations of GJB2 encoding connexin 26 are the most common cause of hearing loss. They are responsible for up to 50% of ARNSHL. The pathogenic mutations in this gene are generally inherited recessively.
View Article and Find Full Text PDFHearing loss is the most frequent sensory disorder. It affects 3 in 1000 newborns. It is genetically heterogeneous with 60 causally-related genes identified to date.
View Article and Find Full Text PDF