Hereditary nonsyndromic hearing impairment (HI) is extremely heterogeneous. Mutations of the transmembrane channel-like gene 1 (TMC1) have been shown to cause autosomal dominant and recessive forms of nonsyndromic HI linked to the loci DFNA36 and DFNB7/B11, respectively. TMC1 is 1 member of a family of 8 genes encoding transmembrane proteins. In the mouse, MmTmc1 and MmTmc2 are both members of Tmc subfamily A and are highly and almost exclusively expressed in the cochlea. The restricted expression of Tmc2 in the cochlea and its close phylogenetic relationship to Tmc1 makes it a candidate gene for nonsyndromic HI. We analyzed 3 microsatellite markers linked to the TMC1 and TMC2 genes in 85 Tunisian families with autosomal recessive nonsyndromic HI and without mutations in the protein-coding region of the GJB2 gene. Autozygosity by descent analysis of 2 markers bordering the TMC2 gene allowed us to rule out its association with deafness within these families. However, 5 families were found to segregate deafness with 3 different alleles of marker D9S1837, located within the first intron of the TMC1 gene. By DNA sequencing of coding exons of TMC1 in affected individuals, we identified 3 homozygous mutations, c.100C→T (p.R34X), c.1165C→T (p.R389X) and the novel mutation c.1764G→A (p.W588X). We additionally tested 60 unrelated deaf Tunisian individuals for the c.100C→T mutation. We detected this mutation in a homozygous state in 2 cases. This study confirms that mutations in the TMC1 gene may be a common cause for autosomal recessive nonsyndromic HI.
Recessive mutations of MYO15A are associated with nonsyndromic hearing loss (HL) in humans (DFNB3) and in the shaker-2 mouse. Human MYO15A has 66 exons and encodes unconventional myosin XVA. Analysis of 77 Tunisian consanguineous families segregating recessive deafness revealed evidence of linkage to microsatellite markers for DFNB3 in four families. In two families, sequencing of MYO15A led to the identification of two novel homozygous mutations: a nonsense (c.4998C>A (p.C1666X) in exon 17 and a splice site mutation in intron 54 (c.9229 + 1G>A). A novel mutation of unknown significance, c.7395 + 3G>C, was identified in the third family, and no mutation was found in the fourth family. In conclusion, we discovered three novel mutations of MYO15A, and our data suggest the possibility that there are two distinct genes at the DFNB3 locus.
INTRODUCTIONLe mal de Pott sous occipital est défini par l'atteinte tuberculeuse des deux premières vertèbres cervicales et des articulations occipito-atloïdiennes et atloïdo-axoidiennes. Il s'agit d'une localisation exceptionnelle de la tuberculo-se ostéoarticulaire et représente 0,5 à 5 % des atteintes rachidiennes. Le motif de consultation le plus fréquent est représenté par les cervicalgies. Cependant, la dysphagie et l'abcès rétro pharyngien peuvent être aussi révélateurs du mal de Pott sous occipital.
RESUME Introduction : Les surdités brusques idiopathiques (SBI) constituent l'un des sujets les plus débattus en otologie. Plusieurs problèmes d'ordre physiopathologiques, thérapeutiques et pronostiques restent non résolus. But : Identifier les facteurs pronostiques, cliniques et audiométriques de récupération auditive après traitement d'une SBI. Malades : Etude rétrospective portée sur 27 malades (29 cas de SBI) traités dans le service d'ORL et chirurgie cervicofaciale du CHU Habib Bourguiba Sfax durant la période comprise entre les années 1990 et 2005. Méthodes : C'est une étude statistique recherchant une corrélation significative entre certains facteurs cliniques et audiométriques et la récupération auditive. Les facteurs étudiés étaient : l'âge, l'aspect de la courbe audiométrique, la perte auditive initiale et le délai de prise en charge thérapeutique. Résultats : L'âge inférieur à 50 ans, la courbe ascendante et la perte auditive inférieure à 70 dB étaient les facteurs de meilleur pronostic. Le délai de prise en charge thérapeutique semble avoir peu de rôle dans la récupération auditive. Discussion : La majorité des auteurs ont signalé que l'âge jeune, les surdités légères ou moyennes, la courbe ascendante et la précocité de la prise en charge sont associés à un meilleur pronostic. Nos résultats rejoignent ceux de Tran Ba Huy qui ne trouve pas de corrélation entre le délai de prise en charge thérapeutique et le pronostic de récupération auditive. Mots clés : Surdité brusque, facteurs pronostiques, courbe audiométrique, urgence thérapeutique. SUMMARY Introduction : Idiopathic Sudden Sensorineural Hearing Loss (ISSHL) remains one of the major otologic debates. Many etiopathogenic, therapeutic and prognostic problems are still unsolved. Purpose : Identify some clinical and audiometric factors influencing the recovery prognostic after treatment of ISSHL. Patients : Retrospective study of 27 patients (29 cases of ISSHL) treated in the department of Oto-Rhino-Laryngology and Head and Neck Surgery of Habib Bourguiba Hospital during the period from 1990 to 2005. Method: We underwent a statistical data to search a significant correlation between some clinical, audiometric factors and hearing recovery. The factors studied are: age of patient, the type of the tonal audiogram shape, the degree of the initial hearing loss and the therapeutic delay. Results: The age under 50 years, the ascending audiogram shape and initial hearing loss under 70dB involve a better prognostic. The therapeutic delay seems have a little role in the hearing recovery. Discussion: The majority of authors concluded that the young age, the mild and moderate hearing loss, the ascending audiogram shape and the precocity of treatment are correlated to a better prognostic. We, as Tran Ba Huy, don't find a significant correlation between the therapeutic delay and the quality of hearing recovery.
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