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Hearing Loss in Childhood
Published in Raymond W Clarke, Diseases of the Ear, Nose & Throat in Children, 2023
The specific genetic defect is not always established, but improved detection techniques and gene sequencing are leading to the regular reporting of new gene mutations causing non-syndromic deafness. Mutations in the gene that codes for connexin 26 – a gap junction protein – are a particularly common finding in permanent congenital hearing impairment (PCHI).
Genomics and Hearing Loss: Toward a New Standard of Care?
Published in Stavros Hatzopoulos, Andrea Ciorba, Mark Krumm, Advances in Audiology and Hearing Science, 2020
Nonsyndromic HL is not associated with visible abnormalities of the external ear or any related medical problems involving other organs. It can be associated with anomalies of the middle or inner ear, however. Nonsyndromic hearing loss represents about 70% of congenital hereditary deafness with mutations predominantly inherited in an autosomal recessive pattern. This type of hearing loss may be referred to by the gene involved (OTOF for example) or by the genetic locus (DFNB9 for example). Nonsyndromic deafness loci are designated DFN (DeaFNess) and further classified by the mode of inheritance: DFNA: autosomal dominant; DFNB: autosomal recessive; DFNX: X-linked, then followed by a number indicating the order of gene mapping and/or discovery.
Deafness
Published in Angus Clarke, Alex Murray, Julian Sampson, Harper's Practical Genetic Counselling, 2019
At least 50% of cases of congenital and childhood deafness may be genetically determined. In the case of non-syndromic deafness, a precise clinical diagnosis may be impossible owing to phenotypic overlap with deafness of environmental origin. Careful attention to family history and detailed audiological evaluation, not just of the proband but also of other family members, may help to resolve the question of aetiology in apparently isolated cases. Close consultation with audiological colleagues and others is needed if errors are to be avoided.
Mutation spectrum and hotspots of the common deafness genes in 314 patients with nonsyndromic hearing loss in Heze area, China
Published in Acta Oto-Laryngologica, 2019
Meng Zhang, Yuechen Han, Fengguo Zhang, Xiaohui Bai, Haibo Wang
Three hundred and fourteen individuals diagnosed with nonsyndromic deafness from Heze area were included in this study. Among these subjects, 246 patients were simplex and did not have a family history of hearing loss, while 68 subjects were multiplex, with their lineal relative suffering from deafness. Furthermore, 203 males and 111 females were included in this investigation. The age of subjects at the test varied from 3 years to 24 years. Based on the age distribution, we designed three age groups: 0–6 years (including 6-year old) (69 probands), 6–18 years (216 probands), and 18–35 years (29 probands). In addition, most of the individuals (307 probands) had an early age of onset (≤6 years), while only seven probands underwent hearing loss after 6-year old. Finally, according to the results of pure-tone audiometry, 288 probands experienced severe to profound level of hearing impairment, while only 19 moderate and 7 mild hearing loss probands were identified by the auditory test (Table 1). The classification standard of the severity of hearing loss has been described previously.
Evaluating inter-aural hearing preservation in bilateral paediatric cochlear implantation
Published in Cochlear Implants International, 2018
Huw A. S. Jones, Harry R. F. Powell, Andy Hall, Jeremy Lavy, Azhar Shaida, Shakeel Saeed, Sherif Khalil
Analysis of the cochlear implant database identified a total of 31 children implanted in the study period, 7 of whom (1 male; 6 female) underwent simultaneous bilateral CI. The ages ranged from 6 to 18 with a mean of 12 years 11 months at the time of surgery. One patient had suffered profound bilateral sensorineural hearing loss secondary to meningitis (patient 4); the remaining six patients had congenital, non-syndromic deafness of unknown aetiology. These were patients with any preservable hearing, rather than being specifically identified with the aim of future combined electric/acoustic stimulation. The mean time between pre- and post-implant audiograms was 15 ± 7 months. In all cases, a FLEX 28 array was inserted through the round window membrane. For 11/14 ears, full insertion was achieved. There were three incomplete insertions with 2/19 extra-cochlear electrode contacts in each case (Table 1).
Detecting novel mutations and combined Klinefelter syndrome in Usher syndrome cases
Published in Acta Oto-Laryngologica, 2019
Xiaohong Li, Shasha Huang, Yongyi Yuan, Yu Lu, Dejun Zhang, Xiaobin Wang, Huijun Yuan, Weiju Han, Pu Dai
We have described four novel mutations in two probands with USH1. Our study expands the spectrum of MYO7A mutations in USH. This is also the first report of a molecularly diagnosed case of concomitant USH and KS, which was initially diagnosed as nonsyndromic deafness. These cases show the importance of genetic evaluation for early diagnosis of congenital diseases. The results of genetic testing can inform clinical management, particularly if an unrecognized syndromic form of hearing loss is identified before the onset of additional symptoms. A clinical genetic evaluation is recommended as part of the diagnostic work-up in congenital hearing loss.