Molecular approach of auditory neuropathy

Silva, Magali Aparecida Orate Menezes da; Piatto, Vânia Belintani; Maníglia, José Victor

doi:10.1016/j.bjorl.2015.03.005

Cited by 2 publications

(1 citation statement)

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“…The frequency of cases within the auditory neuropathy spectrum found here (3.5%) falls within the prevalence range described in the literature, 1%-19% (Psarommatis et al 1997;Rance 2005;Foerst et al 2006;Maris et al 2011;Silva et al 2015), but higher than another Brazilian study in which it was estimated in 1.2% among cases of deafness (Penido and Isaac 2013). This range of variation may be due to differences in the diagnosis criteria or to population differences.…”

Section: Otof and Auditory Neuropathysupporting

confidence: 70%

Molecular and genetic characterization of a large Brazilian cohort presenting hearing loss

et al. 2021

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Hearing loss is one of the most common sensory defects, affecting 5.5% of the worldwide population and significantly impacting health and social life. It is mainly attributed to genetic causes, but their relative contribution reflects the geographical region's socio-economic development. Extreme genetic heterogeneity with hundreds of deafness genes involved poses challenges for molecular diagnosis. Here we report the investigation of 542 hearing-impaired subjects from all Brazilian regions to search for genetic causes. Biallelic GJB2/GJB6 causative variants were identified in 12.9% (the lowest frequency was found in the Northern region, 7.7%), 0.4% carried GJB2 dominant variants, and 0.6% had the m.1555A > G variant (one aminoglycoside-related). In addition, other genetic screenings, employed in selected probands according to clinical presentation and presumptive inheritance patterns, identified causative variants in 2.4%. Ear malformations and auditory neuropathy were diagnosed in 10.8% and 3.5% of probands, respectively. In 3.8% of prelingual/perilingual cases, Waardenburg syndrome was clinically diagnosed, and in 71.4%, these diagnoses were confirmed with pathogenic variants revealed; seven out of them were novel, including one CNV. All these genetic screening strategies revealed causative variants in 16.2% of the cases. Based on causative variants in the molecular diagnosis and genealogy analyses, a probable genetic etiology was found in ~ 50% of the cases. The present study highlights the relevance of GJB2/GJB6 as a cause of hearing loss in all Brazilian regions and the importance of screening unselected samples for estimating frequencies. Moreover, when a comprehensive screening is not available, molecular diagnosis can be enhanced by selecting probands for specific screenings.

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