Etiology of early hearing loss in Brazilian children

Faistauer, Marina; Silva, Alice Lang; Félix, Têmis Maria; Souza, Liliane Todeschini de; Bohn, Renata; Costa, Sady Selaimen da; Rosito, Letícia Petersen Schmidt

doi:10.1016/j.bjorl.2021.02.012

Cited by 4 publications

(3 citation statements)

References 39 publications

(72 reference statements)

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“…2F, G). The study of Faistauer et al (2021) and the present showed similar results concerning the c.35delG frequency among mutated alleles in the S region, 100% and 90%, respectively, but the present diagnostic rate was higher than the obtained in this study, 14.3% compared to 11.5% (Fig. 2D, F).…”

Section: Brazil's Regional Differences In Gjb2/gjb6 Contribution: Corroborating and Expanding Previous Studiessupporting

confidence: 79%

“…The frequency of HL of genetic etiology reaches 60% in developed countries, while in developing countries, such as in Brazil, this number is expected to be lower due to the outstanding contribution of environmental factors (Braga et al 1999;Faistauer et al 2021). However, owing to the recent improvement in health care, those frequencies should become closer.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Brazil's Regional Differences In Gjb2/gjb6 Contribution: Corroborating and Expanding Previous Studiessupporting

confidence: 79%

Section: Introductionmentioning

confidence: 99%

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

et al. 2021

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“…The differences range from age at implantation, multiple etiologies, and socioeconomic status, leading to unequal access to postoperative rehabilitation. 5 The first CI in Brazil dates to 1977, the second to be performed outside the United States. 6 The CI program in the Brazilian public health system (Sistema Único de Saúde, SUS, in Portuguese) began in the 1990s, and now has more than 40 centers registered to perform this surgery around the country.…”

Section: Introductionmentioning

confidence: 99%

Functional Language in Children from a Public Cochlear Implant Program in a Developing Country

Silva,

Roberto,

Ramos

et al. 2024

Int Arch Otorhinolaryngol

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Introduction The World Health Organization (WHO) estimates that ∼ 32 million children worldwide are affected by hearing loss (HL). Cochlear implant is the first-line treatment for severe to profound sensorineural HL. It is considered one of the most successful prostheses developed to date. Objective To evaluate the oral language development of pediatric patients with prelingual deafness implanted in a reference hospital for the treatment of HL in southern Brazil. Methods We conducted a retrospective cohort study with a review of medical records of patients undergoing cochlear implant surgery between January 2009 and December 2018. Language development was assessed by reviewing consultations with speech therapy professionals from the cochlear implant group. Results A total of 152 children were included in the study. The mean age at cochlear implant surgery was of 41 months (standard deviation [SD]: ± 15). The patients were divided into six groups considering the type of language most used in their daily lives. We found that 36% of children use oral language as their primary form of communication. In a subanalysis, we observed that patients with developed or developing oral language had undergone cochlear implant surgery earlier than patients using Brazilian Sign Language (Língua Brasileira de Sinais, LIBRAS, in Portuguese) or those without developed language. Conclusion The cochlear implant is a state-of-the-art technology that enables the re-establishment of the sense of hearing and the development of oral language. However, language development is a complex process known to present a critical period to properly occur. We still see many patients receiving late diagnosis and treatment, which implies a delay and, often, the impossibility of developing oral communication. Level of Evidence Level 3 (cohort study).

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