Connexin gene mutations among ugandan patients with nonsyndromic sensorineural hearing loss

Javidnia, Hedyeh; Carson, Nancy; Awubwa, Michael; Byaruhanga, Richard; Mack, David R.; Vaccani, Jean‐Philippe

doi:10.1002/lary.24697

Cited by 15 publications

(14 citation statements)

References 30 publications

(63 reference statements)

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“…Other studies have shown differences in genes coding for deafness in certain ethnic minorities [16][17][18][19][20]. Alternative explanations could be infections, prematurity, and neonatal complications [21], but this is less likely in view of the evenly distributed comorbidity in the present study.…”

Section: Incidence Rate Of Cochlear Implant Versus Ethnicitycontrasting

confidence: 57%

The impact of ethnicity on cochlear implantation in Norwegian children

Amundsen

Wie

Myhrum

et al. 2017

International Journal of Pediatric Otorhinolaryngology

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The incidence of CI was significantly higher in children with a non-Nordic vs. a Nordic ethnicity, reflecting a higher incidence of profound deafness. Children born in Norway have equal access to CIs regardless of their ethnicity, but despite being born and receiving care in Norway, prelingually deaf children with non-Nordic parents are at risk of receiving CI later than Nordic children. Moreover, prelingually deaf children who arrive in Norway at an older age may be at risk for a worse prognosis after receiving a CI due to lack of auditory stimulation in early childhood, which is critical for language development and late implantation; this is a serious issue with regard to deafness among refugees.

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Section: Incidence Rate Of Cochlear Implant Versus Ethnicitycontrasting

confidence: 57%

The impact of ethnicity on cochlear implantation in Norwegian children

Amundsen

Wie

Myhrum

et al. 2017

International Journal of Pediatric Otorhinolaryngology

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“…Mutations in GJB6, including the 342-kb deletion, GJB6-D13S1830, were not reported in cohorts of 182, 44 and 401 probands from South Africa, Nigeria and Ghana, respectively [18,69,70]. As in the Cameroonian population, disease-causing mutations in GJB2 are also less prevalent or absent in populations from Kenya, Sudan, Uganda, Nigeria, Mauritania and South Africa [5,33,[69][70][71][72].…”

Section: Discussionmentioning

confidence: 91%

Hearing Impairment Overview in Africa: the Case of Cameroon

Tingang

Noubiap

Fokouo³

et al. 2020

Genes

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The incidence of hearing impairment (HI) is higher in low- and middle-income countries when compared to high-income countries. There is therefore a necessity to estimate the burden of this condition in developing world. The aim of our study was to use a systematic approach to provide summarized data on the prevalence, etiologies, clinical patterns and genetics of HI in Cameroon. We searched PubMed, Scopus, African Journals Online, AFROLIB and African Index Medicus to identify relevant studies on HI in Cameroon, published from inception to 31 October, 2019, with no language restrictions. Reference lists of included studies were also scrutinized, and data were summarized narratively. This study is registered with PROSPERO, number CRD42019142788. We screened 333 records, of which 17 studies were finally included in the review. The prevalence of HI in Cameroon ranges from 0.9% to 3.6% in population-based studies and increases with age. Environmental factors contribute to 52.6% to 62.2% of HI cases, with meningitis, impacted wax and age-related disorder being the most common ones. Hereditary HI comprises 0.8% to 14.8% of all cases. In 32.6% to 37% of HI cases, the origin remains unknown. Non-syndromic hearing impairment (NSHI) is the most frequent clinical entity and accounts for 86.1% to 92.5% of cases of HI of genetic origin. Waardenburg and Usher syndromes account for 50% to 57.14% and 8.9% to 42.9% of genetic syndromic cases, respectively. No pathogenic mutation was described in GJB6 gene, and the prevalence of pathogenic mutations in GJB2 gene ranged from 0% to 0.5%. The prevalence of pathogenic mutations in other known NSHI genes was <10% in Cameroonian probands. Environmental factors are the leading etiology of HI in Cameroon, and mutations in most important HI genes are infrequent in Cameroon. Whole genome sequencing therefore appears as the most effective way to identify variants associated with HI in Cameroon and sub-Saharan Africa in general.

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“…There was, however, a high frequency of two GJB2 variants, C>T at position g.3318-3315 and C>T at p osition g.3318-3334, which occurred in 21.4% and 46.2% of the deaf cohort respectively, and in 35% and 42.6% of a normal hearing control group, respectively, suggesting that these are common nonpathogenic polymorphisms (Kabahuma et al, 2011). These variants were also found with high frequency in populations from Cameroon, Uganda, Kenya, and Sudan, supporting their role as benign polymorphisms (Gasmelseed et al, 2004;Bosch et al, 2014;Javidnia et al, 2014).…”

Section: Gjb2mentioning

confidence: 94%

“…GJB2 mutations were also absent among deaf probands from the Yoruba tribe residing in Ibadan, a suburban city in Nigeria (Lasisi et al, 2014). Similarly, an analysis of a large cohort of Ugandan deaf patients identified none of the common GJB2 deletions (Javidnia et al, 2014). Despite low rates of common GJB2 mutations in the Ugandan population, complete sequencing of 115 of the 126 individuals revealed one pathogenic variant in GJB2 (c.208C>G; p.Pro70Ala) (Javidnia et al, 2014).…”

Section: Gjb2mentioning

confidence: 99%

“…Similarly, an analysis of a large cohort of Ugandan deaf patients identified none of the common GJB2 deletions (Javidnia et al, 2014). Despite low rates of common GJB2 mutations in the Ugandan population, complete sequencing of 115 of the 126 individuals revealed one pathogenic variant in GJB2 (c.208C>G; p.Pro70Ala) (Javidnia et al, 2014). Analysis of the coding region of the GJB2 gene in 205 Cameroonian and Xhosa South Africans with congenital, non-syndromic deafness, also revealed low frequencies of common mutations but identified two monoallelic pathogenic mutations (p.F142del and p.V167M) in two unrelated Cameroonian participants (Bosch et al, 2014).…”

Section: Gjb2mentioning

confidence: 99%

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The genetic basis of deafness in populations of African descent

Rudman

Kabahuma

Bressler

et al. 2017

Journal of Genetics and Genomics

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Hearing loss is the most common sensorineural disorder worldwide and is associated with more than 1000 mutations in more than 90 genes. While mutations in genes such as GJB2 (gap-junction protein β 2) and GJB6 (gap-junction protein β 6) are highly prevalent in Caucasian, Asian, and Middle Eastern populations, they are rare in both native African populations and those of African descent. The objective of this paper is to review the current knowledge regarding the epidemiology and genetics of hearing loss in African populations with a focus on native sub-Saharan African populations. Environmental etiologies related to poor access to healthcare and perinatal care account for the majority of cases. Syndromic etiologies including Waardenburg, Pendred and Usher syndromes are uncommon causes of hearing loss in these populations. Of the non-syndromic causes, common mutations in GJB2 and GJB6 are rarely implicated in populations of African descent. Recent use of next-generation sequencing (NGS) has identified several candidate deafness genes in African populations from Nigeria and South Africa that are unique when compared to common causative mutations worldwide. Researchers also recently described a dominant mutation in MYO3a in an African American family with non-syndromic hearing loss. The use of NGS and specialized panels will aid in identifying rare and novel mutations in a more cost- and time-effective manner. The identification of common hearing loss mutations in indigenous African populations will pave the way for translation into genetic deafness research in populations of African descent worldwide.

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Connexin gene mutations among ugandan patients with nonsyndromic sensorineural hearing loss

Abstract: None of the most common types of deletions in the GJB2 gene (c.35delG, c.167delT or c.235delC) were found in this large cohort of deaf children from Uganda. This prompts a search for genetic causes of deafness among this and other previously studied African populations.

Cited by 15 publications

References 30 publications

The impact of ethnicity on cochlear implantation in Norwegian children

The impact of ethnicity on cochlear implantation in Norwegian children

Hearing Impairment Overview in Africa: the Case of Cameroon

The genetic basis of deafness in populations of African descent

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