Determination of the frequency of the 35delG allele in Brazilian neonates

Sartorato, Edi Lúcia; Gottardi, Elena; Oliveira, Camila Andréa de; Magna, Luís Alberto; Annichino‐Bizzacchi, Joyce Maria; Seixas, Carlos Augusto; Maciel‐Guerra, Andréa Trevas

doi:10.1034/j.1399-0004.2000.580415.x

Cited by 35 publications

(40 citation statements)

References 9 publications

(4 reference statements)

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“…[20][21][22][23] In Brazil, the prevalence of carriers of the 35delG mutation amounted to 0.97%, approximately 1:103 heterozygotes, in a screening carried out in 620 newborns in the region of Campinas, state of São Paulo. 13 The methodology used in the current study was similar to the study carried out in Campinas, so as to maintain the methodological consistency, but some variation was observed in the frequency of alleles containing the 35delG mutation. This fact can be explained by the difference in the sample or maybe because the ethnic composition of the Brazilian population is highly heterogeneous.…”

Section: Discussionmentioning

confidence: 99%

“…In Brazil, a prevalence of 0.9% was described in carriers of the 35delG mutation, that is, 1:103 heterozygotes in a neonatal screening. 13 In another study, now with hearing impaired patients, the 35delG mutation was identified in 84.2% of the alleles. 14 The aim of the present study was to investigate the prevalence of the 35delG mutation, using an allelespecific polymerase chain reaction (AS-PCR) in a sample of newborns, and to draw attention to the necessity of neonatal screening for hearing loss.…”

Section: Introductionmentioning

confidence: 99%

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Perspectivas para triagem da deficiência auditiva genética: rastreamento da mutação 35delG em neonatos

Piatto¹,

Oliveira²,

Alexandrino³

et al. 2005

J. Pediatr. (Rio J.)

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Suggested citation: Piatto VB, Oliveira CA, Alexandrino F, Pimpinati CJ, Sartorato EL. Prospects for genetic hearing loss screening: 35delG mutation tracking in a newborn population. J Pediatr (Rio J). 2005;81:139-42. AbstractObjectives: To investigate the prevalence of the 35delG mutation in a newborn population, with specific molecular testing, and to evaluate the prospects for genetic neonatal screening for hearing impairment.Population and method: 233 newborn were evaluated at the Hospital de Base de São José do Rio Preto, SP, for molecular analysis of the 35delG mutation in the connexin 26 gene, with the reaction technique in allele-specific polymerase chain reaction, after genomic DNA extraction from umbilical cord blood.Results: Five heterozygotes were identified, obtaining a prevalence of 2.24% of 35delG mutation carriers in the study population. Conclusion:Using the molecular test allowed for the identification of the 35delG mutation in the study population with the possibility of being used as a complement to neonatal audiometric screening as being simple, fast, and easily to perform with low costs.J Pediatr (Rio J). 2005;81(2):139-42: 35delG mutation, molecular analysis, hearing impairment, neonatal screening.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Perspectivas para triagem da deficiência auditiva genética: rastreamento da mutação 35delG em neonatos

Piatto¹,

Oliveira²,

Alexandrino³

et al. 2005

J. Pediatr. (Rio J.)

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“…In São Paulo, Brazil this mutation was detected in 2.2% of 223 newborns studied [22], while another screening programme on 620 newborns also conducted in São Paulo indicated a carrier frequency for the mutation of 1.0% [23]. No previous molecular studies in individuals with HI have been conducted in northeastern Brazil, although the c.35delG mutation was identified in individuals of African ancestry with normal hearing ability in Salvador, the state capital of Bahia, where the overall carrier frequency of the mutation was estimated to be 1.0% [24].…”

Section: Introductionmentioning

confidence: 94%

Non-syndromic hearing impairment in a multi-ethnic population of Northeastern Brazil

Manzoli

Abe‐Sandes

Bittles

et al. 2013

International Journal of Pediatric Otorhinolaryngology

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SUMMARYObjective: There are many hearing impaired individuals in Monte Santo, a rural municipality in the state of Bahia, Brazil, including multiple familial cases strongly suggestive of a genetic aetiology.Methods: The present study investigated 81 subjects with hearing impairment (HI) recruited from 36 families. Mutations previously associated with HI were initially analyzed: c.35delG in gene GJB2, del(GJB6-D13S1830) and del(GJB6-D13S1854) in gene GJB6, and A1555G in the mitochondrial gene MTRNR1, with additional mutations in GJB2 identified by sequencing the coding region of the gene.Results: Seven different mutations were present in GJB2 with mutations c.35delG and p.R75Q, which are known to be pathogenic, identified in 37.0% of the subjects. Individuals homozygous for the c.35delG mutation were diagnosed in eight families, corresponding to 24.6% of unrelated individuals with nonsyndromic hearing impairment (NSHI), and an additional heterozygote for this mutation was present in a single family. Ten individuals (12.4%) in another family were heterozygous for the mutation p.R75Q. Conclusions:Significant heterogeneity was observed in the alleles and patterns of NSHI inheritance among the subjects studied, probably due to the extensive inter-ethnic admixture that characterizes the peoples of Brazil, and a high prevalence of community endogamy and consanguineous marriage.

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“…In Brazil, a study conducted in newborns from the region of Sao Jose do Rio Preto, SP 33 , found a 2.24% (1:44.6) prevalence of heterozygotes for the 35delG mutation, and another newborn screening, performed in the region of Campinas, SP 34 , found a 0.97% (1:103) prevalence of heterozygotes. In another study, performed in patients with hearing loss, mutations in the GJB2 gene were found in 33.5% of cases, and only the 35delG mutation was identified in 84.2% of mutant alleles 14 .…”

Section: Ic -Index Cases; Hl -Hearing Lossmentioning

confidence: 99%

Correlação entre dados audiométricos e mutação 35delG em dez pacientes

Piatto

Moreira

Silva

et al. 2007

Rev. Bras. Otorrinolaringol.

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Mutações no gene da conexina 26 parecem ser extremamente comuns na gênese da surdez hereditária não-sindrômica, especialmente, a mutação 35delG, mas ainda há poucos estudos que descrevem as características audiométricas dos pacientes portadores dessas mutações. OBJETIVO: Analisar as características audiométricas em pacientes com mutações no gene da conexina 26 para se delinear uma correlação genótipo-fenótipo. CASUÍSTICA E MÉTODO: Foram avaliadas audiometrias tonal de 33 casos-índice com surdez sensorioneural não-sindrômica e de 8 familiares afetados. Testes moleculares específicos foram realizados para analisar mutações no gene da conexina 26. FORMA DE ESTUDO: Estudo de casos, retrospectivo, em corte transversal. RESULTADOS: Foram encontradas as prevalências de 27,3% da mutação 35delG nos casos-índice e de 12,5% nos familiares afetados. Em relação aos graus de perda, foram encontrados, 41,5% dos pacientes com grau profundo, 39,0% com grau grave e 19,5% com grau moderado com, os pacientes homozigotos e heterozigotos para 35delG, predominando nos graus moderado-grave. CONCLUSÃO: Estes resultados sugerem que os dados audiométricos, associados ao diagnóstico molecular para a surdez, permitiram delinear uma correlação genótipo-fenótipo em dez pacientes com a mutação 35delG. Mas é necessário estudo multicêntrico para se verificar a real expressão fenotípica na população brasileira relacionada à mutação 35delG.

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Determination of the frequency of the 35delG allele in Brazilian neonates

Cited by 35 publications

References 9 publications

Perspectivas para triagem da deficiência auditiva genética: rastreamento da mutação 35delG em neonatos

Perspectivas para triagem da deficiência auditiva genética: rastreamento da mutação 35delG em neonatos

Non-syndromic hearing impairment in a multi-ethnic population of Northeastern Brazil

Correlação entre dados audiométricos e mutação 35delG em dez pacientes

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