4 research outputs found

    Genetic study of 45 big hearing loss pedigrees and GJB2 gene mutations frequency in Chaharmahal va Bakhtiari province, Iran, 2008

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    Background and aim: Hearing loss is the most common sensorineural disorder in human. Despite the contribution of several different genes in causing deafness, mutations in the GJB2 gene have been involved in deafness in many populations. This study aims to investigate genetic epidemiology and frequency of GJB2 gene mutations in 45 big deaf pedigrees. Methods: In this genetic epidemiology study we have investigated 45 big deaf pedigrees concerning inheritance patterns, consanguinity and diversity of deafness severity among siblings using data collected by questionnaires and audiograms. We examined also the frequency and profile of GJB2 gene mutations in 45 probands using direct sequencing strategy. Results: Our study revealed 73% of consanguinity in the deaf pedigrees studied. The most common type of first cousins marriage was found between first cousins who were the children of two brothers. We found autosomal recessive and X-linked recessive pattern in 94-97% and 3-6% of the pedigrees studied respectively. Regarding molecular analysis, GJB2 mutations were found in 11% of population studied including 35delG, 167delT, 299-300delAT and 363delC. Conclusion: A high rate of consanguineous marriage determined in this study could raise the rate of autosomal recessive patterns up to 94-97% of the overall pedigree and would be the main cause to prepare the way for congenital deafness. This study revealed a low contribution of GJB2 gene mutations in causing deafness in Chaharmahal va Bakhtiari province

    The frequenc of hearing loss etiology among deaf students in Chaharmahal va Bakhtiari province Iran 2008-2009

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    چکیده: زمینه و هدف: ناشنوایی شایع ترین اختلال حسی در انسان می باشد که تاثیرات اقتصادی و اجتماعی شدیدی در دنیای مدرن دارد. از نظر اتیولوژی، ناشنوایی به دو دسته ژنتیکی و غیر ژنتیکی تقسیم می شود که ناشنوایی ژنتیکی در دو گروه سندرمیک و غیر سندرمیک طبقه بندی می گردد. این مطالعه با هدف تعیین اتیولوژی ناشنوایی در دانش آموزان ناشنوای استان چهارمحال و بختیاری انجام شد. روش بررسی: در این مطالعه توصیفی 265 دانش آموز ناشنوای خفیف تا عمیق شرکت داشتند. نمونه ها شامل دانش آموزان ناشنوای مدارس استان چهارمحال و بختیاری بودند که دامنه سنی آنها بین 6 تا 22 سال بود. سابقه پزشکی، شجره نامه و اطلاعات دموگرافیک بیماران با استفاده از پرسشنامه جمع آوری گردید. تمام بیماران مورد معاینه عمومی و شنوایی قرار گرفته و تست Pure Tone Audiometry) PTA) برای کلیه دانش آموزان و تست ABR (Auditory Brainstem Response)، OAE(Otoacoustic Emissions) در بیماران مشکوک به ناشنوایی عصبی انجام شد. یافته ها: 2/67 از والدین دانش آموزان ناشنوا ازدواج خویشاوندی داشته و شایع ترین شکل این ازدواج، ازدواج بین خویشاوندان درجه 3 (1/78) بود. نتایج مطالعه نشان داد که 8/98 موارد ناشنوایی ژنتیکی به شکل اتوزمال مغلوب و در 8/97 موارد ناشنوایی از نوع حسی عصبی بود. از نظر اتیولوژی ناشنوایی با علت ژنتیکی، شایع ترین علت ناشنوایی(8/60) و سپس ناشنوایی با علل ناشناخته و اکتسابی بیشترین موارد را تشکیل می دادند. در 2/4 از دانش آموزان علل سندرمیک مطرح و مشکلات چشمی بیشترین ناهنجاری همراه با ناشنوایی بود. در بین علل اکتسابی نیز بیشترین عامل ناشنوایی به ترتیب مربوط به کرنیکتروس و تشنج همراه با تب بود. نتیجه گیری: نتایج این مطالعه اهمیت مشکلات مربوط به ازدواج های خویشاوندی را در جمعیت مورد مطالعه نشان می دهد. میزان این ازدواج ها در جمعیت مورد مطالعه بسیار بالا (2/67) بوده که می تواند علت اصلی ناشنوایی مادرزادی باشد

    Study of the association of DFNB3 locus with autosomal recessive non-syndromic hearing loss in iranian deaf population using genetic linkage analysis

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    Background: Hearing loss is a common sensory disorder that typically illustrates genetic heterogeneity in human populations. The incidence of congenital hearing loss is estimated at 1 in 500 births of which approximately 70 of cases are attributed to genetic factors. Genetic hearing impairment can be classified as either syndromic or non-syndromic and among non-syndromic hearing loss autosomal recessive (ALNSHL) accounts for approximately 75-80 of cases. This type of hearing loss is extremely heterogeneous and includes over 100 loci. For recessive deafness, most frequent genes are GJB2, SLC26A4, MYO15A, OTOF, and CDH23 in worldwide. This study aimed to determine the role of MYO15A (DFNB3) gene mutations in Iranian deaf population using linkage analysis. Methods: To investigate the frequency of DFNB3 gene mutation, linkage analysis was performed in 30 Iranian families with over three deaf child and negative GJB2. The negative mutations pedigrees for these gene mutations were then tested for the linkage to DFNB3 (MYO15A) locus, using short tandem repeat (STR) markers. Findings: Mutation 35delG was identified in 5 families out of 30 by sequencing the coding region of GJB2 gene. One family showed linkage to DFNB3 locus. Conclusion: Based on the results of this study, DFNB3 locus is the third cause of deafness after DFNB1 (GJB2) and DFNB4 (SLC26A4). © 2014, Isfahan University of Medical Sciences(IUMS). All rights reserved

    DFNB59 Gene Mutation Screening Using PCR-SSCP/HA Technique in Non-syndromic Genetic Hearing Loss in Bushehr Province

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    Background: Hearing impairment (HI) is the most prevalent Neurosensory disorder which is heterogenous and can also occur due to environmental causes. The majority of hearing deficiencies are of genetic origin affecting about 60% of the HI cases. A novel gene DFNB59 encodes pejvakin has been recently shown to cause deafness. This study aims to determine the frequency of DFNB59 gene mutations in coding region the gene in Bushehr province. Methods: In this descriptive experimental study, we investigated the presence of DFNB59
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