1,720,967 research outputs found
Identification and clinical implications of a novel pathogenic variant in the GJB2 gene causes autosomal recessive non-syndromic hearing loss in a consanguineous Iranian family
Full text linkMutations in the GJB2 gene, which encodes the connexin26 protein and is involved in inner ear homeostasis, are the most common cause of autosomal recessive non-syndromic hearing loss (ARNSHL) in many populations. This study was aimed to determine the molecular etiology in a consanguineous Iranian family affected by profound ARNSHL. A comprehensive family history was obtained, and clinical evaluations and pedigree analysis were performed in the family with 4 affected members. After extraction of genomic DNA, the entire coding region of GJB2 was directly sequenced in all family members. In silico analyses were also performed using available software tools. Sanger sequencing results showed a novel rare homozygous variant (c.109_110insG) in the GJB2 gene. This frameshift variant in exon 2 of the GJB2 gene fulfills the criteria of being categorized as pathogenic according to the American College of Medical Genetics and Genomics (ACMG) guideline. Confirmation was done with the co-segregation study and checking the frequency of the novel variant in 100 ethnically matched normal control subjects. The present study suggests that investigation of GJB2 mutations may still be useful to determine the etiology of HL in Iran.
Keywords:autosomal recessive non-syndromic hearing loss; GJB2; ACMG guideline; Ira
Genetics of Hereditary Hearing Loss in the Middle East: A Systematic Review of the Carrier Frequency of the GJB2 Mutation (35delG)
No full textBackground and Objectives: Mutations in the GJB2 gene are a major cause of hearing loss in many populations. A single mutation of this gene (c.35delG) accounts for approximately 70% of mutations in Caucasians with a carrier frequency of 2-4% in Europe. This study aims to determine the rate of c.35delG carrier frequency in the Middle East. Method: A systematic literature review of the PubMed, Google Scholar, Web of Science, and Science Direct databases was conducted for articles published before March 2019. The primary data of eligible studies including the number of samples, carrier frequency and so on were extracted. Results: Fourteen studies that involved 5,200 random controls from 15 populations of the Middle East were included and analyzed for the carrier frequency. The overall c.35delG carrier frequency was found to be 1.38% in the studied populations which is significantly lower than that identified in European populations, and also a west-to-east Middle Eastern gradient in the carrier frequency of c.35delG is suggested. Conclusion: This study shows the importance of establishing prevalence, based on the local population, for screening and diagnostic programs of live births.
keywords: 35delGGenetic counselingGJB2Hearing lossMiddle Eas
Next generation sequencing and genetics of hereditary hearing loss in the iranian population: New insights from a systematic review
No full textBackground: Hereditary hearing loss (HL) as a common disorder is genetically heterogeneous, which poses a challenge for clinical and molecular diagnosis. Next-generation sequencing (NGS) technologies have proven to be the best solution for mutational screening, even though it is not always conclusive. Here, we have reviewed the results of previously published data on HL mutations identified with NGS, as well as the efficiency of this technology in detecting HL in Iran. Methods: A systematic literature review of the PubMed, Google Scholar, Web of Science, and Science Direct databases were conducted for articles published before May 2019. The primary data of these studies, including the number of samples, mutation frequency and so on were extracted. Results: Seventy-five articles were reviewed, and 10 met our inclusion criteria. Totally 432 unrelated families were included and analyzed for the type and prevalence of the gene mutations and pathogenic variants were discovered in 34 non-syndromic HL (NSHL) genes. Altogether 237 different genetic mutations were detected. However, p. Gln1576Stop in PCDH15 was the most common mutation accounting for 1 of the populations studied. NGS platforms have yielded only a 47.1 molecular diagnosis rate for NSHL etiologies in the Iranian population, which is significantly lower than that identified in the other part of the Middle East. Conclusion: The results showed that NGS platforms can greatly assist and enhance HL diagnosis and improve molecular diagnostic outcome. However, researchers were unable to provide 53 of their Iranian cohort with a molecular diagnosis for their HL. It seems that many rare genes are responsible for the majority of HL in the Iranian cohort. Future explorative investigations utilizing NGS technologies, such as WES, into the Iranian population are warranted
GJB2-related hearing loss in central Iran: Review of the spectrum and frequency of gene mutations
Full text linkMutations in the GJB2 gene are a main cause of autosomal-recessive nonsyndromic hearing loss (ARNSHL) in many populations. Previous studies have estimated the average frequency of GJB2 mutations to be similar to 16% in Iran, but would vary among different ethnic groups. Here, we have taken together and reviewed results from our two previous publications and data from searching other published mutation reports to provide a comprehensive collection of data for GJB2 mutations and HL in central Iran. In all, 332 unrelated families were included and analyzed for the prevalence and type of the GJB2 gene mutations. In total, the frequency of GJB2 mutations was found to be 16% in the central provinces, which is significantly higher than those identified in southern populations of Iran. Also, c.35delG was the most frequent mutation in the related population. The present study suggests that mutations in the GJB2 gene, especially c.35delG, are important causes of HL in central Iran and can be used as a basis of genetic counseling and clinical guidelines in this region.
Keywords
Author Keywords:clinical guidelines; GJB2; Iranian population; nonsyndromic hearing los
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
An update on autosomal recessive hearing loss and loci involved in it
No full textHearing plays an important role in human development and childhood speech learning for the proper functioning and development of people in society. Hearing loss (HL) is one of the most abnormal disabilities that affect the human senses. This disability may be due to genetic or environmental factors or both. Congenital HL is a disorder that occurs in at least 1 in 1000 births. At least 42 genetic loci are associated with syndromes, while more than 163 are associated with nonsyndromic HL (NSHL), and no specific gene therapy treatment has yet been proposed. Investigate the types of genes involved in regulating hair cell adhesion "and evaluate functions such as intracellular transport, the release of neurotransmitters, ion homeostasis, and hair cell cytoskeleton, and whether defects in them can impair cochlear and inner ear function. " Can help diagnose and treat the disease through various methods, including gene therapy. Given the complex internal and external structures of the ear, nervous system, and auditory mechanisms, it is not surprising that abnormalities in hundreds of different genes may lead to HL. In recent years, with the increasing number of studies on genes involved in congenital HL, counseling and treatment options with the help of gene therapy have increased. In this study, we aimed to describe genes and proteins and their functions in NSHL in the inner ear for screening and diagnostic programs of live birth and classify the genes involved in this model of deafness to open the door to gene therapy. It is on these genes. We hope to develop new molecular and gene therapies for autosomal recessive NSHL
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Genetics of Hearing Loss in North Iran Population: An Update of Spectrum and Frequency of GJB2 Mutations
Full text linkDiagnosis of pre-lingual hearing loss (HL) is difficult owing to the high number of genes responsible. The most frequent cause of HL is DFNB1 due to mutations in the GJB2 gene. It represents up to 40% of HL cases in some populations. In Iran, it has previously been shown that DFNB1 accounts for 16-18% of cars but varies among different ethnic groups. Here, we reviewed results from our three previous publications and data from other published mutation reports to provide a comprehensive collection of data for GJB2 mutations and HL in northern Iran. In total, 903 unrelated families from six different provinces, viz., Gilan, Mazandaran, Golestan, Ghazvin, Semnan, and Tehran, were included and analyzed for the type and prevalence of GJB2 mutations. A total of 23 different genetic variants were detected from which 18 GJB2 mutations were identified. GJB2 mutations were 20.7% in the studied northern provinces, which was significantly higher than that reported in southern populations of Iran. Moreover, a gradient in the frequency of GJB2 mutations from north to south Iran was observed. c.35delG was the most common mutation, accounting for 58.4% of the cases studied. This study suggests that c.35delG mutation in GJB2 is the most important cause of HL in northern Iran.
Keywords
Author Keywords:Genetic counseling; Gap junction protein beta 2; Hearing loss; GJB2 insertion
KeyWords Plus:CONGENITAL DEAFNESS; PREVALENCE; FAMILIES; GENES; IDENTIFICATION; IMPAIRMENT; 35DELG; ARNSHL; SOUT
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