جستجوی مقالات مرتبط با کلیدواژه "ژن gjb2" در نشریات گروه "پزشکی"

Deafness (HL) is the most common sensorineural disorder. The frequency of hearing impairment in the world is one in every 500 newborns. However, in Iran, due to the high rate of consanguineous marriages, this amount is estimated to be two to three times higher. So far, more than 120 genes causing non-syndromic deafness (NSHL) have been known in the world. Among these, GJB2 gene mutations are the most common cause of autosomal recessive NSHL. The aim of this research was to determine and investigate the frequency and spectrum of GJB2 gene mutations in the non-syndromic deaf population of Semnan province.

The present practical study was conducted in 2021 on 50 patients with non-syndromic hearing loss from 50 unrelated families. First, the very common 35delG mutation was screened by allele-specific polymerase chain reaction (ASPCR). Then, in order to identify other mutations of the GJB2 gene, patients who were negative or heterozygous for the 35delG mutation were analyzed by trench sequencing for all exonic regions and splicing sites of the GJB2 gene. The collected data were analyzed using descriptive statistical tests.

In the present study, 100 chromosomes (50 patients) were examined. 12 chromosomes (12%) indicated mutation in GJB2 gene. Among these, the share of each of the identified mutations 35delG, IVS1+1G>A and c.94C>T: p. Arg32Cys in the deaf population of Semnan province, respectively; 7, 4 and 1 percent. Thus, the common 35delG mutation includes 58.34% of all identified mutations. Also, unlike other populations studied in Iran, the IVS1+1G>A splice site mutation had a relatively high prevalence in the deaf population of Semnan province.

The results of the present study indicated that GJB2 gene mutations comprised only 12% of mutations causing hearing loss in the deaf population of Semnan province, which emphasizes the importance of using next generation sequencing techniques to identify other genes causing hereditary hearing loss in this population. Such an approach will significantly aid in carrying out genetic counseling, prenatal diagnosis and clinical management of hearing loss in Semnan province.

Non-syndromic hearing loss is a genetically heterogeneous disorder. Mutation in GJB2 gene is a major cause of non-syndromic hearing loss in many countries. The aim of this study was to evaluate GJB2 mutations in 31 individuals with non-syndromic hearing loss in Guilan province.

In this descriptive cross-sectional study, blood samples were collected from 31 individuals with non-syndromic hearing loss in Rasht and Bandar Anzali cities. After DNA isolation, GJB2 gene was amplified by PCR method and underwent sequencing.

In this study, three mutations were determined in 18 individuals with hearing loss. 35delG mutation had the highest frequency (48.38%) in individuals with hearing loss as homozygote (in 14 individuals) and heterozygote (in 2 individuals). A patient with heterozygosity in V153I mutation and a patient with compound heterozygosity in 35delG/G200R mutation were determined. 

It appears that 35delG mutation is a common mutation in GJB2 gene in individuals with non-syndromic hearing loss in Guilan province

Deafness is the most common sensory disorder in humans which is highly heterogeneous. Among its various types، autosomal recessive non-syndromic hearing loss (ARNSHL) is responsible for 80% of pre-speech congenital cases of hearing loss. The purpose of this study was to investigate the genetic linkage of DFNB4 locus in hearing impaired families in Hormozgan. Ten deaf large families in the Hormozgan province were selected. A hearing impaired person was selected from each family tree and sequence of the GJB2 gene in regards of coding regions'' mutations was investigated using sequencing method. STR markers of DFNB4 locus in families with no mutation in GJB2 were amplified using PCR and after determining the type alleles، they were analyzed for linkage. In one among the ten studied families، GJB2 mutation was observed. The nine other families were entered for linkage studies and no linkage was found in the said families. Due to the high heterogeneity of loci associated with ARNSHL، other factors may be involved in the cause of deafness in families، without mutations in the GJB2 gene and the investigated locus. Therefore it is recommended to study other loci and more families in this matter.

Mutations in GJB2 gene is the most common cause of autosomal recessive non-syndromic hearing loss in many populations. The aim of this study was to determine the frequency of 35delG, 167delT, M34T, 235delC mutations in West Azarbaijan population. 129 patients from 96 families were studied. Mutations were detected using ASO-PCR and PCR-RFLP methods. Totally, 65.89% of cases were sporadic and the remaining (34.11%) were familial. Six out of 8 cases with 35delG mutation and one case with 235delC mutation were offspring of consanguineous union. Mutations of 35delG were detected in 8 families. 167delT and M34T mutations were not found but 235delC was detected only in one family. On the other hand, 13 out of 258 chromosomes had 35delG mutations. Five patients were homozygous and 3 were heterozygous for 35delG mutation. It means that, in 5.04% of the patients the major reason for hearing loss was 35delG mutation. One out of 258 (0.39%) chromosomes had heterozygous 235delC mutation. It can be concluded that the other genes or mutations could result in autosomal recessive non-syndromic hearing loss in West Azerbaijani population.

Hearing loss is the most common sensory neural defect in humans, affecting 1 in 1000 neonates, with over half of these cases predicted to be hereditary in nature. Most hereditary hearing loss is inherited in a recessive fashion, accounting for approximately 80 % of non-syndromic hearing loss (NSHL). Mutations in GJB2 gene are major cause of inherited deafness in the European and American populations. To date, more than 90 mutations have been reported in this gene. Although most of these mutations are rare but 35delG mutation is the most common deafness causing allelic variant of GJB2 in most parts of the world.

In this project, 120 probands from 120 families with ARNSHL in Yazd Province were studied. Mutations Screening of GJB2 was performed by Amplification Refractory Mutation System (ARMS)-PCR for detection of 35delG and then all samples excluding 35delG homozygote were analyzed by DHPLC and Direct Sequencing.

GJB2-related deafness was present in 7.5% of this population. We identified 4 mutations (35delG, 312del14, 314del14 and 167delT) and 4 polymorphisms (V153I, V27I, E114G and R127H) in this study.

Prevalence of GJB2 mutations in this population was lower than American and European populations, and also other provinces of Iran. Interestingly, 312del14 rather than 35delG was the most common mutation found in the population under study. 56.25 % of GJB2 mutant alleles carried 312del14 mutation. To date, this frequency has not been reported in any of the world populations.