[Study of three common mitochondrial mutations in Arab patients with nonsyndromic hearing loss in Khuzestan province, I.R.Iran]

Hearing Impairment [HI] is the most prevalent neurosensory disorder occurs in 1/1000 newborn. The majority of hearing deficiencies are of genetic origin. About%0-2 of the genetic HI cases are due to mutations in mitochondrial genes. In the present study we investigated the frequency of 3 mtDNA A1555G, A3243G and A7445G mutation of 62 patients with nonsyndromic hearing loss in Khuzestan province. In this descriptive study, we investigated the presence of three mitochondrial mutations; A1555G, A3243G and A7445G in 62 Arab subjects with autosomal recessive non syndromic hearing loss in Khuzestan province. DNA was extracted using standard phenol -chloroform method. The screening of the mitochondrial gene mutations was performed by PCR-RFLP procedure.The possible mutations were confirmed by direct sequencing. None of the investigated mutations; A1555G, A3243G and A7445G were detected in this study. However PCR-RFLP revealed two mutations; G3316A, A7445C in 2 deaf subjects studied. This study is shown that mtDNA mutations consist of G3316A and A7445C are responsible for few of ARNSHL in sample studied and none of the A1555G, A3243G and A7445G mutations are responsible for ARNSHL in this population. The data presented here will improve the genetic counseling of hearing impaired patients in Khuzestan province

[Factor XIIIA-V34L and factor XIIIB-H95R gene polymorphisms in Shahrekord, 2010, I.R.Iran]

Some of the inherited coagulation factor polymorphisms have been related to the pathogenesis of venous thromboembolism and other adverse outcomes. As there are limited data on the prevalence of these polymorphisms in Iranian populations this study aimed to assess two factor XIII polymorphisms, FXIIIA-V34L and FXIIIB-H95R, in healthy individuals. In this cross sectional study 150 healthy blood donors from Shahrekord, Iran with no history of venous thromboembolism were recruited to the study. Genotyping from EDTA taken venous blood for the above polymorphisms was under taken by PCR - RFLP. Fifty one [34%] of participants were heterozygous for VL and 7[4.67%] were homozygous LL. 26 [17.33%] and 1[0.67%] were heterozygous and homozygous for RH and RR of FXIIIB respectively. 48.67% of the study population carried at least one of the above polymorphisms and there was no carrier of both as homozygous. The prevalence of these FXIII polymorphisms in healthy subjects is somehow similar to previously published data in Caucasian populations, but quite different than limited existing data from China and other ethnic groups. Such findings could be relevant to the ethnic similarities and differences

[Study of deafness associated with DFNB59 gene [Pejvakin] mutation in Fars province]

Hearing loss is the most frequent sensory disorder affecting 1 in 500 neonates with more than 50% of inherited cases. This trait is a very heterogeneous disorder and happens due to genetic or environmental causes or both. More than 46 genes may be involved in non-syndromic hearing loss. Recently, DFNB 59 gene has been shown to cause deafness in some Iranian populations. The aim of this study was to determine the role of DFNB 59 gene mutations causing deafness in a group of 130 deaf pupils in Fars province. This descriptive-laboratory based study investigated the frequency of DFNB59 gene mutations using PCR-SSCP/HA strategy. Two different DFNB59 polymorphism including 874G>A and 793C>G were found in 1 and 9 of 130 patients studied respectively. However, no DFNB59 mutation was identified. The results of this study shows that the association of DFNB59 mutations with deafness in Fars province is very low

[DFNB59 gene mutations and its association with deafness in schoolchildren in kohgilooyeh and Boyerahmad province]

Hearing loss is a common disease affecting millions of people worldwide. Hearing loss can be caused due to genetic or environmental factors or even both. The genetic of hearing defect is highly heterogeneous and more than 100 genes are predicted to cause this disorder in humans. A newly identified gene [DFNB59] has been shown to cause deafness in some populations. Here we report mutation analysis for DFNB59 gene in 88 genetic non-syndromic hearing loss subjects. In this descriptive-lab based study which was conducted at the Cellular and Molecular Research Center of Shahrekord University of Medical Sciences, DNA was extracted from the peripheral blood samples using standard phenol chloroform procedure. Mutation analysis for DFNB59 gene was performed using PCR-SSCP/HA protocol. The suspected DFNB59 which was detected as shifted bands on PAGE were then confirmed by direct sequencing strategy. Two DFNB59 polymorphisms including c.793C>G and c.793C>T were detected in 8 and 1 deaf subjects respectively. We conclude that there is no association between DFNB59 mutations and deafness in the studied patients in the region

[Frequency of 35delG mutation in GJB2 gene in non-syndromic prelingual hearing loss in 3 provinces of Iran]

Hearing loss is the most common inherited sensory disorder. At least 50% of hearing loss is inherited and about half of the genetic hearing loss is autosomal recessive non-syndromic. Mutations in GJB2 gene is the most frequent cause of autosomal recessive non-syndromic hearing loss. A single 35delG mutation is the most common allelic variant of GJB2 in most parts of the world. The aim of this study was to determine the rate of 35delG mutation in non-syndromic prelingual hearing loss in 3 provinces of Iran. In this descriptive experimental study, 240 cases with autosomal recessive non-syndromic hearing loss in 3 provinces of Iran, including Azarbaijan Sharghi [97 cases], Chaharmahal va Bakhtiari [98 cases] and Gilan [45 cases] were screened for 35delG mutation in the GJB2 gene. Blood samples [5 ml] were taken for genomic DNA extraction. The mutation was screened using Nested-PCR method and the positive results were confirmed by subsequent direct sequencing. Results of this study showed that from 240 studied patients [480 chromosomes], 35delG mutation was found in 58 chromosomes [24 patients were homozygote and 10 patients were heterozygote]. The frequency of 35delG mutation was 12.08%, including 18.04% in Azarbaijan Sharghi, 3.06% in Chaharmahal va Bakhtiari and 18.88% in Gilan province. Prevalence of 35delG mutation in Chaharmahal va Bakhtiari population was lower than other provinces studied. These results indicate that the other genes or mutations could result in autosomal recessive non-syndromic hearing loss in Chaharmahal va Bakhtiari population. However, as we found a low rate of 35delG in the populations studied, the cause of deafness remains to be detected in other loci or genes

[DFNB59 gene mutations screening in non syndromic deaf subjects in Chaharmahal va Bakhtiari province]

The incidence of pre-lingual deafness is about 1 in 1000 neonates from which more than 60% of cases are inherited. Deafness is a heterogeneous disorder and may be due to genetic or environmental cause or both. Mutations in the DFNB59 gene encoding pejvakin protein has been very recently shown to cause neural deafness. In the present study, we have conducted type and frequency of the DFNB59 gene mutations in a cohort of 100 non syndromic deaf subjects in Chaharmahal va Bakhtiari province. In this descriptive-lab based study we investigated the frequency of DFNB59 gene mutations in the entire coding exons of the gene. DNA was extracted from the peripheral blood samples following the standard phenol chloroform procedure. DFNB59 gene mutations were investigated using PCR-SSCP/ Heteroduplex Analysis [HA]. The results of PCRSSCP/HA were confirmed by sequencing of exon 7, nested PCR and PCR-RFLP of 3 known DFNB59 mutations. Altogether 3 different gene polymorphisms [793C>G, 793C>T and 874G>A] and one mutation [988delG] were detected in 7, 5, 2 and 1 subjects respectively. Based on our data from the present study and previous study, we conclude that DFNB59 gene mutations have a very low contribution to deafness in patients in Chaharmahal va Bakhtiari province and are not of great clinical importance in this region