[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

[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

[Molecular investigation of mtDNA A1555G, A3243G and A7445G mutations among the non syndromic hearing loss cases in Fars, Iran]

Hearing loss is a sensorineural disorder occuring in 1 out of 500 births. It happens due to some genetic/environmental causes or both. More than 60% of cases are noninherited and 80% non syndromic with autosomal recessive inheritance. In the present study we investigated the frequency of mtDNA A1555G, A3243 and A7445G mutations among the patients in Fars province. Seventy two non syndromic hearing loss subjects were studied. DNA was extracted using standard phenol-chloroform method. The screening of the mitochondrial gene mutations were performed using PCR-RFLP procedure. Finally, the possible mutations were confirmed by direct sequencing. None of the A1555G, A3243G and A7445G mutations was detected in this study. However, destroying a MTTL1 restriction site for the investigation of A3243G mutation, revealed a G3316A with allelic variant of 1.4% in the deaf subjects. Our data indicated that the mitochondrial A1555G, A3243 and A7445G mutations have no role in auditory deficits in patients studied

[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

[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