[Informativeness of D7S2456 marker for molecular diagnosis of autosomal recessive non syndromic hearing loss in five Iranian ethnic groups]

SLC26A4 gene mutations after GJB2 mutations are the second currently identifiable genetic cause of autosomal recessive non syndromic hearing loss [ARNSHL] which currently is used in molecular diagnosis of ARNSHL. Several potential STR markers related to this region have been reported .This study was carried out to identity the informativeness of D7S2456 CA repeat STR marker in SLC26A4 gene region in five ethnic groups of the Iranian population. In this descriptive study, The locus was genotyped in 165 unrelated healthy individuals of five different ethnics including Fars, Azari, Turkmen, Gilaki and Arabs ethnic groups using polymerase chain reaction [PCR] followed by polyacrylamide gel electrophoresis [PAGE] and fluorescent capillary electrophoresis. Data was analyzed by Gene Marker HID Human STR Identity software, Gene Pop program and Microsatellite Tools software. Analysis of the allelic frequency revealed the presence of 9 alleles for D7S2456 marker in the Iranian population, which allele 5 at the D7S2456 locus with 55% frequency was the most frequent. The most frequent heterozygosity with rate of 81.8% belongs to Azari ethnic group. Analysis of deviations from Hardy-Weinberg equilibrium demonstrated that all the ethnics except Fars were in equilibrium for D7S2456 locus. D7S2456 marker is a moderately informative marker in Iranian ethnic population [PIC value within 0.44 and 0.7]. D7S2456 is a moderately informative marker in diagnosis of SLC26A4 based autosomal recessive non syndromic hearing loss in Iranian population by linkage analysis

[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

[Frequency of the common mitochondrial DNA [mtDNA] mutations in non-syndromic hearing impairment in southwest subpopulations of Iran]

Although, most hereditary non-syndromic hearing impairment [NSHI] is due to mutation in nuclear genes, role of mtDNA mutations in causing deafness becoming much more clear in recent years. The aim of the present study was to screen the A1555G, C1494T, A3243G and A7445G mutations in non-syndromic hearing impairment patients in two provinces of southwest of Iran. In this descriptive laboratory study, 150 subjects with acquired and prelingual autosomal recessive NSHI from Chaharmahal va Bakhtiari province and 46 unrelated probands with postlingual NSHI from Bushehr province [negative for GJB2 mutations] were screened for the presence of the common mtDNA mutations using PCR-RFLP method that followed by direct sequencing for confirming the observed mtDNA mutations. None of these mutations was found in subjects with acquired and prelingual autosomal recessive NSHI from Chaharmahal va Bakhtiari province, but mutation A1555G with frequency of 4.35% was found in postlingual NSHI patients in Bushehr province. This investigation shows that apparently, mtDNA mutations play a more significant role role in the etiology of postlingual NSHI in comparison with prelingual NSHI

[Study of I405V polymorphism of cholesterol ester transfer protein gene in efficacy of statins on plasma level of high density lipoprotein cholesterol]

Cholesterol ester transfer protein [CETP] plays a pivotal role in high density lipoprotein [HDL] metabolism and reverse cholesterol transport [RCT] pathway. CETP gene variants such as I405V that affect HDL cholesterol directly modulate CETP gene transcriptional activity. This study aims to determine influence of I405V polymorphism of CETP in statin effects with regard to plasma HDL cholesterol levels. In this descriptive analytical study, 196 adult patients with LDL-C more than 120 mg/dL were divided into two groups based on the lovastatin and atorvastatin using. There was no significant difference in demographic characteristics between two groups. Lipid profile was measured in all subjects before and after treatment and I405V polymorphism of CETP promoter was studied using polymerase chain reaction/restriction fragment length polymorphism method [PCR-RFLP]. Data were compared using paired t-test and ANOVA. Cholesterol was decreased and HDL was increased in VV genotype more than other genotypes by lovastatin and atorvastatin [P<0.05] but ApoA1 was increased in II genotype. ApoA1 also was increased in IV by atorvastatin despite of lower HDL. Lovastatin and specially atorvastatin increased ApoA1 in HDL particles in II genotype more than other genotypes. Therefore, treatment with lovastatin and atorvastatin is more effective in patients with II genotype for preventing of CAD

[Association of [Ile462Val in genetic polymorphisms CYP1A1] and uterine leiomyoma risk in women in Charmahal va Bakhtiari, I.R. Iran]

Uterine leiomyoma is a benign solid tumor of smooth muscle and the most common type of gynecological tumor. It occurs in approximately 25-30% of women over 30 years old. Studies have shown that the growth of uterine leiomyma was related to estrogen, cousidering the effect of CYP1A1 gene in estrogen metabolism, this study was done to evaluate the association of CYP1A1 [Ile462Val] polymorphisms with uterine leiomyoma in Charmahal va Bakhtiari women. In this case - control study, 156 non menopause women with the age ranges of 17-57, with clinically diagnosed uterine leiomyoma and 151 healthy normal subjects were investigated. The Ile462Val [AG] Polymorphism between the two groups [P=0.306]. The results of this study demonstrated that the CYP1A1Ile462Val polymorphism was not correlated with an increased risk of uterine leiomyoma in the study population

Genetic linkage analysis of 15 DFNB loci in a group of Iranian families with autosomal recessive hearing loss

Hearing loss [HL] is the most frequent sensory birth defect in humans. Autosomal recessive non-syndromic HL [ARNSHL] is the most common type of hereditary HL. It is extremely heterogeneous and over 70 loci [known as DFNB] have been identified. This study was launched to determine the relative contribution of more frequent loci in a cohort of ARNSHL families. Thirty-seven Iranian families including 36 ARNSHL families and 1 family with Pendred syndrome each with >/= 4 affected individuals, from seven provinces of Iran, were ascertained. DFNB1 contribution was initially studied by DNA sequencing of GJB2 and linkage analysis using the relative STR markers. The excluded families were then subjected to homozygosity mapping for fifteen ARNSHL loci. Sixteen families were found to be linked to seven different known loci, including DFNB1 [6 families], DFNB4 [3 families +1 family with Pendred syndrome], DFNB63 [2 families], DFNB2 [1 family], DFNB7/11 [1 family], DFNB9 [1 family] and DFNB21 [1 family]. DNA sequencing of the corresponding genes is in progress to identify the pathogenic mutations. The genetic causes were clarified in 43.2% of the studied families, giving an overview of the causes of ARNSHL in Iran. DFNB4 is ranked second after DFNB1 in the studied cohort. More genetic and epigenetic investigations will have to be done to reveal the causes in the remaining families

[Detection of A1430G mutation in SCN1A gene in a patient affected by GEFS-like epilepsy in Chaharmahal va Bakhtiari province]

Background and aim: SCN1A gene encodes for neuronal voltage-gated sodium-channel ?-subunit. Mutations in this gene are the major cause of severe myoclonic epilepsy of infancy [Dravet syndrome] and generalized epilepsy with febrile seizures plus [GEFS[+]]. GEFS[+] is a heritable benign type of epilepsy associated with febrile seizures which belongs to Idiopathic Generalized Epilepsies with a marked clinical and genetic heterogeneity. The main objective of this research is screening of mutations in scn1a gene in patients affected by GEFS[+] and Idiopathic Generalized Epilepsy [IGE]

Methods: Genetic counseling was carried out with 30 patients and their family. Peripheral blood samples were collected from patients and DNA was extracted using salting out method. Standard PCR on 16[th]-26[th] exons of scn1a gene was optimized by employment of specific primers. PCR products were analyzed by SSCP in denaturant condition and sequenced in the next step

Results: Results showed a 4289c>g missense mutation in one patient affected by idiopathic generalized epilepsy. This mutation changes the alanine residue in 1430 position to glycine [A1430G]

Conclusion: More studies are needed to identify the direct role of this mutation in pathogenesis, however, heterozygotic genotype of this mutation is consistent with dominant feature of inheritance of Epilepsy

[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

[Study of-629C/A polymorphism of cholesteryl ester transfer protein gene in statin effects on plasma high density lipoprotein cholesterol level]

Cholesteryl ester transfer protein [CETP] plays pivotal role in HDL metabolism and in reverse cholesterol transport [RCT] pathway. CETP gene variants such as-629C/A that affect HDL cholesterol directly, modulates CETP gene transcriptional activity. This study was aimed to determine influence of-629C/A polymorphism of CETP in statin effects with regard to plasma HDL cholesterol levels. In this descriptive-analytical study, 196 adult patients with LDL-C more than 120mg/dL were divided into two groups base on lovastatin and atorvastatin using. Lipid profile was measured in all subjects before and after treatment and-629C/A polymorphism of CETP promoter was studied using polymerase chain reaction/restriction fragment length polymorphism method. Data were compared with paired t-test and ANOVA in SPSS software. Cholesterol was decreased and HDL was increased in AA genotype more than other genotypes by lovastatin, but ApoA1 was increased in CC genotype. ApoA1 also was increased in CC genotype more than AA or AC genotypes by atorvastatin. In CC genotype, lovastatin and specially atorvastatin increased ApoA1 in HDL particles more than other genotypes. Therefore, treatment with lovastatin and atorvastatin is more effective in patients with CC genotype for raising HDL particles activity

[Mutation screening of GJB2 and GJB6 and genetic linkage study of three prevalent DFNB loci in Iranian families with autosomal recessive non-syndromic hearing loss]

The incidence of prelingual hearing loss [HL] is about 1 in 1000 neonates of which, more than 60% of cases are inherited. Non-syndromic HL [NSHL] is extremely heterogeneous: more than 100 loci have been identified. The most common form of NSHL is the autosomal recessive form [ARNSHL]. Here, we have investigated CX26 [GJB2] and CX30 [GJB6] gene mutation and linkage analysis of 3 known loci in Iranian families. A cohort of 36 big ARNSHL pedigrees from 7 provinces of Iran was investigated. All of the families were examined for the presence of GJB2 and GJB6 [del D13S1830 and del D13S1854] mutations using direct sequencing and multiplex PCR, respectively. The negative mutations pedigrees for the above-mentioned mutations, were then tested for the linkage to the 3 known loci, including DFNB3[MYO7A], DFNB4[SLC26A4] and DFNB7/11[TMC1], using STR markers and conventional PCR and PAGE. Six families had GJB2 mutations. No GJB6 mutation was found. Totally, 3 families showed linkage to DFNB4 and 1 family was linked to DFNB7/11. DFNB1 [GJB2] and DFNB4 are the main causes of ARNSHL in our study samples and GJB6 mutations are apparently absent in the Iranian population

[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

[Study of LDL receptor gene mutations in patients with familial hypercholesterolemia in Chaharmahal va Bakhtiari province]

Familial hypercholesterolemia is an autosomal dominant inherited disorder, characterized by increased level of low-density lipoprotein cholesterol and lipid accumulation in tendons and arteries. It can cause premature atherosclerosis and increased risk of coronary heart disease [CHD]. Familial hypercholesterolemia is caused mainly by mutations in low-density lipoprotein receptor [LDLR] gene. The aim of this study was to analyze the LDLR gene mutations in a group of patients from Chaharmahal va Bakhtiari province. In this descriptive-lab based study, 57 suspected FH patients were screened for mutations in promoter and exons 1,3,5,11,13,15,16,17 and 18 of LDLR gene using PCR-SSCP strategy. Two different LDLR gene variations, including heterozygote mutation 283T>A and polymorphism 1959T>C, were identified in 1 and 9 FH Families studied, respectively. We conclude that LDLR gene mutation may not be the major cause of FH in the population studied and the cause of FH in Chaharmahal va Bakhtiari province 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

Molecular pathology of 6 novel GJB2 allelic variants detected in familial and sporadic Iranian non syndromic hearing loss cases

Mutations of GJB2 gene encoding connexion 26 are the most common cause of hearing loss in many populations. A very wide spectrum of GJB2 gene mutations associated with hearing loss have been detected but pathogenic role has been tested only for a part of them. In this study, we have provided genetic evidence on the pathogenicity of our previously reported novel GJB2 allelic variants. The pathogenic role of GJB2 allelic variants were assessed using co segregation of each allelic variant with hearing loss in family members, absence of the allelic variants in control populations, coexistence with a second GJB2 mutation, nature of the amino acid substitution and evolutionary conservation of the appropriate amino acid. The GJB2 allelic variants including 363delC, 327delGGinsA, H16R and G200R have been co segregated with autosomal recessive non syndromic hearing loss in five families and are not found in control subjects. The G130V and K102Q were found in heterozygous state in two deaf individuals. G130V results in an exchange a residue highly conserved among all the connexins but was found with a rate of 1% in control subjects and K102Q results in an exchange a residue not conserved among all the connexins and not identified in control subjects. We conclude that, 363delC, 327delGGinsA, H16R and G200R may be pathogenic. However, the pathogenicity and inheritance of K102Q and G130V can not be assessed clearly and remains to be identified

Familial and sporadic GJB2-related deafness in Iran: review of gene mutations

Mutations in the GJB2 gene encoding connexin 26 protein, are the main cause for autosomal recessive and sporadic non syndromic hearing loss in many populations. Here, we have taken together and reviewed results from our six previous publications, our unpublished data from ten Iranian provinces, as well as data from two previous mutation reports to provide a comprehensive collection of data for GJB2 mutations and deafness in Iran. In all, 1095 hearing impaired students and their deaf siblings from 890 families in 10 provinces of Iran were studied. The prevalence and type of the GJB2 gene mutations were investigated using nested PCR pre screening strategy and direct sequencing of the coding exon of the gene. Altogether 31 different genetic variants were detected from which 17 GJB2 mutations were identified. GJB2 mutations were found in 14.6% of deaf families [18.29% of familial and 12.7% of sporadic cases]. We found GJB2 mutations in both alleles in 78% of GJB2 mutations chromosomes. However, 35delG mutation was the most common GJB2 mutation accounting for 74.5% of the mutations in populations studied. Our data indicated that a specific combination of GJB2 mutations types and frequencies was presented in different populations of Iran. These results also highlight the importance of GJB2 mutations in development of hearing loss in familial and sporadic deaf families in different parts of the country and can be used as a basis of genetic counseling and clinical guideline in Iran