[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

[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