Mutations in GJB2 as Major Causes of Autosomal Recessive Non-Syndromic Hearing Loss: First Report of c.299-300delAT Mutation in Kurdish Population of Iran

BACKGROUND AND OBJECTIVES: Autosomal recessive non-syndromic hearing loss (ARNSHL) with genetic origin is common (1/2000 births). ARNSHL can be associated with mutations in gap junction protein beta 2 (GJB2). To this end, this cohort investigation aimed to find the contribution of GJB2 gene mutations with the genotype-phenotype correlations in 45 ARNSHL cases in the Kurdish population. SUBJECTS AND METHODS: Genomic DNA was extracted from a total of 45 ARNSHL families. The linkage analysis with 3 short tandem repeat markers linked to GJB2 was performed on 45 ARNSHL families. Only 9 of these families were linked to the DFNB1 locus. All the 45 families who took part were sequenced for confirmation linkage analysis (to perform a large project). RESULTS: A total of three different mutations were determined. Two of which [c.35delG and c.-23+1G>A (IVS1+1G>A)] were previously reported but (c.299-300delAT) mutation was novel in the Kurdish population. The homozygous pathogenic mutations of GJB2 gene was observed in nine out of the 45 families (20%), also heterozygous genotype (c.35delG/N)+(c.-23+1G>A/c.-23+1G>A) were observed in 4/45 families (8.8%). The degree of hearing loss (HL) in patients with other mutations was less severe than patients with c.35delG homozygous mutation (p < 0.001). CONCLUSIONS: Our data suggest that GJB2 mutations constitute 20% of the etiology of ARNSHL in Iran; moreover, the c.35delG mutation is the most common HL cause in the Kurdish population. Therefore, these mutations should be included in the molecular testing of HL in this population.

Effect of oxidized low density lipoprotein on the expression of Runx2 and SPARC genes in vascular smooth muscle cells

Vascular calcification is an important stage in atherosclerosis. During this stage, vascular smooth muscle cells [VSMC] synthesize many osteogenic factors such as osteonectin [encoded by SPARC]. Oxidative stress plays a critical role in atherosclerosis progression, and its accumulation in the vascular wall stimulates the development of atherosclerosis and vascular calcification. The osteonectin overexpression has been observed in the arterial wall during the course of atherosclerosis. However, the regulatory mechanism of oxidized low density lipoprotein [oxLDL]-mediated vascular calcification remains to be clarified. The aim of this study was to investigate the effect of oxLDL on the osteonectin gene expression through the Runx2 transcription factor. In this experimental study, VSMC were cultured in F-12K media and then treated with oxLDL. The expression of Runx2 and osteonectin genes was determined by real-time PCR method. Protein levels were investigated by the western blotting technique. The Runx2 gene was knocked down using siRNA in order to determine whether Runx2 regulates the osteonectin expression in VSMC induced by oxLDL. Then transfected cells were treated with oxLDL, and the expression levels of Runx2 and osteonectin were determined again. oxLDL was found to increase Runx2 and osteonectin gene expression [4.8 +/- 0.47- and 9.2 +/- 1.96-fold, respectively] after 48 h. Western blotting analysis confirmed the induced levels of Runx2 and osteonectin proteins. However, oxLDL-induced osteonectin expression was not observed to be blocked by Runx2 knockdown. The up-regulation of osteonectin by oxLDL is independent of Runx2, and it may be mediated by other transcription factors

Identification of Xq22.1-23 as a region linked with hereditary recurrent spontaneous abortion in a family

Recurrent spontaneous abortion [RSA] is one of the most common health complications with a strong genetic component. Several genetic disorders were identified as etiological factors of hereditary X linked RSA. However, more genetic factors remain to be identified. In this study we performed linkage analysis on a large X linked RSA pedigree to find a novel susceptibility locus for RSA. A linkage scan using 11 microsatellites was performed in 27 members of a large pedigree of hereditary X-linked RSA. Two point parametric Linkage was performed using Superlink v 1.6 program. Evidence of linkage was observed to markers at Xq23, DXS7133 and at Xq22.1 DXS101, with LOD score of 3.12 and 1.60, respectively. Identified locus in this study may carry a responsible gene in RSA. Narrowing down of this region may leads to identification of this gene

Compound Heterozygosity for Two Novel SLC26A4 Mutations in a Large Iranian Pedigree with Pendred Syndrome

OBJECTIVES: The aim of this study was to detect the genetic cause of deafness in a large Iranian family. Due to the importance of SLC26A4 in causing hearing loss, information about the gene mutations can be beneficial in molecular detection and management of deaf patients. METHODS: We investigated the genetic etiology in a large consanguineous family with 9 deaf patients from Fars province of Iran with no GJB2 mutations. Initially, linkage analysis was performed by four DFNB4 short tandem repeat markers. The result showed linkage to DFNB4 locus. Following that, DNA sequencing of all 21 exons, their adjacent intronic sequences and the promoter of SLC26A4 was carried out for mutation detection. RESULTS: Two novel mutations (c.863-864insT and c.881-882delAC) were identified in exon 7 of the gene, in both homozygous and compound heterozygous state in patients. CONCLUSION: Our results supported the importance of the SLC26A4 mutations in the etiology of hearing loss among the Iranian patients and therefore its mutation screening should be considered after GJB2 in the molecular diagnostics of hearing loss, especially when enlarged vestibular aqueduct or goiter is detected.

Bilateral dislocation of temporomandibular joint induced by haloperidol following suicide attempt: a case report

Drug induced dystonic reactions are among common presentations of patients in emergency departments, and typically occur with antidopaminergic agents as their extra-pyramidal side effects. Dystonic reactions usually occur within the first few hours or days after commencing a drug or dose increase. Unlike other extra-pyramidal side effects, a patient may experience acute dystonic reactions [ADRs] with the administration of just a single dose. Oromandibular dystonia is a subtype of dystonia which can present with perioral manifestations. In extreme cases, it can lead to temporomandibular dislocation. Haloperidol, as a high potent typical antipsychotic drug, can induce dystonia with blocking D[2] dopamine receptors. The present paper reports a case of bilateral dislocation of temporomandibular joint following ingestion of haloperidol in a suicidal attempt in a 17 years old girl