Background: Hemophilia A is an X-linked bleeding disorder caused by heterogenous mutations in factor VIII gene that encodes coagulation factor VIII (F8) protein. Due to the high heterogeneity of mutations, large size (186 kb) and structural complexity of the F8 gene, direct mutation analysis is costly and time consuming. Alternatively, linkage analysis using informative polymorphic markers such as single nucleotide polymorphism (SNP) markers has been introduced as a rapid and cost effective method for hemophilia A carrier detection in families with an affected individual. Several SNP markers associated with the F8 gene region have been studied.

Materials and Methods: In this exprimental study, the characteristics of A/T SNP (rs4898352) as an informative marker located in intron 18 of F8 gene region was investigated in Isfahanin population. rs4898352 marker was genotyped using tetra primer ARMS PCR method followed by agarose gel electrophoresis in 140 unrelated control healthy females in mentioned population. New primers were designed for rs4898352 marker using the oligo 7 software. The allele frequency, degree of heterozygosity and Hardy-Weinberg equilibrium were estimated by use of Genepop program. The polymorphism information content (PIC) value was estimated using the Powermarker software.

Results:  The results showed that the allele frequency of rs4898352 polymorphism for A and T alleles was 0.482 and 0.518, respectively. The observed heterozigosity rate was 60%. Analysis of Hardy-Weinberg Equilibrium demonstrated that the Isfahan population was in equilibrium (p>0.05) for rs4898352 marker. Moreover, analysis of PIC value revealed that this marker could be considered as a highly informative marker in the mentioned population.

Conclusion: Together, the data suggested that rs4898352 could be introduced as an informative marker for molecular diagnosis of hemophilia A in Isfahan Population

Background: Hearing loss is a common sensory impairment in humans which half of its causes are genetic reasons. Genetic hearing loss can be divided into the two types of syndromic and non-syndromic, which 80% of non-syndromic cases is Autosomal Recessive Non-Syndromic Hearing Loss. The aim of the present research is to determine the contribution of DFNB2 locus (MYO7A gene) in causing an autosomal recessive hearing loss in the one group of the deaf families of Khuzestan province.

Materials and Methods: This study was conducted on 26 families with autosomal recessive hearing loss (with 4 patients) and negative for GJB2 mutations in Khuzestan province. 22 families suffered from ARNSHL and 4 families suffered from Usher syndrome. Linkage analysis was performed by using STR (Short Tandem Repeat) markers related to DFNB2 locus. Each family’s genotype was determined by PCR-PAGE method. Furthermore, haplotypes drawing and LOD score calculations were performed.

Results: From 26 families with hearing loss participating in this research, following genetic linkage analysis and haplotypes drawing, two families (7.7% of the families) showed linkage to DFNB2 locus. One family (4.5%) suffered from ARNSHL and another family suffered from Usher syndrome.

Conclusion: The results of the present research show that the contribution of DFNB2 locus in causing hearing loss in the population of Khuzestan province was similar to other studies conducted in Iran and this locus with other important loci should be considered to check in the hearing loss panel.

Abstract

Background: Hearing loss (HL) is the most common congenital defect in humans. One or two in thousand newborn babies have prelingual hearing loss. Autosomal recessive non-syndromic hearing loss (ARNSHL) is the most common form of hereditary deafness. Hearing loss is more common in the developing countries which is due to genetic and environmental (cultural -health factors) reasons. HL has a wide range of clinical demonstrations including: congenital or late onset, conductive or sensory-neural, syndromic or non-syndromic hearing loss. The goal of this project is to determine the portion of the DFNB21 (TECTA) in ARNSHL in families with negative GJB2 gene in Khuzestan province.

Materials and Methods: We studied 21 families with ARNSHL with at least 4 patients and negative for GJB2 mutations from Khuzestan province. Genetic linkage analysis was performed using STR markers linked to DFNB21 locus.

Results: Following genetic linkage analysis and haplotyping, out of 21 families with ARNSHL, one family showed linkage to the DFNB21 (TECTA) locus.

Conclusion: The results of this project confirm other studies in Iran and give insight into the most common loci causing ARNSHL in Iran which could be helpful in research and clinic.