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Shirin G.,Pasteur Institute of Iran | Shirin G.,Tehran University of Medical Sciences | Maryam A.,Pasteur Institute of Iran | Maryam A.,Tehran University of Medical Sciences | And 4 more authors.
Clinical Laboratory | Year: 2016

Background: Non-syndromic autosomal recessive intellectual disability (NS-ARID) is a heterogeneous neurodevel opmental disease. More research is needed to study the NS-ARID genes. Using STR markers linked to a specific gene, we can perform homozygosity mapping and prenatal diagnosis. One approach to investigate the NS-ARID genes in large families is homozygosity mapping. In this study, we surveyed allele frequency and allele heterozygosity of 17 NS-ARID STR markers linked to the six NS-ARID genes in Iranian population. Methods: The test group consisted of 120 unrelated healthy individuals. STR markers were designed using SERV software. Also, genotyping was done using multiplex PCR. Data was analyzed by Gene Mapper software. Allele frequency and observed heterozygosity rates were estimated using Power StatV12. Deviation from the Hardy Weinberg equilibrium (HWE) was performed based on the Exact test. Results: Out of 17 STR loci, 11 were novel. In total, 166 alleles were detected for the 17 markers. According to our study, the D9MAN1B1SD7.4, D19S872, D6GRIK2SI1.7, D19TECRSD1.8, D1ST3GAL3SI0.5, and D14ZC3H14SD5.3 STR loci were found to be the most informative and polymorphic STR markers for MAN1B1, ZNF526, GRIK2, TECR, ST3GAL3, and ZC3H14 genes, respectively. We also performed other statistical analyses on these STR markers and found that all of the 17 STRs were polymorphic and met the Hardy-Weinberg equilibrium. Conclusions: Finding novel STRs, with high allele heterozygosity, is one of the most significant outcomes of the present study. These findings can be useful for homozygosity mapping, PGD, and PND practices for the NSARID. Source


Falah M.,Tehran University of Medical Sciences | Houshmand M.,Iran National Institute of Genetic Engineering and Biotechnology | Akbaroghli S.,Tehran Welfare Organization | Mahmodian S.,Tehran University of Medical Sciences | And 2 more authors.
Iranian Journal of Basic Medical Sciences | Year: 2011

Objective(s) Despite the enormous heterogeneity of genetic hearing loss, most non-syndromic hearing losses are caused by mutations in the GJB2 gene. We aimed to characterize the mutation profiles of 100 Iranian deaf patients that were under 10 years old. Materials and Methods Patients were tested with direct sequencing of entire coding region of the GJB2 gene. Results Eight known mutations plus one novel (358delGAG) were found in 25% of study group. The 35delG mutation (64%) constituted the majority of GJB2 mutations. Conclusion Role of GJB2 mutation in Iranian young deaf population is more prominent than previous study that can be a result of higher consanguine marriage in population. But our result shows that there is only 25% nonsyndromic hearing loss due to high frequency of consanguine marriage in Iranian population. Identification of other genes involved in genetic deafness will help us understand the fundamental mechanisms of normal hearing, both in early diagnosis and therapy. Source


Rafati M.,Tehran University of Medical Sciences | Rafati M.,Comprehensive Genetic Center | Seyyedaboutorabi E.,Islamic Azad University at Tehran | Ghadirzadeh M.R.,Tehran Welfare Organization | And 11 more authors.
Molecular Cytogenetics | Year: 2012

Background: Interstitial Microdeletion and Microduplication syndromes have been proposed as a significant cause of sporadic intellectual disability (ID) but the role of such aberrations in familial ID has not yet been investigated. As the balanced chromosomal abnormalities commonly lead to the recurrent ID or multiple congenital anomalies, this study was designed to evaluate whether it was justified to investigate such aberrations in familial ID patients. Three hundred and twenty eight patients from 101 unrelated Iranian families with more than two ID patients in the first-degree relatives, have been investigated. Assessment of a panel of 21 common Microdeletion and Microduplication syndromes (CMMS) was carried out using Multiplex Ligation-Dependent Probe Amplification (MLPA) technique. Results: Among the families studied, 27.7% had 4-12, 35.6% had 3 and 36.6% had 2 affected individuals in the first-degree relatives. An autosomal dominant inheritance of Williams-Beuren syndrome (WBS) was detected in a family with no clinical suspicion of WBS. The prevalence of CMMS was therefore,0.99%. Conclusion: This is the first investigation of a panel of CMMS in a large sample set of "familial ID patients". The findings of this study showed the low prevalence of CMMSs in "familial ID" patients in spite of the significant contribution of such aberrations in "sporadic ID" which has a very useful practical impact by avoiding unnecessary diagnostic tests in "familial ID" patients. © 2012 Rafati et al; licensee BioMed Central Ltd. Source


Rafati M.,Tehran University of Medical Sciences | Rafati M.,Comprehensive Genetic Center | Ghadirzadeh M.R.,Tehran Welfare Organization | Heshmati Y.,Tehran Welfare Organization | And 8 more authors.
Molecular Cytogenetics | Year: 2012

Background: Cryptic subtelomeric rearrangements have been proposed as a significant cause of sporadic intellectual disability (ID) but the role of such aberrations in familial ID has not yet been studied. As positive family history of ID had been proposed as an important and significant predicting factor of subtelomeric rearrangements, it was assumed that the contribution of subtelomeric aberrations in familial ID would be much more than the sporadic ones. Three hundred and twenty two patients from 102 unrelated families with more than two ID patients in the first degree relatives have been investigated. Assessment of subtelomeric rearrangements were carried out using Multiplex Ligation-Dependent Probe Amplification (MLPA) technique. Detected aberrations were then confirmed by Fluorescence in Situ Hybridization (FISH) method. Results: Among the families studied, 27.4% had 4-12, 36.3% had 3 and 36.3% had 2 affected individuals in the first degree relatives. One unbalanced translocation and 4 polymorphic changes were detected. The prevalence of clinically significant subtelomeric rearrangements was 0.98%. Conclusion: This is the first investigation of subtelomeric aberrations in a large sample set of familial ID patients. Our results show that the contribution of subtelomeric rearrangements to familial ID is not as much as what had been determined for sporadic ones in the literature. Moreover, this study shows that the positive family history by alone, cannot be the most important and determining indicator of subtelomeric aberrations while it would be a good predicting factor when associated with dysmorphism or congenital malformations. These findings propose that other cryptic chromosomal abnormalities or even single gene disorders may be the main cause of familial ID rather than subtelomeric aberrations. © 2012 Rafati et al; licensee BioMed Central Ltd. Source

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