1
|
Tabatabaiefar MA, Alasti F, Zohour MM, Shariati L, Farrokhi E, Farhud DD, Camp GV, Noori-Daloii MR, Chaleshtori MH. Genetic Linkage Analysis of 15 DFNB Loci in a Group of Iranian Families with Autosomal Recessive Hearing Loss. Iran J Public Health 2011; 40:34-48. [PMID: 23113071 PMCID: PMC3481767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Accepted: 02/13/2011] [Indexed: 11/22/2022]
Abstract
BACKGROUND 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. METHODS 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. RESULTS 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. CONCLUSION 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.
Collapse
Affiliation(s)
- MA Tabatabaiefar
- Cellular and Molecular Research Center, School of Medicine, Shahrekord University of Medical Sciences, Shahrekord, Iran,Dept. of Medical Genetics, School of Medicine, Jundishapur University of Medical Sciences, Ahvaz, Iran,Dept. of Medical Genetics, University of Antwerp, 2610, Antwerp, Belgium
| | - F Alasti
- Dept. of Medical Genetics, University of Antwerp, 2610, Antwerp, Belgium,National Institute for Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran
| | - M Montazer Zohour
- Cellular and Molecular Research Center, School of Medicine, Shahrekord University of Medical Sciences, Shahrekord, Iran,Dept. of Medical Genetics, School of Medicine, Tarbiat Modares University, Tehran, Iran
| | - L Shariati
- Cellular and Molecular Research Center, School of Medicine, Shahrekord University of Medical Sciences, Shahrekord, Iran,Dept. of Molecular Medicine, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - E Farrokhi
- Cellular and Molecular Research Center, School of Medicine, Shahrekord University of Medical Sciences, Shahrekord, Iran
| | - DD Farhud
- School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - GV Camp
- Dept. of Medical Genetics, University of Antwerp, 2610, Antwerp, Belgium
| | - MR Noori-Daloii
- Dept. of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - M Hashemzadeh Chaleshtori
- Cellular and Molecular Research Center, School of Medicine, Shahrekord University of Medical Sciences, Shahrekord, Iran,Corresponding author: Tel: +98 381 3335654, Fax: +98 381 3330709, E-mail:
| |
Collapse
|
2
|
Chen W, Meyer NC, McKenna MJ, Pfister M, McBride DJ, Fukushima K, Thys M, Camp GV, Smith RJH. Single-nucleotide polymorphisms in the COL1A1 regulatory regions are associated with otosclerosis. Clin Genet 2007; 71:406-14. [PMID: 17489845 DOI: 10.1111/j.1399-0004.2007.00794.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Otosclerosis (MIM 166800) has a prevalence of 0.2-1% among white adults, making it the single most common cause of hearing impairment in this ethnic group. Although measles virus, hormones, human leukocyte antigen alleles and genetic factors have been implicated in the development of otosclerosis, its etiology remains unknown. In a focused effort to identify genetic factors in otosclerosis, we have mapped four disease loci (MIM 166800/605727/608244/608787); however, cloning the disease-causing genes in these intervals has not been successful. Here, we used a case-control study design to investigate the association between collagen type I genes and otosclerosis. We identified susceptibility and protective haplotypes in COL1A1 that are significantly associated with otosclerosis in the Caucasian population. These haplotypes alter reporter gene activity in an osteoblast cell line by affecting binding of transcription factors to cis-acting elements. Our data suggest that increased amounts of collagen alpha1(I) homotrimers are causally related to the development of otosclerosis. Consistent with this hypothesis, mouse mutants homozygous for a Col1a2 frameshift mutation on a C57BL/6J background that deposit only homotrimeric type I collagen have hearing loss.
Collapse
Affiliation(s)
- W Chen
- Molecular Otolaryngology Research Laboratories, Department of Otolaryngology, The University of Iowa, Iowa City, Iowa 52242, USA
| | | | | | | | | | | | | | | | | |
Collapse
|