Mutations in TMC1 are a common cause of DFNB7/11 hearing loss in the Iranian population

Michael S. Hildebrand, Kimia Kahrizi, Catherine J. Bromhead, A. Eliot Shearer, Jennifer A. Webster, Hossein Khodaei, Rezvan Abtahi, Niloofar Bazazzadegan, Mojgan Babanejad, Nooshin Nikzat, William J. Kimberling, Dietrich Stephan, Patrick L.M. Huygen, Melanie Bahlo, Richard J.H. Smith, Hossein Najmabadi

Research output: Contribution to journalArticlepeer-review

27 Scopus citations


Objectives: We investigated the cause of autosomal recessive nonsyndromic hearing loss (ARNSHL) that segregated in 2 consanguineous Iranian families. Methods: Otologic and audiometric examinations were performed on affected members of each family. Genome-wide parametric multipoint linkage mapping using a recessive model was performed with Affymetrix 50K GeneChips or short tandem repeat polymorphisms. Direct sequencing was used to confirm the causative mutation in each family. Results: In 2 Iranian families, L-1651 and L-8600606, with ARNSHL that mapped to the DFNB7/11 locus, homozygosity for a reported splice site mutation (c.776+1G>A), and a novel deletion (c.1589-1590delCT; p.S530*) were identified in the TMC1 gene, respectively. Conclusions: Consistent with the previously reported phenotype in DFNB7/11 families, the 2 Iranian families had segregated congenital, profound hearing impairment. However, in family L-1651, one affected family member (IV:3) has milder hearing impairment than expected, suggesting a potential genetic modifier effect. These results indicate that DFNB7/11 is a common form of genetic hearing loss in Iran, because this population is the source of 6 of the 29 TMC1 mutations reported worldwide.

Original languageEnglish (US)
Pages (from-to)830-835
Number of pages6
JournalAnnals of Otology, Rhinology and Laryngology
Issue number12
StatePublished - Dec 2010
Externally publishedYes


  • DFNB7/11
  • Deletion
  • Splice site mutation
  • TMC1 gene

ASJC Scopus subject areas

  • Otorhinolaryngology


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