Reporting the presence of three different diseases causing GJB2 mutations in a consanguineous deaf family

Abstract

Objective: This paper reports a consanguineous deaf family with three different mutations in the GJB2 gene. Design: Four members of an Iranian deaf family were recruited in this study. The GJB2 coding region and exon-intron boundaries were investigated using direct sequencing. Study sample: The proposita was a 12-year-old girl with congenital non-syndromic hearing loss. She was born to consanguineous parents. The proposita, her parents and deaf maternal uncle were screened for GJB2 mutations. Results: Sequencing demonstrated the presence of the c.176_191del and c.327_328delGGinsA mutations in the proposita, the c.176_191del mutation in her father, and the c.35delG and c.327_328delGGinsA mutations in trans in her apparently unaffected mother as well as in her congenitally deaf uncle. Follow-up pure-tone audiometry revealed moderate to severe mid- and high-frequency hearing loss in the mother. Conclusions: This study shows the complexity of genetic testing and counseling for hearing loss.

Key Words::

• Deafness
• GJB2
• mutation
• autosomal recessive non-syndromic hearing loss
• consanguinity
• intrafamilial
• heterogeneity

Acknowledgements

The authors would like to gratefully thank the Irn-Deaf-11354 family who took the time to contribute to this study. Note: Elham Davoudi-Dehaghani and Mohammad-Sadegh Fallah have contributed equally to this paper.

Declaration of interest: This study is a part of a PhD thesis and has been financially supported by the Kawsar Human Genetics Research Center and Pasteur Institute of Iran.