Connexin 26 mutations, hearing loss and infection rates

Dr Amanda Hall at the University of Bristol is currently conducting a study with colleagues at the Institute of Child Health in London and at the University of Southampton, to look at the effect of a common genetic mutation in the Connexin 26 gene on hearing.

(Small project grant: 2010-2011)

Connexin 26 is a gene involved in maintaining the balance of fluids in the inner ear. Having two copies of the mutation leads to permanent deafness, however the impact of being a carrier of the mutation (having only one copy) on hearing is still under debate. Additionally there may be an advantageous effect of carrying the connexin 26 mutation: recent studies have shown that carrying the mutation is associated with increased skin thickness, which could protect against skin or gut bacterial infections.

This study, funded by Deafness Research UK, aims to investigate whether those carrying one copy of the connexin 26 mutation show any differences in hearing or infection rate compared to those not carrying the mutation.

The research will be carried out as part of the Avon Longitudinal Study of Parents and Children, a large study that has followed the health and development of a large group of children born in 1991 – 1992. The study holds detailed genetic, hearing and infection information on approximately 7,000 children in the group and it has been shown that 1-2% carry one copy of the connexin 26 mutation.

Over 18 months, the research will involve analysis of hearing and otoacoustic emission waveforms (a measure of inner ear function) measured at age 7 – 11 years, as well as parental reports of child infection rates up to age 4 years. By comparing this data collected from the children, the team hope to find out whether there are any differences between those with and those without the connexin 26 mutation. The team also hope to find out whether there is any advantage in having one copy of the mutation, as this may explain why it is so common.