The ‘deaf gene’
By Gordon Hay, Community Manager
My brother and his partner have the deaf gene, therefore should they decide to try for a baby, the baby will be deaf. The reason is as follows:
Connexin 26 is the name of a protein that is related to hereditary hearing loss. There is a gene called GJB2 which has the instructions to tell the body how to make Connexin 26. If the gene is mutated then not enough Connexin 26 protein is made which affects the way hair cells in the cochlea talk to each other which leads to a sensorineural hearing loss. Connexin 26 mutations are responsible for at least 20% of all genetic hearing loss.
Every cell in your body has 23 pairs of chromosomes. One chromosome from each pair is inherited from your mother and one from your father. Connexin 26 mutations are genetically transmitted from parent to child in a recessive manner. This means if a child inherits 2 mutated genes, one from each parent, they will experience a hearing loss. If a child inherits 1 mutated gene and 1 normal gene then they will not have a hearing loss but are known as a carrier. If a carrier has a child with someone who also has the Connexin 26 mutation there is a 1 in 4 chance their child will have a hearing loss.
It is known as a pre-lingual hearing loss because it affects the child before they have developed speech. This hearing loss is generally stable so it will not get worse over time. At the moment there is no therapy that can change the genes so the options are to use hearing aids or have a cochlear implant.
It is possible to have a consultation in a genetic clinic to find out genetic information about your, or your child’s deafness. Some people aren’t interested in finding out more as there is nothing medical that can be done to change the mutated gene, however, some people like to know as it allows them to consider what may happen if they have children.
If you would like genetic information about your own deafness you will need to arrange a consultation. There are National Health Service centres offering free, genetic counselling for deafness around the country. Speak to your GP, paediatrician, audiological physician or ear, nose and throat consultant to find out more and ask for a referral.