Results of Genetic Testing

The Audiologist referred Kairi to have genetic testing done to try to help determine the cause of he hearing loss. The genetic testing will be looking for the presence of connexin 26 and connexin 30 genes.

The meeting consisted of an interview with the parents to obtain family medical history. Neither one of us has had any hearing loss in our family. We have another son and he can hear perfectly fine.

The second part of the testing is a blood sample that will test for the connexin genes. A few weeks after the testing, we received word that Kairi did have mutations in the connexin 26 genes.

So for those who are not biology majors, let me break it down for you.

Every person is made up of genes. These genes come in pairs. So for hair color you may have a pair of brown genes, BB for example. If you have one brown and one blond then you may have BD. If you have one of each, what color hair will you have? That depends on the dominant gene. Whichever is the dominant gene in this case will win. So lets say that blond is dominant. So BD will create a person that is blond.

So for connexin 26, Kairi has CC. That means that both of us, her parents, have 1 connexin gene each. Because if either of us had both, then we would also have hearing loss.

Our chances of having a child with hearing loss are as follows. CC, CN, NN. So we have a 1 in 3 chance of having a child with hearing loss.

The good news about Kairi having connexin 26 is that it makes Kairi a candidate for a cochlear implant. This is just an initial assessment since many other factors will come into play along the line. But, usually patients who have connexin related hearing loss don't have any physical abnormalities related to the ear. This is what makes them a good candidate.