IBBIOTECH

Experiencia y futuro en biotecnología

Genetic study of deafness

Genetics is a very useful tool for the medical study of deafness.

Hearing loss (hearing level decreased below normal, 20dB) can be classified according to several features, including the time of acquisition (prelinguistic or post-lingual), the degree of intensity (mild, moderate, severe, profound or cofosis ) and location (conductive, sensorineural or mixed).

Sensorineural deafness due to lesions in the inner ear or auditory nerve pathway is the most common form of congenital hearing loss. The incidence is estimated at 1:1000 newborns.

Among the known causes of sensorineural hearing loss are the genes that are responsible for more than 50% of severe to profound congenital hearing loss. They can be syndromic (if associated with other pathologies) or nonsyndromic (isolated condition). Classified according to the mode of inheritance: autosomal recessive (82%), autosomal dominant (15%), sex-linked recessive (2%) or mitochondrial (1%). In recent years advances in molecular biology have identified the genes related to nonsyndromic sensory hearing loss.

WHAT ARE THE BENEFITS OF A GENETIC STUDY OF HEARING LOSS?

Knowledge of the genetic cause that produces hearing loss can lead to important decisions in the treatment and monitoring of the disease, not least for establishing the origin and the type of injury occurred in the auditory system. With regards to treatment, such as HNS of 35G caused by the mutation in the gene GJB2, such sufferers are ideal candidates for cochlear implants. Furthermore, in some cases, the information derived from genetic studies can help predict whether the hearing loss remains stable or will worsen over time.

It is also important to have information from genetic studies at the moment of thinking about having a family. If the genetic cause is known, then we can predict the likelihood that the offspring will also suffer hearing loss. Likewise, genetic studies will allow an earlier diagnosis of hearing loss in children, informing parents of the causes of the disease.

HOW TO CARRY OUT THE GENETIC STUDY?

There are several options for this genetic study. On the one hand, your Ear-Nose-Throat specialist, family GP or paediatrician may indicate the study depending on your medical history (history of your case) and a review of your family history.

On the other hand, you are welcome to come to our IB BIOTECH centre or contact us directly through our website or by e-mail for an appointment. You will be asked to bring our team of geneticists some information which will be useful in guiding the genetic study of hearing loss. You will need to elaborate family history of hearing loss, clinical data, time of onset and exclude possible environmental etiology. As a result of all this information our team will inform you of the most appropriate genetic study for you.

If you decide to carry out the study and have signed the consent forms, we will take a blood sample. You can also take a muccous sample at home while using our Home Sampling kit. The procedure is simple. In the kit you will find sterile cotton swabs, with which you rub the inside of the mouth. Handle the samples carefully. Do not touch the cotton swab with your fingers. Once you have taken the sample and it has been properly packaged, as per the instructions, you can send it back to us along with the all the relevant forms duly signed that are included in the kit.