Introduction
To address the subject of deafness it is necessary to know what means to "hear".
When you hear a sound, the sound waves penetrate the outer part of the ear and spread along the
ear canal to the eardrum. These waves vibrate the eardrum then the bones in the middle part of the
ear. These vibrations are then transmitted to the inner ear or cochlea, an organ filled with fluid called
the endolymph. Tiny eyelashes covering the cochlea capture these vibrations and send signals to the
auditory nerve and then to the brain, where they are interpreted as sounds.
There are different degrees of deafness: mild, moderate, severe, deep. These different deafnesses
vary according to the degree of loss in decibels.
Deafness appears when an element of the ear is damaged (for example a perforation of the
eardrum, an absence of ciliated cells ...)
We now address the defect in the GJB2 gene which is linked to a certain type of deafness. Here are
some reminders regarding genetics so that you understand the deafness linked to this gene defect. In
the embryo, genes are used to form organs, and after birth to make them work. These genes, which
are passed on by mixing from generation to generation, are responsible for our various physical
characteristics. Each gene has a copy of itself, one from the father and one from the mother, which
are both identical and work in parallel. Scientists do not think they have discovered all of the genes
and estimate the number of different genes to be around 30,000. The genes are on chromosomes, in
the nucleus of a cell, the number of which is 46 (23 pairs) in the human being. Genes do not act
directly on our body but act on the proteins which act on our body. Genes are used to make the cell
work and to make proteins synthesized by the cell which have a particular action. The problem of this
deafness is thus linked to a pair of dysfunctional genes transmitted by the parents, which prevents
from producing the molecule necessary for hearing called, Connexin 26.
(when we hear a noise like that of a car or someone talking, our ear perceives a sound which will be decoded by the internal system of the ear to be transmitted to the brain via an auditory nervous message; the brain will interpret this sound then sort according to the situation then act, for example responding to someone talking to us or opening the door to the postman who has just rang.)
When you hear a sound, the sound waves penetrate the outer part of the ear and spread along the
ear canal to the eardrum. These waves vibrate the eardrum then the bones in the middle part of the
ear. These vibrations are then transmitted to the inner ear or cochlea, an organ filled with fluid called
the endolymph. Tiny eyelashes covering the cochlea capture these vibrations and send signals to the
auditory nerve and then to the brain, where they are interpreted as sounds.
There are different degrees of deafness: mild, moderate, severe, deep. These different deafnesses
vary according to the degree of loss in decibels.
 |
| source: https://www.audition.fr/systeme.html |
Deafness appears when an element of the ear is damaged (for example a perforation of the
eardrum, an absence of ciliated cells ...)
We now address the defect in the GJB2 gene which is linked to a certain type of deafness. Here are
some reminders regarding genetics so that you understand the deafness linked to this gene defect. In
the embryo, genes are used to form organs, and after birth to make them work. These genes, which
are passed on by mixing from generation to generation, are responsible for our various physical
characteristics. Each gene has a copy of itself, one from the father and one from the mother, which
are both identical and work in parallel. Scientists do not think they have discovered all of the genes
and estimate the number of different genes to be around 30,000. The genes are on chromosomes, in
the nucleus of a cell, the number of which is 46 (23 pairs) in the human being. Genes do not act
directly on our body but act on the proteins which act on our body. Genes are used to make the cell
work and to make proteins synthesized by the cell which have a particular action. The problem of this
deafness is thus linked to a pair of dysfunctional genes transmitted by the parents, which prevents
from producing the molecule necessary for hearing called, Connexin 26.
(when we hear a noise like that of a car or someone talking, our ear perceives a sound which will be decoded by the internal system of the ear to be transmitted to the brain via an auditory nervous message; the brain will interpret this sound then sort according to the situation then act, for example responding to someone talking to us or opening the door to the postman who has just rang.)
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