In Spain, more than 60% of hearing losses manifested at birth, childhood or in the first decades of adulthood, has a direct genetic cause. This is explained in the 'White Paper on Hearing Loss' of the Ministry of Health.
For that reason, Genetic evaluation, which analyzes DNA, is key to predicting and treating hearing loss. It is done simply from a small blood sample, according to Dr. Ignacio del Castillo of the Genetics Service of the Ramón y Cajal University Hospital in Madrid and CIBER of Rare Diseases (CIBERER).
Causes of hereditary hearing loss
In 30 percent of cases it is manifested by hereditary syndromic causes, which are associated with other medical problems, but 70 percent of the time, lack of hearing appears isolated. This is explained by Dr. Ignacio del Castillo of the Genetics Service of the Ramón y Cajal University Hospital in Madrid and CIBER of Rare Diseases (CIBERER). It states that:
“In non-syndromic hearing loss, we currently know more than 100 related genes. But, there are more than 300 syndromes that have associated hearing loss, also with different genes involved. And we know that a significant number of them still have to be identified. ”
In Babies and more Keys to know if your baby hears wellThe gene known as Connexin 26 is estimated to be behind 30% of cases of recessive hearing loss. Other frequent causes of severe genetic losses in our country are mutations in otorholine and mitochondrial DNA.
In this scenario, genetic tests are increasingly useful.
Advantages of genetic tests
The genetic test that analyzes the DNA it is done simply from a small blood sample, thanks to the great advances of the last three decades. As the researcher and doctor of Ramón y Cajal comments, "Great progress has been made in genetic diagnostic techniques to explore more genes in less time."
In addition, it adds a very encouraging data for children with hearing problems by explaining that progress is being made in a remarkable way towards specific therapies for each type of hearing loss, in what is called precision or personalized medicine.
"In the coming years, we will assist in the development of new individualized therapies, so it is very important to carry out the genetic test to know what type of hearing loss you have.That blood test:
It allows explaining the reason why a person has a hearing loss.
Receive genetic counseling and make a better prognosis.
Customize the treatment and obtain information on incidence in the offspring, because as explained by Dr. Castillo:
“In a family in which all its members have hearing loss, there may be different explanations. For example, all those affected could carry mutations in the same gene, but some could carry mutations in a different gene or even some could have a hearing loss of environmental cause. It is important to take into account the clinical characteristics of each person because this gives us clues about whether there is a single cause in the family or if there are several. ”
According to Dr. Rubén Polo, from the Otology Unit of the Otolaryngology Service of the Ramón y Cajal University Hospital, the genetic evaluation can be performed on babies. "In fact, in hearing loss, early diagnosis is essential", but also It is useful in people of all ages. It is available in Public Health, as in the Ramón y Cajal Hospital.
He also adds that "The genetic study is performed when there is a family history of hearing loss or when the cause of hearing loss is of unknown origin, since it can correspond to a genetic hearing loss even if there is no family history".
In cases where a genetic mutation is detected, family members will also be evaluated (including newborns) and children, to detect if they are carriers of the mutation, even if a hearing loss has not yet occurred.
Treatments for genetic hearing loss
For now, we will have to wait for these new therapies, since, as Dr. Polo explains, for now the treatment of choice for deep deafness of genetic origin with cochlear implants, "Although in the near future gene therapies based on animal models can give us new clues."
“The cochlear implant is the treatment of choice in patients suffering from profound deafness and in those with severe deafness who do not benefit from hearing aids. In recent years, we have seen an increase in their indications such as bilateral cochlear implantation, patients with residual hearing, for the treatment of disabling tinnitus, unilateral hearing loss, etc. ”.
In Babies and more Cochlear implants for babies with profound deafness, what are they and how do they work?According to experts, the identification and early treatment of hearing loss of genetic cause in children is decisive to avoid alterations in the acquisition of oral language. That is the opinion of Dr. Julio Rodrigo, general director of MED-EL Spain:
“Cochlear implants not only improve hearing performance, but also the self-esteem, social relationships and quality of life of adults with profound deafness. In pediatric patients they allow the development of oral language and integration into the educational system. In short, they contribute to normalize hearing impairment. ”
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