Can you inherit hearing loss from your parents? The short answer is yes, but it’s not quite that simple. In today’s article, we’ll explore the science behind hereditary hearing loss, its causes, key symptoms, preventive measures, and treatment options available.
Genetic hearing loss can be non-syndromic or syndromic. Non-syndromic hearing loss (inherited by gene variants) refers to a partial or total loss of hearing that is not associated with other signs, symptoms, or medical conditions.
Syndromic hearing loss occurs alongside other health conditions. The American Academy of Audiology reports that up to 30 percent of hereditary hearing impairments are syndromic, and there are over 400 known syndromes that include hearing loss and affect various other systems of the body, including the eyes, heart, and kidneys.
Hearing health can also be affected by other medical conditions that may run in families, such as diabetes and heart disease.
Most babies with hearing loss are born to parents without hearing loss; however, a genetic mutation or change can occur that leads to hearing loss.
According to the University of Michigan, research has found that when a child is born with non-syndromic sensorineural hearing loss or develops it in early childhood, 50 percent of the time it’s caused by a genetic mutation or a change in the GJB2 gene, which we’ll discuss below. The majority of these children with genetic hearing loss did not have any birth defects or other health conditions that were connected to their hearing loss.
Gap Junction Beta 2 (GJB2) and Connexin 26
What do the GJB2 gene and Connexin 26 have to do with non-syndromic hearing loss? Mutations in the GJB2 gene are a leading cause of non-syndromic hearing impairments in many populations, resulting in congenital deafness and late-onset hearing loss.
Everyone has two GJB2 genes, one from each parent. Most genetic changes that cause hearing loss are recessive, meaning that there is one identical copy of full hearing and one changed gene. If a child has two mutated GBJ2 genes from each parent, the child can be born with hearing loss, even if both parents have normal hearing.
Connexin 26 is a gap-junction channel protein encoded by the GJB2 gene that is present in cells throughout the body, including the inner ear. Its function is to help move with intercellular communication between supporting cells and maintain an equilibrium of cochlear fluids. This protein helps to move nutrients and ions which signals the molecules between cells.
Some forms of genetic hearing loss can be associated with a genetic syndrome, where there are other health conditions present, such as developmental defects, vision loss, and abnormalities.
The American Academy of Audiology highlights that syndromic hearing loss can be inherited via one of the following patterns:
An X-linked inheritance pattern happens when the mutated gene on the X chromosome is passed on from the mother to her son, and the son expresses the syndrome.
A few of the many syndromes that are associated with hearing loss include:
Genetic hearing loss can be associated with other congenital abnormalities, such as:
Ear canal abnormalities
Microtia is a congenital abnormality involving a malformation of the outer ear. This can range from a structural issue like a narrow ear canal to the external ear being completely missing. Microtia occurs during pregnancy and can affect one or both ears. When this abnormality affects the ear canal, it can cause hearing loss and difficulties which direction a sound comes from.
Craniofacial malformations
Micrognathia is characterized by a smaller jaw or chin. This condition is often syndromic and can cause conductive hearing loss.
Facial asymmetry and conditions such as microcephaly (when a baby is born with a smaller than average head) or craniosynostosis (a condition where the baby’s skull bones fuse together too early) can also impact a child’s hearing.
Babies born with cleft lips or palates may also have hearing loss.
Ocular abnormalities
Abnormalities and syndromic conditions related to vision can also have a connection with hearing loss, such as Waardenburg syndrome, which is a rare genetic condition where individuals may have eyes with different iris colors, generalized pigmentation abnormalities, and varying degrees of hearing loss.
Other syndromic abnormalities can include cysts, preauricular pits (misplaced sinus tract), telecanthus (increased distance between the inner corners of your eyelids), pigmentary retinopathy, or high myopia (nearsightedness) can also have connections to hearing loss.
General signs of hearing loss may appear different between children and adults. A few of these signs are included below.
If hearing loss runs in your family, you may consider genetic testing. This information can be used to determine if other family members, such as your children and grandchildren, carry genetic mutations associated with certain types of conditions. Understanding the genetic cause of hearing loss can be helpful in treating hearing loss, especially since some forms of genetic hearing loss have onset later in life or may have a progressive component.
There are a few types of genetic testing that can look for genetic changes, or mutations, in a person’s DNA. Genetic testing is done via blood draw and samples are sent to a diagnostic laboratory for testing.
At this time, there is no Food and Drug Administration-approved gene therapy or curative treatment available for hereditary hearing loss; however, your audiologist may recommend hearing aids, or in cases of hearing conductive loss, bone-anchored hearing aids may be appropriate.
Request an appointment at a hearing care provider near you.
