Genetic Hearing Loss FAQ

Why does my child have hearing loss?

Hearing science professionals estimate that 1 baby in 300 is born with some degree of hearing loss.

The cause of your child's hearing loss will be one of the following:

  1. Genetic – 50% of cases
  2. Non-genetic due to illness or trauma – 25% of cases
  3. Unknown – 25% of cases

In approximately 70% of cases of genetic hearing loss, the cause is autosomal recessive. About 12 babies per 10,000 have a recessive cause of their hearing loss. Congenital hearing loss (hearing loss present at birth) that is due to one of the many recessive genes is twice as common as Cystic Fibrosis, another recessive genetic condition.

Autosomal recessive inheritance means that:

  • Both parents are carriers of a gene that causes recessive hearing loss
  • There are many different genes in many different locations that may cause genetic hearing loss. A parent may carry one of the recessive genes responsible for deafness while the other copy of that same gene is normal. Because each parent has only one recessive gene that can cause hearing loss, both parents can hear normally.
  • If each parent passed on one copy of the mutated recessive gene, then the child would receive two mutated recessive genes (one from each parent). That is the cause of the recessive hearing loss.

In approximately 15% of cases of genetic hearing loss the cause is autosomal dominant. This means:

  • Only one copy of the mutated gene is sufficient to cause hearing loss. Therefore the parent (carrier) will have some degree of hearing loss. If the parent carrying the autosomal dominant gene also has other physical issues the hearing loss is called "syndromic". If only hearing loss is noted, it is referred to as "non-syndromic".
  • The parent with the dominant gene may pass that gene for hearing loss on to the child.

The remaining cases of genetic hearing loss include other forms of inheritance.

Why is my child being referred for Genetic Testing?

Genetic testing may determine whether your child's hearing loss is due to non-genetic causes or due to changes on a gene resulting in hearing loss. From this information, professionals can calculate the likelihood that other children in your family may also have a hearing loss due to the same cause. A full genetic evaluation will also determine if there are other health conditions that should also be addressed.

What does this mean for my child?

In general, why your child has a hearing loss does not affect how your child will be educated. Management of your child's hearing loss will be based upon the specific characteristics of your child and his or her communication needs. The findings from a genetic evaluation may be relevant for your child's medical care.

What is the likelihood that this will happen again with other children in my family?

If the cause of your child's hearing loss is an autosomal recessivegene, then the likelihood that this will happen in another child (assuming the same partner) is 1 in 4 (25%). If the cause of your child's hearing loss is an autosomal dominant gene, then the likelihood that this will happen in another child (assuming the same partner) is 1 in 2 (50%).

Should I have my other children tested?

If it is determined that you and your partner carry the silent (recessive) gene which causes a hearing loss, then each of the unaffected children resulting with that partner have a 1 in 3 (66%) chance of also carrying the mutated gene, but not having hearing loss.

Whether or not your unaffected children should be tested to determine if they also carry the deafness gene is a matter of choice. Your unaffected children may want to know their own gene carrier status so they would know whether to have their partners tested to determine if their children (your grandchildren) have a chance of having hearing loss due to this gene.

  • There is a 2 in 3 chance that unaffected siblings (brothers and sisters) of a child with recessive hearing loss carry the hearing loss gene (like you and your partner).
  • If this is the case, then their partner could be tested to determine if they are also a carrier. If that partner is also a carrier of the same gene, then each of their children would have a 1 in 4 (25%) chance of having the same genetic hearing loss.
  • If that partner does not carry the mutated gene, then all of their children would be unaffected, although each child would have a 50% chance of carrying the hearing loss gene.
  • There is a 1 in 3 chance that unaffected siblings do not carry the recessive hearing loss gene. If this is the case, there is virtually no chance of having a child with a hearing loss due to this gene.

Is this something that I need to be concerned about in my other relatives?

If you and your partner carry a recessive gene, then at least one of your parents and one of your partner's parents also carry the gene. This means that each of your brothers and sisters has a 50% chance of carrying the same gene.

How much does genetic testing cost?

The monetary costs of a genetic evaluation and medical tests are generally covered by your health insurance. Families should always check with their health insurance carrier to determine if genetic and medical tests are covered under their particular plan.