of Hearing Loss
to some frequently asked questions
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did this happen to my child?
Hearing science professionals estimate that 1 in 300 babies
are born with some degree of hearing loss. Human genetic
professionals estimate that half of those cases of hearing
loss are due to the genes that the baby inherited. 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 about
twice as common as Cystic Fibrosis, another recessive genetic
To answer the question, "Why did
this happen to my child?" there could be at least one
of three answers.
- Unknown (the cause of the hearing
loss cannot be discovered)
- Non-genetic (illness or trauma before,
during or after birth)
- Genetic (the hearing loss will depend
on the type of inheritance present)
In 70% of cases of genetic hearing
loss, the cause is autosomal recessive; therefore,
- 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. At one of these locations, a parent my carry one
of the recessive genes that can cause deafness and one
of the dominant genes that is responsible for normal hearing.
Because each parent has only one recessive gene that can
cause hearing loss, both parents can hear.
- If each parent passed on one recessive
gene, then the child would receive two recessive genes
(one from each parent) and that is the cause of the recessive
15% of cases of genetic hearing loss the cause is autosomal
- In this case only one parent may
have the dominant gene for hearing loss. That parent will
have some degree of hearing loss. If the autosomal dominant
gene also has other physical findings (i.e., it is syndromic),
the parent who has the dominant gene also may have some
of these other physical findings.
- The parent with the dominant gene
may pass that gene for hearing loss on to the child.
For the final and remaining 15% of
genetic hearing loss cases, the answer to the question,
"Why did this happen to my child?" is specific
to the particular type of genetic inheritance.
Why is my child being referred for
Genetic testing may determine whether your child's hearing
loss is due to non-genetic causes or to a gene that causes
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 also need to be addressed.
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
What is the likelihood that this
will happen again with any other children in my family?
If the cause of your child's hearing loss is an autosomal
recessive gene, 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
If it is determined that you and your partner carry the
silent (recessive) gene which causes a hearing loss, then
each of the children resulting with that partner have a
2 in 3 (66%) chance of also carrying that same gene.
Whether or not your hearing children
should be tested to determine if they also carry the deafness
gene is a matter of choice. Your hearing 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.
is a 2 in 3 chance that hearing 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 life 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 same gene, then
all of their children would be hearing, although each child
would have a 50% chance of carrying the hearing loss gene.
There is a 1 in 3 chance that hearing
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, as the gene
is not passed on.
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 1 in 2 (50%) chance of carrying the same
will all this 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.
Some people experience the psychological
cost of guilt that they were responsible for this condition
in their child. Be assured that everyone carries some recessive
genes that, if present in a double dose, would cause some
sort of genetic condition. Guilt feelings are natural during
the stages of grieving and acceptance of your child's hearing
loss. However, if those feelings persist or if they affect
your ability to function day-to-day, please seek out someone
who can help.