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Hearing loss - Genetics evaluation

Why was my child referred to genetics?

The main goal of a genetics visit is to understand the cause of your child’s hearing loss.

Some types of hearing loss can be related to other health conditions. A genetics visit can help find out if your child is at risk for other health problems. You can also find out if there is a chance for other people in your family to have hearing loss, including future children. Most children with hearing loss are referred to the genetics clinic even if there is no family history of hearing loss.

What happens after the visit?

If genetic testing is recommended and completed, you will receive a phone call from the genetic counselor to review the results and recommendations. Most children have at least one follow up visit in Genetics clinic. If a cause of hearing loss is identified, you will be invited back for education. If all initial testing is negative/normal, you may be invited back to consider other causes of hearing loss.

Can a cause for hearing loss always be found?

Not always. About half of all childhood hearing loss is genetic, but the exact cause is not always identified. Another 20-25% of cases are due to environmental factors, while 25-30% of cases have an unknown cause.

What are different types of hearing loss?

There are three main types of hearing loss; these are sensorineural hearing loss, conductive hearing loss and mixed hearing loss.

Sensorineural Hearing Loss (SN) comes from a malfunction of inner ear structures (cochlea).

Conductive Hearing Loss comes from abnormalities of the external ear and/or the ossicles of the middles ear. Ossicles are the three small bones in the ear that transmit sounds into the inner ear.

Mixed Hearing Loss is a combination of conductive and sensorineural hearing loss. It includes malfunctions/abnormalities of both the inner and outer ear structures.

What are the main causes of hearing loss?

There are three main causes of hearing loss: syndromic hearing loss, non-syndromic hearing loss, and environmentally caused hearing loss.

Syndromic hearing loss is hearing loss associated with malformations of the external ear or with medical problems involving other organ systems.

Non-syndromic hearing loss is hearing loss not associated with any visible abnormalities of the external ear or any other related medical problems.

Environmentally caused hearing loss is caused by exposures to a child, both before and after birth. Environmental causes can be prematurity, alcohol exposure during pregnancy, infections during pregnancy or after birth, or medicines that damage the auditory nerve.

More specific environmental causes can include preeclampsia, prematurity, Rh incompatibility complications, prenatal inflections such as toxoplasmosis, rubella, cytomegalo virus, and herpes, and infections after birth like bacterial meningitis. Medicines that can damage the auditory nerve include antibiotics like gentamicin, and certain types of chemotherapy drugs that can damage the inner ear.

Resources

Children’s Hospital Specialty Center
Genetics and Genomics Program
2530 Chicago Avenue South
Minneapolis, MN 55404
612-813-7240

Questions?

This information is for general use only. For specific medical advice or questions, consult your health care provider.

Last reviewed 10/2019

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This page is not specific to your child, but provides general information on the topic above. If you have any questions, please call your clinic. For more reading material about this and other health topics, please call or visit Children's Minnesota Family Resource Center library, or visit www.childrensmn.org/educationmaterials.

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