By Megan Ahlman, M.A. CCC-SLP,
Cleveland Hearing & Speech Center
Evidence exists linking genetic factors to a variety of speech and language difficulties. Recent studies of molecular genetics and neuroimaging are cross-disciplinary, combining forces between speech-language pathologists, physicians and scientists. Researchers have already identified over 400 genes linked to hearing loss, and ongoing studies investigate genetic links to stuttering, voice disorders and language disorders.
There are several types of speech and language disorders that appear to be closely tied with genetics.
- Specific Language Impairment (SLI)
- As many as 50-70% of children who have SLI also have at least one family member who struggles with the disorder.
- The incidence in families with a history of SLI is estimated at approximately 20-40%, whereas in the general population the estimated incidence is about 4%.
- Identical twins show a higher concordance rate for language-based learning disorders compared to fraternal twins.
- There are higher rates of SLI in males compared to females.
- There are signs that genetics plays a part in at least some of these instances.
- Speech-sound disorders
- There are higher concordance rates for identical male twins (70%) on articulation and language disorders compared to fraternal twins (46%).
- Childhood apraxia of speech (CAS)
- Mutations on the FOXP2 gene have been linked to family members with CAS.
Only a small fraction of all cases of speech and language disorders can be explained by genetic findings. There are many potential causes of speech and language disorders, some of which are still unknown.
Tips for Parents:
1. Don’t play the blame game.
Advancements in medical and scientific research reveal that you can inherit susceptibility to speech and language disorders, just like you might inherit increased risks for diabetes or other medical conditions.
2. Ask your child’s pediatrician about precautions if you received speech-language services as a child.
Understanding family medical history can help you make better decisions about preventative care and speech therapy. When completing health forms, keep in mind that even though “speech disorder” might not be listed, there may be genetic tendencies in your family. Talk with the doctor about other related health issues that may be genetic. Some early genetic findings related to communication include ties to disorders such as Autism or Fragile X Syndrome.
3. Find a qualified SLP.
All speech-language pathologists are trained in general knowledge regarding genetics, syndromes and disorders. Ask the speech language pathologist if they are familiar with the most recent research if you have questions about a particular diagnosis. It can be challenging for clinical SLPs to find, access and keep abreast of this literature, but they can work with you to ensure therapy is effective and evidence-based.
4. Begin speech and language services as early as possible.
Don’t write off difficulties if speech and language disorders don’t run in your family. The importance of early intervention, or getting help for young children, cannot be emphasized enough when there may be a family history of speech and language difficulties.