Gene Discovered in Childhood Language Disorder Provides Insight Into Reading Dis

[Guest guest]

What's exciting is that just think...one day going ahead we may not have to

worry about misdiagnosis if they can figure out how to test for each one

genetically!

Gene Discovered in Childhood Language Disorder

Provides Insight Into Reading Disorders

The recent discovery of a gene associated with specific language impairment

(SLI), a disorder that delays first words in children and slows their mastery of

language skills throughout their school years, offers new insight into how our

genes affect language development. The finding, published in the Journal of

Neurodevelopmental Disorders, is the result of a collaborative team effort

headed by Mabel Rice, Ph.D., a University of Kansas professor and NIDCD-funded

scientist.

The gene, KIAA0319, appears to play a key role in SLI, but it also plays a

supporting role in other learning disabilities such as dyslexia. The finding is

important for children with SLI and their families, and it is also likely to

improve the classification, diagnosis, and treatment of other language, reading,

and speech disorders.

SLI affects an estimated 7 percent of 5-6 year olds. Yet it is often overlooked

as a diagnosis because children with SLI typically don’t have severe

communication problems or an obvious cause for the impairment, such as hearing

loss. “These children are less likely to start talking within a normal

timeframe,†says Dr. Rice. “They may not begin to talk until they’re three

or four. And when they finally do talk, they use simpler sentence structure and

their grammar may seem immature.†Language impairments such as SLI also appear

to increase the risk for reading deficits.

Often childhood language difficulties are seen as only a mild problem, or

something kids eventually grow out of, but Dr. Rice says that’s not true.

“It persists. We know they don’t catch up and their limitations in language

continue as they move forward in school and then out into the workplace.â€

Because SLI tends to run in families, scientists suspected that genes played a

role. But tying the presence of a specific genetic mutation to SLI, or to any

inherited language impairment for that matter, had eluded researchers until

recently.

A total of 322 individuals took part in the study, selected from a large pool of

children, parents, and other family members participating in an ongoing

investigation of the long-term outcomes of children with SLI. Each individual in

the study was put through a battery of tests to assess speech, language, and

reading skills. Standard diagnostic tests†" the same tests that speech

pathologists use to diagnose language and learning disabilities†" were used to

establish measurable behavioral traits that can act as symptoms of SLI, much as

how fever is a symptom of the flu.

Using saliva samples to collect the DNA, the team identified a group of

candidate genes†" genes that previous studies indicated might have an

association with speech or reading disabilities†" and looked for mutations that

corresponded with SLI’s behavioral traits. Dr. Rice and her team scanned

millions of letters of genetic code looking for mutations that family members

have in common.

They discovered that mutations in one of the candidate genes for reading

disability, KIAA0319, had a strong effect on the language traits that are

characteristic of SLI, traits that can also be present in dyslexia, some cases

of autism, and speech sound disorders (conditions in which speech sounds are

either not produced, or produced or used incorrectly).

The next question, according to the researchers, is what does this gene do to

affect how we learn language? “It could be a gene that’s necessary in the

development of the cortex, the area of the brain where we do most of our

language processing,†says Dr. Rice. “Or maybe it’s a gene that’s

important for setting up neural pathways that are responsible for allowing

language to emerge on time. It could be a gene, or one of a family of genes,

that sets the stage to make language happen.â€

Dr. Rice contends that these findings lend support to the idea that difficulties

with reading and understanding printed text may be coming from the same genes

that influence difficulties in learning language. If this is so, she says, early

detection and diagnosis will be the key to helping children with SLI close the

reading gap between themselves and their peers. Interventions targeted to the

preschool years, she adds, when neural pathways in the brain’s language

regions are still plastic and open to change, can give preschoolers the chance

to develop their vocabulary and language skills in play settings and improve

their ability to communicate once they enter school.

Even better, this discovery takes the shame and blame out of SLI. In the past,

parents were often blamed for their child’s disability and told that they

hadn’t read to them enough. Children with SLI were called lazy or accused of

not working hard enough. Now, with the evidence that SLI is caused by a genetic

mutation, parents and children know that talking on time or speaking correctly

isn’t something that youngsters with SLI can will themselves into doing.

National Institute on Deafness and Other Communication Disorders

National Institutes of Health

31 Center Drive, MSC 2320

Bethesda, MD USA 20892-2320

E-mail: nidcdinfo@...

http://www.nidcd.nih.gov/news/releases/09/12_11_09

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