Specific language impairment and autism share genetic links, according to a study published October 30. Researchers, for the first time, studied the molecular genetics of families with a history of both autism spectrum disorders (ASD) and language disorders, report scientists from Nationwide Children’s Hospital in Ohio.
Although autism affects about 1 in 88 children in the United States, not all children with autism have language problems. Estimates on the number of children with autism and a language disorder range from about 50 percent to as high as 66 percent. The results of this research are particularly important as they partially explain why some children with ASD have language problems when other children with ASD do not.
Seventy-nine families who had a child with autism and another child with a language disorder were studied. Blood tests and clinical tests evaluating grammar, vocabulary and language processing were studied by the research team, which included experts from Rutgers University. The team looked for common genetic factors to determine if ASD and specific language impairment were connected.
“A genetic cause of language impairment may help explain why some kids with ASD have language impairments and others don’t, as well as why some members of a family have language impairment only and others have ASD as well,” says Christopher W. Bartlett, Ph.D., lead author of the study. Bartlett also commented,“This research is important because it is hard to understand autism until we find the genes that might be involved. But most of all, we want to know why there is such a range in communication abilities in children with autism—why so many children have language difficulties when it’s not required for the diagnosis.”
Further research on the genetics of these families is planned. The goal of that research is to try and pinpoint the exact genes and gene mutations that are common in ASD and specific language impairment.
Specific language impairment explained
The National Institutes of Health report that between seven and eight percent of all children suffer from specific language impairment (SLI). It is a common learning disability that is also called developmental language disorder, language delay or developmental dysphasia.
The symptoms of SLI include:
- delay in starting to talk
- talking but not in an understandable way
- struggling with new words
A speech and language therapist usually diagnoses SLI. Treatment for this disorder includes language enrichment programs and speech and language therapy.
More information on SLI is available from the National Institutes for Health.
The Mayo Clinic defines autism as a "serious developmental delay." The symptoms of autism can vary from child to child, but typically include difficulties with social interactions, behaviors and language. Specific symptoms of autism include:
- poor eye contact
- being unaware of other's feelings
- not responding to his or her name
- lack of speech or delayed speech
- difficulty maintaining a conversation
- difficulty with imaginative or social play
- repetitive behaviors
- inflexible adherence to specific routines or rituals
An autism specialist generally diagnoses autism through observations and evaluations. A variety of therapies are used to treat children with autism. These therapies include occupational therapy, speech and language therapy, psychological therapy and Applied Behavioral Analysis.
More information on autism is available from the Mayo Clinic.
The study, "A Genome Scan for Loci Shared by Autism Spectrum Disorder and Language Impairment," is published in the American Journal of Psychiatry.