(Thanks to Steve Anderson for forwarding this find)
Inarticulate family leads researchers to speech gene
January 26, 1998
Web posted at: 5:31 p.m. EST (2231 GMT)
WASHINGTON (Reuters) -- A family plagued by an inability to make themselves understood has led to the first proof of a gene controlling human speech, researchers said Monday.
Geneticist Anthony Monaco and colleagues at Oxford University in Britain have named the gene SPEECH1.
"It's definite confirmation and first evidence of a real gene involved in language development," Monaco said in a telephone interview.
"It means that genes are probably heavily involved in the ability to acquire language."
Experts have long said humans are "hard-wired" to acquire language, and the area of the brain involved, known as the planum temporale, has been identified.
Children who get no language input -- for instance, profoundly deaf children who are never taught sign language -- still make up their own languages, with grammar and sentence structure.
'Two different language problems'
Monaco, who also helped map the gene for muscular dystrophy, set out to see how genes might be involved in language. His team studied a family with a history of language disorders.
"They have two different language problems -- one is in articulation of speech. They are very hard to understand."
The condition is known as motor dyspraxia. "It's a fancy word for not being able to get the words out and be intelligible," said Monaco, who reported the findings in the journal Nature Genetics on Monday.
"The separate problem is that their speech is very rudimentary -- it isn't developed according to the age the child should be. They don't achieve the milestones at the age they should, for instance getting tenses and grammar wrong."
It's a dominant gene
The gene, tracked to chromosome seven, is a dominant gene, meaning that people only have to inherit one copy to be affected. Males and females are equally affected by it.
Probably by coincidence, it is near the gene known to cause cystic fibrosis when mutated.
Now Monaco's team is looking to see if there is a mutation of the gene, or perhaps a deletion in which large pieces of genetic matter are simply missing.
The effects are particularly strong in this one British family, but Monaco said speech disorders like theirs, on a smaller scale, affect up to 2 percent of schoolchildren.
"What we hope is if we can understand the gene it can tell us more about the process on which language is built," he said.
Suspected link to autism, dyslexia
Monaco is doing a larger study with 100 families whose members have speech disorders. He suspects there could be a link with autism, which causes victims to withdraw, and dyslexia, which causes people to have trouble reading.
"Lots of children with language problems go on to have reading problems," he said. "We just did a screen for autism and to our surprise we found the same region of chromosome seven."
This might not mean anything, but the researchers were checking further, Monaco said.
Copyright 1998 Reuters Limited. All rights reserved.
Related sites:
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- The Wellcome Trust Centre for Human Genetics
- UK Medical Research Council Human Genome Mapping Project Resource Centre (HGMP-RC)
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