Mice bred with 'squeak defect'
Published 21/02/2011 | 07:06
Stuttering mice with a "squeak defect" version of the affliction suffered by King George VI are being bred by scientists.
They hope the creatures, given human gene mutations, will help them better understand the disorder graphically depicted by award-winning actor Colin Firth in the film The King's Speech.
Researchers have already started making ultrasonic recordings of sounds made by the genetically-engineered mice. But they are still trying to solve the problem of recognising when an animal is experiencing the mouse equivalent of stuttering.
If a stuttering mouse can be developed it will provide a valuable research tool which could pave the way to drug treatments.
Around 1% of the population suffers from stuttering, but around five time more pre-school children are affected. Many recover powers of normal speech as they get older.
Stuttering is defined as "involuntary hesitation, sound prolongation or repetition of syllables in speech". Sufferers may find themselves held back at school or turned down for jobs. Often they struggle continuously to avoid words and phrases that cause them embarrassment.
Scientists have now identified mutations in three genes involved in cell metabolism that seemed to be linked to stuttering. The same gene defects appear to underlie two rare but fatal childhood metabolic disorders called mucolipidosis type 1 and 2.
Children with the more serious type 1 condition usually die before the age of 10, but intriguingly they never develop the power of speech. Learning more about how the gene mutations contribute to stuttering could yield molecular targets for drug development.
Mice bearing the mutations are being developed by Dr Dennis Drayna, from the National Institute on Deafness and Other Communication Disorders in Bethesda, Maryland, US.
Speaking at the American Association for the Advancement of Science's annual meeting in Washington DC, he said: "We've taken human stuttering mutations and put them in mouse genes." But he added that mouse vocal communication was "very poorly understood".