Squeak defects in mice could help treat human stutterers

 

The mystery of why some children begin to stutter in the first few years of life, and never fully recover from the speech impediment, may soon be solved with the creation of the world’s first “stuttering” mouse.

Scientists have generated laboratory mice with the same genetic mutations believed to be involved in triggering the speech disorder in humans in the hope that the genetically engineered animals will provide new insights into understanding and treating the condition in people.

The mice are currently undergoing tests to determine whether their high-pitched calls, which cannot be heard by the human ear, display any characteristic signs that could be linked with the mutations inserted into their DNA.

The researchers believe that the prospect of creating stuttering laboratory mice could revolutionise research into the human condition because it would allow scientists to make detailed studies of the chemical changes within the brain cells of individuals with a stutter.

Although not all stuttering is caused by genes alone, scientists have shown that a sizeable proportion of people who suffer from a stutter are likely to have inherited genetic mutations that predispose them to developing the condition, which usually begins between the ages of three or four.

“We know that about half the people who present themselves for stuttering therapy have a clear family history of the disorder. So a rough guess is that maybe half of stuttering is due to things that are inherited in a family, but we don’t know exactly,” said Dennis Drayna of the US National Institute on Deafness and Other Communication Disorders in Bethesda, Maryland.

“We’ve begun to find genes that contain mutations that do cause stuttering. It’s clear that they don’t cause all of the disorder, in fact a large fraction of the disorder is probably not genetic at all, but we have a piece of it,” Dr Drayna said.

“These genes are providing a lot of surprises. The genes we have found to date all control an aspect of cell metabolism that has been well known and studied by medical geneticists for 50 years but in a completely different context.

“These genes have been associated with very rare but lethal inherited diseases of children. So it was quite a surprise to see mutations in people who otherwise are completely normal, other than stuttering,” he said.

By generating mice with the same DNA mutations, the scientists hope to create the first animal “model” of human stuttering, which will be a vital tool both for understanding the speech impediment and for the development of potential drugs that could be used to treat it.

“Mice have an extremely rich vocal communication but it is extremely poorly understood right now – you can’t hear it because it’s too high pitched,” Dr Drayna said.

“What we are really looking for is an outward manifestation of the fact that these animals are carrying a mutation in these particular genes,” he told the American Association for the Advancement of Science in Washington.

“If we get some sort of alteration, then that opens up an enormous realm because the mouse is the standard mammalian laboratory organism, it is the standard model [for human disorders],” he said.

The genetic mutations, which are found in about 10 per cent of people with a family history of stuttering, were discovered by studies of extended families. These relatively minor mutations occur in three genes, which were already known to cause severe inherited disorders as a result of far more severe mutations that eliminate the gene’s function entirely.

“It’s just a hypothesis at this point but there is a class of cells in the brain, the neurons, that are exquisitely sensitive to this modest little metabolic deficit that is produced by these mutations and these neurons are dedicated uniquely to speech,” Dr Drayna said.

“Our goal is to find out what these cells are, what they are connected to, what their normal function is, and how that function goes awry when these mutations produce a relatively mild metabolic abnormality in those special cells,” he said.

Other studies by Dr Luc De Nil of the University of Toronto have shown higher-than-usual nerve activity in certain regions of the brain of people who stutter, which may be related to the genetic differences identified by Dr Drayna’s team.

“One very curious thing that people have been reporting is that while many of the areas of the brain are over-activated, there actually seems to be a deactivation or under activation of the auditory parts of the brain in people who stutter,” Dr De Nil said.

“I would be extremely surprised if some of the genetic research will not ultimately elucidate and clarify what we are finding,” he told the meeting.

Voices
voicesGood for Lana Del Rey for helping kill that myth, writes Grace Dent
Sport
The Pipes and Drums of The Scottish Regiments perform during the Opening Ceremony for the Glasgow 2014 Commonwealth Games at Celtic Park on July 23, 2014 in Glasgow, Scotland.
Commonwealth GamesThe actor encouraged the one billion viewers of the event to donate to the children's charity
Sport
Karen Dunbar performs
Entertainers showcase local wit, talent and irrepressible spirit
Sport
Members of the Scotland deleagtion walk past during the opening ceremony of the 2014 Commonwealth Games at Celtic Park in Glasgow on July 23, 2014.
PROMOTED VIDEO
Arts and Entertainment
The Tour de France peloton rides over a bridge on the Grinton Moor, Yorkshire, earlier this month
film
Life and Style
fashion Designs are part of feminist art project by a British student
News
Very tasty: Vladimir Putin dining alone, perhaps sensibly
news
Life and Style
Listen here: Apple EarPods offer an alternative
techAre custom, 3D printed earbuds the solution?
Arts and Entertainment
Top guns: Cole advised the makers of Second World War film Fury, starring Brad Pitt
filmLt-Col Steven Cole is the man Hollywood calls when it wants to borrow a tank or check a uniform
News
The University of California study monitored the reaction of 36 dogs
sciencePets' range of emotions revealed
News
Snoop Dogg pictured at The Hollywood Reporter Nominees' Night in February, 2013
people... says Snoop Dogg
News
ebookA unique anthology of reporting and analysis of a crucial period of history
Arts and Entertainment
A scene from Shakespeare in Love at the Noel Coward Theatre
theatreReview: Shakespeare in Love has moments of sheer stage poetry mixed with effervescent fun
News
Joining forces: young British men feature in an Isis video in which they urge Islamists in the West to join them in Iraq and Syria
newsWill the young Britons fighting in Syria be allowed to return home and resume their lives?
Arts and Entertainment
The nomination of 'The Wake' by Paul Kingsnorth has caused a stir
books
News
i100
Life and Style
food + drinkZebra meat is exotic and lean - but does it taste good?
Independent
Travel Shop
the manor
Up to 70% off luxury travel
on city breaks Find out more
santorini
Up to 70% off luxury travel
on chic beach resorts Find out more
sardina foodie
Up to 70% off luxury travel
on country retreats Find out more
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

BI Manager - £50,000

£49000 - £55000 per annum + competitive: Progressive Recruitment: My client is...

BI Project Manager - £48,000 - £54,000 - Midlands

£48000 - £54000 per annum + Benefits package: Progressive Recruitment: My clie...

VB.Net Developer

£35000 - £45000 per annum + competitive: Progressive Recruitment: If you're pa...

SAP Business Consultant (SD, MM and FICO), £55,000, Wakefield

£45000 - £55000 per annum + competitive: Progressive Recruitment: SAP Business...

Day In a Page

Screwing your way to the top? Good for Lana Del Rey for helping kill that myth

Screwing your way to the top?

Good for Lana Del Rey for helping kill that myth, says Grace Dent
Will the young Britons fighting in Syria be allowed to return home and resume their lives?

Will Britons fighting in Syria be able to resume their lives?

Tony Blair's Terrorism Act 2006 has made it an offence to take part in military action abroad with a "political, ideological, religious or racial motive"
Beyoncé poses as Rosie the Riveter, the wartime poster girl who became a feminist pin-up

Beyoncé poses as Rosie the Riveter

The wartime poster girl became the ultimate American symbol of female empowerment
The quest to find the perfect pair of earphones: Are custom, 3D printed earbuds the solution?

The quest to find the perfect pair of earphones

Earphones don't fit properly, offer mediocre audio quality and can even be painful. So the quest to design the perfect pair is music to Seth Stevenson's ears
US Army's shooting star: Lt-Col Steven Cole is the man Hollywood calls when it wants to borrow a tank or check a military uniform

Meet the US Army's shooting star

Lt-Col Steven Cole is the man Hollywood calls when it wants to borrow a tank or check a military uniform
Climate change threatens to make the antarctic fur seal extinct

Take a good look while you can

How climate change could wipe out this seal
Should emergency hospital weddings be made easier for the terminally ill?

Farewell, my lovely

Should emergency hospital weddings be made easier?
Man Booker Prize 2014 longlist: Crowdfunded novel nominated for first time

Crowdfunded novel nominated for Booker Prize

Paul Kingsnorth's 'The Wake' is in contention for the prestigious award
Vladimir Putin employs a full-time food taster to ensure his meals aren't poisoned

Vladimir Putin employs a full-time food taster

John Walsh salutes those brave souls who have, throughout history, put their knives on the line
Tour de France effect brings Hollywood blockbusters to Yorkshire

Tour de France effect brings Hollywood blockbusters to Yorkshire

A $25m thriller starring Sam Worthington to be made in God's Own Country
Will The Minerva Project - the first 'elite' American university to be launched in a century - change the face of higher learning?

Will The Minerva Project change the face of higher learning?

The university has no lecture halls, no debating societies, no sports teams and no fraternities. Instead, the 33 students who have made the cut at Minerva, will travel the world and change the face of higher learning
The 10 best pedicure products

Feet treat: 10 best pedicure products

Bags packed and all prepped for holidays, but feet in a state? Get them flip-flop-ready with our pick of the items for a DIY treatment
Commonwealth Games 2014: Great Scots! Planes and pipers welcome in Glasgow's Games

Commonwealth Games 2014

Great Scots! Planes and pipers welcome in Glasgow's Games
Jack Pitt-Brooke: Manchester City and Patrick Vieira make the right stand on racism

Jack Pitt-Brooke

Manchester City and Patrick Vieira make the right stand on racism
How Terry Newton tragedy made iron men seek help to tackle their psychological demons

How Newton tragedy made iron men seek help to tackle their psychological demons

Over a hundred rugby league players have contacted clinic to deal with mental challenges of game