Malaria deaths are linked to genetic traits

PEOPLE may die from infectious disease not because the infection is particularly virulent, but because their own genes have marked them down.

According to Dr Bill McGuire, of the Institute of Molecular Medicine in Oxford, children living in The Gambia, West Africa, who have inherited a particular combination of genes from their parents are seven times more likely to die after infection with malaria than children with different genes. Paradoxically, the 'risky' genes are responsible for producing higher levels of a molecule which normally stimulates the immune system's defences against infection.

Susceptibility to tuberculosis and leprosy may also be influenced in the same way, Dr McGuire said. Following publication of the malaria study in today's issue of the scientific journal Nature, the researchers will now be tracking the genetic response to these diseases.

Almost 2 million people die each year from malaria, usually from the severest form which affects the brain and is known as cerebral malaria. About half a million children die of cerebral malaria each year in Africa alone.

The team of researchers, led by Dr Dominic Kwiatkowski also of the institute, conducted a case- controlled study in the late 1980s of more than 1,000 children in The Gambia, where the UK's Medical Research Council runs an internationally renowned laboratory. Dr McGuire said: 'Most children in The Gambia suffer malaria infection at some time in the year, but only a small fraction of them die. The most common fatal complication is cerebral malaria.'

When the malaria parasites invade the body, they trigger the infected person to make molecules which activate the immune system but which also cause many of the symptoms of infection such as aches and fever. Particularly important in malaria is Tumor Necrosis Factor (TNF) which helps fight the infection by causing the high temperatures - the raging fevers familiarly associated with malaria. These high temperatures damage the parasites.

But according to Dr McGuire, TNF also makes the inner lining of the blood vessels sticky to blood cells laden with malaria parasites. In cerebral malaria, the blood supply to the brain may be choked off because the blood vessels supplying the brain get congested.

Last year, researchers in Sheffield announced that they had discovered two different variants of the gene responsible for producing TNF. One variant could lead to excessive production of TNF. This sent Dr Kwiatkowski and his colleagues back to their deep freezes where they had stored DNA, taken in the form of blood samples from Gambian children.

The reseachers found that a child who inherited two copies of the high-production variant - one each from their mother and father - was seven times more likely to develop cerebral malaria than those who had inherited just one copy or none at all.

'Normally, the TNF response is a good thing, to activate the immune system,' Dr McGuire said. However, having an overactive immune system may be a bad thing. 'TNF probably contributes to fevers and the bodily wasting in tuberculosis,' he continued, and the way in which an infected person responds to TB may determine whether the illness is slight or severe and chronic.

However, Dr McGuire said that the gene is widespread in the Gambian population which suggests that it may confer other, as yet unknown advantages, in combating other diseases.

Start your day with The Independent, sign up for daily news emails
News
Young Winstone: His ‘tough-guy’ image is a misconception
people
Sport
Adnan Januzaj and Gareth Bale
footballManchester United set to loan out Januzaj to make room for Bale - if a move for the Welshman firms up
Arts and Entertainment
Ellie Levenson’s The Election book demystifies politics for children
bookNew children's book primes the next generation for politics
News
Outspoken: Alexander Fury, John Rentoul, Ellen E Jones and Katy Guest
newsFrom the Scottish referendum to the Ice Bucket Challenge, our writers voice their opinions
PROMOTED VIDEO
Have you tried new the Independent Digital Edition apps?
ebooks
ebooksA year of political gossip, levity and intrigue from the sharpest pen in Westminster
News
i100
Sport
Yaya Sanogo, Mats Hummels, Troy Deeney and Adnan Januzaj
footballMost Premier League sides are after a striker, but here's a full run down of the ins and outs that could happen over the next month
Arts and Entertainment
L to R: Hawkeye (Jeremy Renner), Captain America (Chris Evans) & Black Widow (Scarlett Johansson) in Avengers Assemble
film
News
Nigel Farage celebrates with a pint after early local election results in the Hoy and Helmet pub in South Benfleet in Essex
peopleHe has shaped British politics 'for good or ill'
Arts and Entertainment
Pharrell Williams' “Happy” was the most searched-for song lyric of 2014
musicThe power of song never greater, according to our internet searches
Sport
Tim Sherwood raises his hand after the 1-0 victory over Stoke
footballFormer Tottenham boss leads list of candidates to replace Neil Warnock
Arts and Entertainment
Sink the Pink's 2013 New Year's Eve party
musicFour of Britain's top DJs give their verdict on how to party into 2015
Voices
Strictly Come Dancing was watched by 6.9m viewers
voicesIt has been hard to form generally accepted cultural standards since the middle of the 19th century – and the disintegration is only going to accelerate, says DJ Taylor
Arts and Entertainment
Roffey says: 'All of us carry shame and taboo around about our sexuality. But I was determined not to let shame stop me writing my memoir.'
books
News
i100
News
Caplan says of Jacobs: 'She is a very collaborative director, and gives actors a lot of freedom. She makes things happen.'
people
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

Selby Jennings: VP/SVP Credit Quant- NY- Investment Bank

Not specified: Selby Jennings: VP/SVP Credit Quant Top tier investment bank i...

Ashdown Group: Senior Marketing Executive- City of London, Old Street

£40000 - £43000 per annum + benefits: Ashdown Group: Senior Marketing Executiv...

Ashdown Group: Marketing Manager

£40000 - £43000 per annum + benefits: Ashdown Group: An international organisa...

Ashdown Group: Internal Recruiter -Rugby, Warwickshire

£25000 - £30000 per annum: Ashdown Group: Internal Recruiter -Rugby, Warwicksh...

Day In a Page

War with Isis: The West needs more than a White Knight

The West needs more than a White Knight

Despite billions spent on weapons, the US has not been able to counter Isis's gruesome tactics, says Patrick Cockburn
Return to Helmand: Private Davey Graham recalls the day he was shot by the Taliban

'The day I was shot by the Taliban'

Private Davey Graham was shot five times during an ambush in 2007 - it was the first, controversial photograph to show the dangers our soldiers faced in Helmand province
Revealed: the best and worst airlines for delays

Revealed: the best and worst airlines for delays

Many flyers are failing to claim compensation to which they are entitled, a new survey has found
The stories that defined 2014: From the Scottish independence referendum to the Ice Bucket Challenge, our writers voice their opinions

The stories that defined 2014

From the Scottish independence referendum to the Ice Bucket Challenge, our writers voice their opinions
Stoke-on-Trent becomes first British city to be classified as 'disaster resilient' by the United Nations

Disaster looming? Now you know where to head...

Which British city has become the first to be awarded special 'resilience' status by the UN?
Finally, a diet that works: Californian pastor's wildly popular Daniel Plan has seen his congregation greatly reduced

Finally, a diet that works

Californian pastor's wildly popular Daniel Plan has seen his congregation greatly reduced
Say it with... lyrics: The power of song was never greater, according to our internet searches

Say it with... lyrics

The power of song was never greater, according to our internet searches
Professor Danielle George: On a mission to bring back the art of 'thinkering'

The joys of 'thinkering'

Professor Danielle George on why we have to nurture tomorrow's scientists today
Monique Roffey: The author on father figures, the nation's narcissism and New Year reflections

Monique Roffey interview

The author on father figures, the nation's narcissism and New Year reflections
Introducing my anti-heroes of 2014

Introducing my anti-heroes of 2014

Their outrageousness and originality makes the world a bit more interesting, says Ellen E Jones
DJ Taylor: Good taste? It's all a matter of timing...

Good taste? It's all a matter of timing...

It has been hard to form generally accepted cultural standards since the middle of the 19th century – and the disintegration is only going to accelerate, says DJ Taylor
Olivia Jacobs & Ben Caplan: 'Ben thought the play was called 'Christian Love'. It was 'Christie in Love' - about a necrophiliac serial killer'

How we met

Olivia Jacobs and Ben Caplan
Bill Granger recipes: Our chef's breakfasts will revitalise you in time for the New Year

Bill Granger's healthy breakfasts

Our chef's healthy recipes are perfect if you've overindulged during the festive season
Transfer guide: From Arsenal to West Ham - what does your club need in the January transfer window?

Who does your club need in the transfer window?

Most Premier League sides are after a striker, but here's a full run down of the ins and outs that could happen over the next month
The Last Word: From aliens at FA to yak’s milk in the Tour, here’s to 2015

Michael Calvin's Last Word

From aliens at FA to yak’s milk in the Tour, here’s to 2015