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
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

Recruitment Genius: Online Sales and Customer Services Executive

£15000 - £18000 per annum: Recruitment Genius: An On-line Sales & Customer Ser...

Recruitment Genius: Accounts Assistant - Fixed Term Contract - 6 Months

£15000 per annum: Recruitment Genius: One of the largest hospitality companies...

Recruitment Genius: Electricians - Fixed Wire Testing

£28000 - £32000 per annum: Recruitment Genius: As a result of significant cont...

Recruitment Genius: Customer Service Advisor

£16575 - £19000 per annum: Recruitment Genius: An excellent opportunity is ava...

Day In a Page

How to stop an asteroid hitting Earth: Would people co-operate to face down a global peril?

How to stop an asteroid hitting Earth

Would people cooperate to face a global peril?
Just one day to find €1.6bn: Greece edges nearer euro exit

One day to find €1.6bn

Greece is edging inexorably towards an exit from the euro
New 'Iron Man' augmented reality technology could help surgeons and firefighters, say scientists

'Iron Man' augmented reality technology could become reality

Holographic projections would provide extra information on objects in a person's visual field in real time
Sugary drinks 'are killing 184,000 adults around the world every year'

Sugary drinks are killing 184,000 adults around the world every year

The drinks that should be eliminated from people's diets
Pride of Place: Historians map out untold LGBT histories of locations throughout UK

Historians map out untold LGBT histories

Public are being asked to help improve the map
Lionel, Patti, Burt and The Who rock Glasto

Lionel, Patti, Burt and The Who rock Glasto

This was the year of 24-carat Golden Oldies
Paris Fashion Week

Paris Fashion Week

Thom Browne's scarecrows offer a rare beacon in commercial offerings
A year of the caliphate:

Isis, a year of the caliphate

Who can defeat the so-called 'Islamic State' – and how?
Marks and Spencer: Can a new team of designers put the spark back into the high-street brand?

Marks and Spencer

Can a new team of designers put the spark back into the high-street brand?
'We haven't invaded France': Italy's Prime Minister 'reclaims' Europe's highest peak

'We haven't invaded France'

Italy's Prime Minister 'reclaims' Europe's highest peak
Isis in Kobani: Why we ignore the worst of the massacres

Why do we ignore the worst of the massacres?

The West’s determination not to offend its Sunni allies helps Isis and puts us all at risk, says Patrick Cockburn
7/7 bombings 10 years on: Four emergency workers who saved lives recall the shocking day that 52 people were killed

Remembering 7/7 ten years on

Four emergency workers recall their memories of that day – and reveal how it's affected them ever since
Humans: Are the scientists developing robots in danger of replicating the hit Channel 4 drama?

They’re here to help

We want robots to do our drudge work, and to look enough like us for comfort. But are the scientists developing artificial intelligence in danger of replicating the TV drama Humans?
Time to lay these myths about the Deep South to rest

Time to lay these myths about the Deep South to rest

'Heritage' is a loaded word in the Dixie, but the Charleston killings show how dangerous it is to cling to a deadly past, says Rupert Cornwell
What exactly does 'one' mean? Court of Appeal passes judgement on thorny mathematical issue

What exactly does 'one' mean?

Court of Appeal passes judgement on thorny mathematical issue