Genetic Signature To Test For Childhood TB

Scientists hope that with a better method for diagnosing TB in children, the disease will be caught at an earlier stage and damage will be reduced.

AsianScientist (May 9, 2014) – A distinctive genetic “signature” offers new hope for developing a rapid, affordable diagnostic test for the hundreds of thousands of children infected with tuberculosis each year.

The team that made the discovery included Dr. Lachlan Coin from The University of Queensland’s Institute for Molecular Bioscience (IMB) and Dr. Martin Hibberd from the Genome Institute of Singapore.

The five-year study was conducted by an international consortium of investigators from the UK, Africa, Australia and Singapore, who studied more than 2,800 children admitted to hospitals in South Africa, Malawi and Kenya with symptoms of TB.

“We urgently need better methods to diagnose TB in children,” said Professor Michael Levin from Imperial College London, who led the study. “These will allow treatment to begin earlier and avoid unnecessary treatment of children who are wrongly diagnosed.

“The symptoms of TB in children are common to many other childhood diseases, and the standard tests used on adults are not effective in children. Although the disease is treatable, thousands of children still die each year due to late diagnosis and many more are left with damage to their brain, bones and lungs.”

The discovery of the gene expression signature in the blood of children with TB was published in the New England Journal of Medicine.

Researchers found the signature by examining which genes were activated or suppressed in blood samples from African children with a confirmed diagnosis of TB. They compared these patterns to those found in children with other diseases similar to TB and identified an expression signature of 51 genes indicative of active TB.

“One of the main challenges was to distinguish TB from other infectious diseases, because the baseline inflammatory response to infection means that the difference in signatures is more subtle than between TB and healthy controls,” Coin said.

“We also wanted to find the smallest number of genes needed to measure to diagnose active TB. A test that surveys fewer genes costs less. This is an important consideration given the majority of children with TB live in developing nations.”

The next step for the researchers is to turn their findings into an affordable, rapid test for TB that can be used worldwide.

Coin also hopes to secure funding to trial the test in Papua New Guinea, where TB is estimated to be the largest cause of infectious disease mortality.

The article can be found at: Anderson et al. (2014) Diagnosis of Childhood Tuberculosis and Host RNA Expression in Africa.


Source: University of Queensland; Photo: isafmedia/Flickr/CC.

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