A gene scorecard may one day help predict which youngsters
are likely to grow out of childhood asthma and which ones will have the disease in
adulthood, a study said on Thursday.
Asthma is one of the commonest disorders among children in
developed countries and is spreading fast in emerging economies.
Roughly half of children with asthma will emerge from it by
the time they become young adults – but until now, no-one knows how to
determine who will be the lucky ones.
The new research, published in The Lancet Respiratory
Medicine Journal, marks a first step towards a predictive test.
Researchers in the United States put together a risk score
derived from 15 genetic variants that are closely associated with asthma.
They tested this model on data from a highly-regarded,
long-running study in New Zealand, in which 880 people have been tracked for
health since their birth 40 years ago.
Those whose DNA carried most risk variants were more than a
third likelier to develop asthma earlier in life and to have asthma that
persisted into adulthood than those at low genetic risk.
A higher score also meant they were likelier to be prone to
asthma-related allergic reactions and impaired lung function. They were also
likelier to miss school or work than counterparts with a lower genetic risk.
The test is an initial foray into a complex disease believed
to have environmental and genetic factors, and for which more risk variants are
likely to emerge.
It could unlock better understanding of the biology of
asthma, notably how pollution and genes interact.
But it would have to be refined and widened to make it
useable in routine medical practice.
"As additional risk genes are discovered, the value of
genetic assessments is likely to improve. But our predictions are not
sufficiently sensitive or specific to support their use in routine clinical
practice," said study leader Daniel Belsky from Duke University, at
Durham, North Carolina.