Genetic testing could predict asthma persistence
medwireNews: Research suggests that genetic risk assessment could be used to predict whether a child's asthma will persist into adulthood.
Results from a 40-year birth cohort study, published in TheLancet Respiratory Medicine, show that children with multiple asthma-associated alleles were significantly more likely to still have asthma as adults than children with fewer risk alleles.
Researchers Daniel Belsky (Duke University Medical Center, Durham, North Carolina, USA) and team genotyped 880 members of the Dunedin study cohort from New Zealand at the age of 38 years. The participants, who have been assessed periodically since the age of 9 years, were tested for 15 single nucleotide polymorphisms that were identified in the largest genome-wide association study in asthma to date, to create an individual risk score out of 30.
In all, 187 (21%) children developed asthma before the age of 13 years, and 96 (11%) had life-course-persistent asthma, the risk for which was 36% greater for each standard deviation (SD) increase in risk score (equivalent to 4.36 more risk alleles).
And the authors found that children with higher risk scores were not only significantly more likely to develop asthma during follow up than those with lower genetic risk, but they were also more likely to develop it earlier in life.
Children with higher risk also appeared to have a distinct phenotype of atopic asthma characterized by airway hyperresponsiveness, and incompletely reversible airway obstruction, the authors note.
Additionally, the team found that the impact of asthma on daily life was worse in higher risk children who, for each SD increase in risk score, had 38% more incidences of missed school or work attendance due to asthma, and were 38% more likely to be admitted to hospital with breathing problems.
Importantly, aside from the incidence of days of school missed due to asthma, all of the associations remained significant after adjusting for family history of asthma, showing that genetic risk added information to prediction models over and above family history. Moreover, there was in fact a poor correlation between genotypic risk and that based on family history.
Despite their promising findings, however, the authors caution that their predictions are not yet sufficiently specific or sensitive for use in routine clinical practice.
"Although our study revealed that genetic risks can help to predict which childhood-onset asthma cases remit and which become life-course-persistent, genetic risk prediction for asthma is still in its infancy," explained Belsky in a press statement.
He added: "As additional risk genes are discovered, the value of genetic assessments is likely to improve."
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By Kirsty Oswald, medwireNews Reporter