Persistent asthma later in life linked to high number of risk genes

Asthmatics carrying several genetic variations associated with asthma are more likely to develop severe, longer lasting disease, research shows.

The findings show that those with high genetic risk scores are more than a third more likely to develop life-long asthma than asthmatics with low scores. Despite this, the researchers say that any genetic test to predict severity of asthma looks a long way off.

For the study, scientists drew on previous research; they used the largest current study of asthma-associated genetic variations to define a genetic risk score for asthma, then applied that to a 40-year New Zealand study that has followed over 1,000 people since birth, monitoring their health.

Fifteen locations in the genome were included in the score, with particular changes (or 'polymorphisms') at each location contributing to the risk. People with higher scores were more likely to develop asthma earlier in life, and for that asthma to persist throughout life.

Higher risk scores also correlated with more severe disease, with these patients being shown to have higher rates of asthma-related absence from work or school and increased risk of being hospitalised due to their condition.

These findings suggest that genetic tests might be useful in asthmatic children to assess the chances of their condition continuing into later life. However, lead author Dr Daniel Belsky from Duke University in the USA cautioned that 'genetic risk prediction for asthma is still in its infancy'.

He further confirmed that his team's 'predictions are not sufficiently sensitive or specific to support their immediate use in routine clinical practice'.

All the same, in a summary accompanying the paper, Dr Belsky points out that this work is in line with previous research, showing that such genetic risks can have 'real-life consequences'.

Talking to the BBC, Leanne Reynolds from Asthma UK added: 'This could mean that in the future we're able to identify those people whose asthma will put them at greatest risk so we can ensure they get the support they need'.

The study was published in The Lancet Respiratory Medicine.