Genetic test for asthma may improve treatment

Testing children with asthma for a variant in the beta-2 receptor gene may help clinicians determine the most suitable medication, especially in children who respond poorly to standard treatment.

The researchers, from the University of Dundee and the Brighton and Sussex Medical School, said that the results were 'a step towards personalised and tailored medicine for asthma'.

The arginine-16 genotype of the beta-2 receptor gene is carried by one in seven asthma sufferers. The usual treatment for children where standard treatment with a reliever inhaler is not effective is a combination of a steroid inhaler and salmeterol, which is a beta receptor stimulant. However, previous studies have shown that people with the gene variant may respond poorly to salmeterol and there have been concerns that this drug may even make their symptoms worse.

With this is mind, the researchers decided to test whether children with the arginine-16 variant would respond better to an alternative treatment called Montelukast (also known as Singulair). Sixty-two children agreed to take part in the study and were randomly separated into two groups. The first received the standard treatment of fluticasone (a steroid inhaler) and salmeterol, and the second group received fluticasone and Montelukast. The participants were then followed up every three months over the course of a year.

The study showed that the number of school days missed over the year was found to be significantly lower in the Montelukast group. The researchers also looked at asthma exacerbations, salbutamol use, asthma symptom scores, lung function and quality of life scores.

Professor Somnath Mukhopadhyay of the Brighton and Sussex Medical School, who was involved in the study, said: 'For almost every symptom we were looking at there was a significant difference and it was always in the favour of Montelukast' — although there was no observed significant difference in lung function between the two groups.

The researchers concluded that asthmatic children with this specific genetic variation 'appear to fare better on Montelukast than salmeterol' when this is combined with a corticosteroid. They added that treatment of these children may be made more effective with the help of a simple relatively inexpensive genetic test.

Malayka Rahman from Asthma Research UK said: 'This exciting area of research has the potential to lead to the tailoring of better treatments for an individual based on their genetic make-up, ultimately keeping more people out of hospital and preventing unnecessary asthma deaths in the long term'.

The present research was a proof of principle study to determine if an alternative treatment was more successful in certain patients and, as such, had a very small sample size of people with a known genetic variant. The results will therefore need to be confirmed in larger studies before changes in treatment regimen can be decided upon.