Gene fault puts children's hearing at risk

6 February 2009

Antibiotics used in some hospital settings seriously damage the hearing of children with a relatively common genetic mutation.

Aminoglycosides are used to treat serious infection and are known to have damaging effects on hearing and kidney function. As a result the dose is closely monitored to stay within recommended safe levels.

But some children inherit a mutation in the m.1555A>G gene that means their risk of developing hearing loss from use of aminoglycosides is high, even when using doses considered low in other children.  

The research, from the UCL Institute of Child Health and published in the New England Journal of Medicine, found that the mutation occurred in one in 500 of the 9, 371 children tested.

Dr Maria Bitner-Glindzicz, an Adviser to Deafness Research UK and one of the study’s lead authors said:

“These antibiotics are widely used on very sick children. They are cheap and effective. We believe that it will be cost effective to genetically screen groups of patients who will almost certainly receive aminoglycoside antibiotics, to see if they carry the mutation, before administering the antibiotics. This will allow an alternative antibiotic to be given to anyone who has the mutation.

“In some groups of patients, such as those with leukaemia or cystic fibrosis, there is a window of opportunity to perform genetic testing before the need for antibiotics arises.  The difficulty will be when the matter is clinically urgent, because of the time it currently takes to get the genetic results. 

“Waiting for a gene test may sometimes not be clinically right.  This is particularly likely to be an issue on neonatal units. Universal pre-natal testing of mothers should be considered for this reason, but these options need to be nationally evaluated.

“There needs to be clear professional guidance for doctors, and health advice for families.”

The group of children studied in the current research was largely Caucasian.  Prevalence rates in non-Caucasian populations are not known.

The journal also publishes an Australian study in adults which confirms a similar prevalence of the mutation to the UK study.