Ear infections linked to genetics

Ear infections may run in families

A painful ear condition common in early childhood may run in families, a study in twins and triplets shows.

The study into middle ear infections, carried out over two years at the University of Pittsburgh School of Medicine, involved 135 sets of same sex twins and five sets of same sex triplets.

Margaretha Caselbrant, lead author of the research, said that for identical twins or triplets "if one child has ear disease, the likelihood of the other child having ear disease was about 60 per cent".

In non-identical twins the likelihood was around 30 per cent.

She suggests the findings could be used to encourage doctors to identify high risk cases earlier.

If one child has ear disease, the likelihood of the other child having ear disease was about 60 per cent

Margaretha Caselbrant

"Closer surveillance of patients at risk could result in earlier detection and treatment of the disease, as well as prevention of possible developmental problems," she said in the Journal of the American Medical Association.

Twin studies, particularly of identical - or monosygotic - pairs, are used in determining the role of genetics because they screen out environmental factors.

Confirms findings

Professor Mark Haggard, at the Medical Research Council's Institute of Hearing in Nottingham, said the Pittsburgh study confirms the findings of research currently underway there.

"Most conditions are weakly familial," he said. "It is not surprising that twins would be more similar then randomly selected children.

"The real question is how much more likely it is. If monosygotic twins are a whole lot more likely to display similar patterns of disease, then that would suggest it is strongly hereditary.

"Therefore, the genes for this vulnerability can be found. That is a very large part of the story."

Knowing that a child was susceptible to middle ear infections because of a family history of the condition would allow parents to control the child's environment, reducing its chances of becoming ill, he said.

Genetic testing has caused controversy in some cases because of the possibility that parents of an unborn child might choose to abort if they knew it was susceptible to a condition, but Professor Haggard said this was unlikely to be a factor in the case of middle ear infections.