Can a gene test flag hearing damage risk before a certain antibiotic?

What the test looks for

Aminoglycosides are a family of powerful broad-spectrum antibiotics used to treat severe infections. In a small number of people, these drugs can cause permanent hearing damage, and this risk is not reliably predicted by the dose. The gene test checks for inherited spelling changes that make a person especially vulnerable to this harm.

The test looks at a gene called MT-RNR1 for three specific inherited spelling changes: m.1555A>G, m.1494C>T and m.1095T>C. These changes are present in about one in 330 people across populations. When a person with one of these changes receives an aminoglycoside, the result can be permanent hearing loss, sometimes after a single dose.

How the guidance works

The guideline recommends avoiding aminoglycoside antibiotics whenever any of these changes is detected, at any detectable variant level. This means choosing a different antibiotic when one is available and appropriate for the infection.

When not to wait

There is an important exception. When someone has a serious infection and MT-RNR1 test results are not available, urgent treatment with an aminoglycoside should not be delayed. Waiting for a gene test could be more dangerous than the hearing risk, especially when the infection is life-threatening.

Where this guidance stops

This advice is part of a guideline developed by UK experts in pharmacogenomics—the use of genetic information to guide medication choices. The authors say it cannot account for all individual factors, so prescribers must still assess each person’s risk and benefit. The aim is to reduce harm while preserving access to life-saving antibiotic treatment.