A guideline from the UK Centre of Excellence in Regulatory Science and Innovation in Pharmacogenomics sets out how to use MT-RNR1 genotyping to prevent aminoglycoside ototoxicity.
Three mitochondrial variants (m.1555A>G, m.1494C>T and m.1095T>C), found in about 1 in 330 people across populations, predispose to irreversible sensorineural hearing loss after aminoglycoside exposure, sometimes after one dose. The guideline recommends avoiding aminoglycosides at any detectable variant level. About 20% of aminoglycoside use is predictable, allowing pre-emptive testing. Where urgency is high and no result is available, treatment should not be delayed. Early economic evidence suggests point-of-care testing in neonates may be cost-saving.
Ototoxicity from aminoglycosides has been treated as unpredictable. For carriers of these variants it is predictable, and the hearing loss is lifelong.
In England, laboratory testing is nationally commissioned. Testing availability in India is not established, although aminoglycosides are widely used in neonatal and tuberculosis care, so a family history of aminoglycoside-related deafness is currently the most practical screen.
- Ask about maternal-line family history of hearing loss after antibiotics before planned aminoglycoside courses.
- Where testing is available, genotype before elective or predictable use such as cystic fibrosis or prolonged TB therapy.
- Never delay aminoglycosides in sepsis while waiting for a result.
- If a variant is found, record it prominently and inform maternal relatives, who share mitochondrial DNA.
- Consider audiology referral for children with hearing loss and past aminoglycoside exposure.
Why it matters
It turns a large share of aminoglycoside ototoxicity from an unforeseeable side effect into a preventable one.
Don't overread it
The cost-effectiveness evidence is early and mainly neonatal; the guideline does not support delaying life-saving antibiotics for testing.
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