The A1555G mtDNA mutation in Danish hearing-impaired patients: frequency and clinical signs.

The A1555G mutation of the mtDNA is associated with both aminoglycoside-induced and non-syndromic hearing loss. The A1555G is relatively frequent in the Spanish and some Asian populations, but has only been reported rarely in other populations, possibly because of ascertainment bias. We studied 85 Danish patients with varying degrees of hearing impairment and found two patients with the A1555G mutation (2.4%). Neither had received aminoglycosides. Our study indicates that the mutation might not be uncommon in Danish patients with hearing impairment.