The invention relates to methods and kits for determining the presence of a mutation selected from the group consisting of 1555A>G and 1494C>T in human Mitochondrially Encoded 12S RNA (MTRNR1) gene in a sample from a subject, comprising, inter alia, amplifying at least part of the MTRNR1 gene and detecting the amplified DNA with a plasmonic gold nanoparticle covalently coupled to a morpholino oligonucleotide probe. The claimed method may be used for determining the risk of a subject to Aminoglycoside-induced hearing loss.