MTRNR1
The Clinical Diagnostics Service of the Molecular Otolaryngology Research Laboratory is a Joint Commission-approved CLIA-accredited diagnostic laboratory that offers mutation screening of several genes.

MTRNR1 (OMIM# 561000)
Hearing loss as a result of aminoglycoside exposure (OMIM# 580000) has been reported to involve at least 2 mitochondrial mutations, C1494T and A1555G of the 12S rRNA gene. Damage to the inner ear is caused by reactive oxygen species, which provide a common pathway not only for aminoglycoside toxicity, but also for cisplatin toxicity and noise-induced hearing loss.  MORL offers screening for both of these mutations.

MORL screening methodology
Samples are amplified with an oligonucleotide primer pair that flanks the A1555G and C1494T mutations within the MTRNR1 gene, followed by sequencing.

Sensitivity
Sensitivity is greater than 99%.

Turn-around time
Turn around time is approximately 3 months.

Cost: $150

Indications for screening
This test is appropriate if aminoglycoside-induced ototoxcicity is suspected.

GeneTests  GeneReviews – Nonsyndromic Hearing Loss, Mitochondrial

References
Casano, R. A. et al.: Hearing loss due to the mitochondrial A1555G mutation in Italian families. Am J Med Genet. 79(5):388-91, 1998.
PubMed ID:  9779807 
PubMed Search

Zhao, H. et al: Maternally inherited aminoglycoside-induced and nonsyndromic deafness is associated with the novel C1494T mutation in the mitochondrial 12S rRNA gene in a large Chinese family. Am. J. Hum. Genet. 74: 139-152, 2004.
PubMed ID: 14681830
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