Clinical and audiological follow up of a family with the 8363G>A mutation in the mitochondrial DNA.
Hearing loss is relatively common in mtDNA-related disorders. While auditory function has been assessed fully in the syndrome of mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes, few studies have investigated the degree of progressive hearing deficit in individuals bearing other mtDNA mutations. We performed a 4-year clinical and audiological follow up in a family carrying the 8363G>A mutation in the mitochondrial transfer ribonucleic acid lysine (tRNA(Lys)) gene who displayed a progressive neuromuscular disease. In addition to pure tone audiometry, we considered distortion products of otoacoustic emissions, a sensitive indicator of cochlear dysfunction, as well as brainstem auditory evoked responses. A generalized increase in the auditory threshold at follow up, indicating a cochlear impairment in three cases, was noted. Distortion products of otoacoustic emissions may reveal sub-clinical cochlear dysfunction, even in oligosymptomatic patients. A complete and periodical assessment of the hearing function should be encouraged in asymptomatic relatives of patients carrying the tRNA(Lys) 8363G>A mutation.
DiFabio
Roberto
R
Department of Neurology and ORL, Sapienza University of Rome ICOT, Polo Pontino, 04100 Latina, Italy. rob.dif@tiscali.it
Santorelli
Filippo M
FM
Nola
Giuseppe
G
Cricchi
Federica
F
Masi
Roberto
R
Ingrosso
Angelo
A
Fattori
Fabiana
F
Carrozzo
Rosalba
R
Vanacore
Nicola
N
Pierelli
Francesco
F
Ralli
Giovanni
G
Casali
Carlo
C
D000328:Adult; D000368:Aged; D001299:Audiometry; D001309:Auditory Threshold / Q000502:physiology; D003051:Cochlea / Q000378:metabolism / Q000503:physiopathology; D015897:Comorbidity; D004252:DNA Mutational Analysis; D018450:Disease Progression; D016057:Evoked Potentials, Auditory, Brain Stem / Q000235:genetics; D005260:Female; D005500:Follow-Up Studies; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D005820:Genetic Testing; D005838:Genotype; D006319:Hearing Loss, Sensorineural / Q000235:genetics* / Q000378:metabolism / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D028361:Mitochondrial Diseases / Q000235:genetics* / Q000378:metabolism / Q000503:physiopathology; D009154:Mutation / Q000235:genetics*; D009468:Neuromuscular Diseases / Q000235:genetics* / Q000378:metabolism / Q000503:physiopathology; D011237:Predictive Value of Tests; D012357:RNA, Transfer, Lys / Q000235:genetics*
D012357:RNA, Transfer, Lys