[Mitochondrial A1555G mutation. Molecular genetic diagnosis in sporadic cases of non-syndromic hearing impairment].
BACKGROUND
The A1555G mutation in mitochondrial DNA is the cause of hearing impairment in about 50% of all carriers. The severity and onset of this impairment is predominantly affected by the use of aminoglycosides.


METHODS
A total of 391 patients displaying sporadic, non-syndromic, mild to severe hearing impairment were analyzed for the A1555G mutation using molecular genetic methods.


RESULTS
We analysed additional family members of the two patients (0.5% of the total) who had the mutation. All maternal relatives carried the mutation, but only three individuals from the two families displayed a variable sensorineural hearing loss.


CONCLUSIONS
The A1555G mutation is infrequently involved as a genetic cause of sporadic, non-syndromic hearing impairment. Nevertheless, based on the variable clinical outcome of hearing impairment and the possibility of preventive steps, a genetic test in this patient subgroup is indicated.
Hals-Nasen-Ohren-Klinik der Universität Tübingen.
S
S
Kupka
B
B
Bodden-Kamps
M
M
Baur
H P
HP
Zenner
M
M
Pfister
D004252:DNA Mutational Analysis / Q000379:methods; D004272:DNA, Mitochondrial / Q000235:genetics; D020022:Genetic Predisposition to Disease / Q000453:epidemiology*; D005820:Genetic Testing / Q000379:methods*; D005858:Germany / Q000453:epidemiology; D034381:Hearing Loss / Q000453:epidemiology* / Q000235:genetics*; D006801:Humans; D008297:Male; D009154:Mutation; D010375:Pedigree; D011110:Polymorphism, Genetic; D012335:RNA, Ribosomal / Q000235:genetics*; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors
D004272:DNA, Mitochondrial; D012335:RNA, Ribosomal; C075526:RNA, ribosomal, 12S