[Mitochondrial DNA mutations in matrilineal nonsyndromic deafness pedigrees of southwest China].

OBJECTIVE

To identify the incidence of the 1555A-->G mutation and explore the audiological features of pedigrees with matrilineal non-syndromic deafness in Southwest of China so as to provide the theoretical evidence for establishing the method of gene diagnosis.

METHODS

Six pedigrees with 102 members were evaluated audiologically and clinically. DNA was extracted from their blood samples. All subjects were screened for mitochondrial DNA 1555A-->G mutation by Alw 26I restriction endonuclease digestion.

RESULTS

Seventeen maternal relatives of aminoglycoside antibiotic induced deafness (AAID) pedigree 1 and pedigree 2, carried 1555A-->G mutation. 10 maternal relatives of Non-AAID pedigree 6 also carried 1555A-->G mutation. No mutation was found among paternal relatives and pedigrees 3, 4 and 5.

CONCLUSION

The same audiological features of these pedigrees are: bilateral and symmetrical progressive sensorineural hearing loss with variable age of onset. The 1555A-->G mitochondrial mutation is one of the hereditary factors for this disorder. 4 Aminoglycoside antibiotic plays an important role in developing deafness. The incidence of the 1555A-->G mutation in AAID and matrilineal non-syndromic deafness pedigrees is fairly high. Screening for mitochondrial 1555A-->G mutation may be of great clinical use fullness.