| Project/Area Number |
07044215
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | Joint Research |
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| Research Institution | Hirosaki University |
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Principal Investigator |
SHINKAWA Hideichi School of Medicine, Hirosaki University, Professor, 医学部, 教授 (90125584)
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| Co-Investigator(Kenkyū-buntansha) |
キンバーリング ウイリア ボーイズタウン国立研究病院, 教授
USAMI Shinichi School of Medicine, Hirosaki University, 医学部, 助教授 (10184996)
KIMBERLING W.J Boys Town National Research Hospital
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| Project Period (FY) |
1995 – 1996
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| Project Status |
Completed (Fiscal Year 1996)
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| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 1996: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1995: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Keywords | hearing loss / genetics / mitochondrial DNA / recessive / (遺伝性)難聴 / 遺伝子 |
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| Research Abstract |
Joint Study on Genetic Analysis of Hereditary Hearing Loss
Mitochondrial mutations are known to be one of the causes of non-syndromic sensorineural hearing loss (SNHL). Among them, a 1555A->G mutation has been reported to cause susceptibility to aminoglycoside antibiotics. In the present study, thirteen Japanese families showing 1555A->G mutation were genetically as well as clinically investigated. The regional predominance has lead us to examine the evolution of mutant mitochondrial DNA by comparing polymorphisms found in different Japanese families. Restriction enzyme analysis revealed several polymorphisms of mtDNA in these pedigrees. No specific mutation having a possible relation to hearing impairment except for 1555A->G was found among the mutations studied. The D-loop sequence together with the mtDNA RFLP variation and 9 bp deletion showed identical patterns regarding mutations between the three families, indicating that each group may possibly have had a common ancestor. Many su
… More
bjects who harbor this mitochondrial mutation exhibit a mild, high frequency, progressive hearing loss even without aminoglycoside injection. Regardless of amminoglycoside exposure, hearing loss was usually associated with permanent tinnitus. The results presented here appear to support the hypothesis that the A 1555G mutation may play a more general role in causing hearing loss.
Hereditary hearing loss patients whose inheritance seems to be autosomal recessive in Aomori Prefecture (Northern Japan) were surveyed. Three phenotypically distinct categories of recessive hearing loss, profound, high frequency, and moderate, could be identified. The most common type, which is high frequency progressive hearing loss seems to be somewhat unique in this area, suggestiong a new gene may be involved.
We describes three familial cases of recessive hereditary hearing loss associated with enlargement of the vestibular aqueduct (EVA). These cases suggested EVA may be a useful discriminator between different types of recessive hearing loss. We are currently searching the responsible gene for this type of hearing loss. Less
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