Mitochondrial Genetics of Presbycusis

Study Overview
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Brief Summary
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The main goal of this study is to identify mitochondrial mutations associated with presbycusis. Patients affected by severe presbycusis and normal hearing controls (according to ISO7029 norm) will be enrolled if satisfying inclusion criteria (aged from 40 to 80 years old) in existing biocollections in the University Hospital of Angers. After DNA extraction, the mitochondrial genome will be sequenced and data in silico analysed.

Detailed Description
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The study will be proposed to patients consulting in the ENT department of the University Hospital of Angers. After clinical examination and audiometry recording, the eligibility criteria will be checked and inclusion in biocollections proposed. Presbycusis affected subjects will be enrolled in Mitochondrial Disease biocollection and normal hearing controls in Healthy Volunteer biocollection. These biocollections have been approved by the board comitee Centre de Protection des Personnes. After DNA extraction and mitochondrial sequencing, candidate variants will be selected by in silico analysis. The presence of mitochondrial variants in both groups (presbycusis and control) will be compared in multivariate analysis if needed. The nuclear DNA may be sequenced in order to complete the previous analysis and look for any candidate variant .

Official Title
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Mitochondrial Genetics of Presbycusis

Conditions
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Presbycusis, Age Related Hearing Loss

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: age related hearing loss more severe than the predicted hearing thresholds according to the norm ISO7029, for the presbycusis population; normal hearing according to norm ISO7029 for the control population Exclusion Criteria: deafness diagnosed before 40 years old exclusion criteria of one of the biocollection

Ages Eligible for Study
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Minimum Age: 40 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| presbycusis affected patients<br>affected by a more severe age related hearing loss than expected according to the norm ISO 7029 | |
| controls<br>not affected by age related hearing loss according to the norm ISO 7029 | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| identification of mitochondrial mutations associated with presbycusis | Enrichment analysis will be perfomed with CHI2 test after Benjamini correction. | the analysis will be conducted at the end of the inclusion of the 200 patients | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| identification of genomic variants associated with presbycusis | enrichment of genomic variants will be analysed | the analysis will be conducted at the end of the inclusion of the 200 patients | 
| identification of DNA variants associated with environmental susceptibility | subgroup analysis will be performed in accordance with environmental exposition | the analysis will be conducted at the end of the inclusion of the 200 patients |