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.

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 .

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

The study is proposed to patients consulting for hearing evaluation in ENT department of University Hospital of Angers.