Epidemiology of Non-syndromic Dominant Deafness

Study Overview
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Brief Summary
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Hearing impairment is a common disorder that affects at least 7% of individuals in our countries. Even the causes of hearing impairment are numerous, genetic causes represent the main factor of sensorineural deafness. Among hereditary non-syndromic deafness autosomal-dominant inheritance is observed in about 10-20% of the cases. These forms of deafness are usually post-lingual and progressive. To date more than 41 chromosomal localisation and 21 genes associated to non syndromic dominant deafness have been described. It represents an extreme genetic heterogeneity making difficult the studies of these forms of hearing impairment. But, genetic diagnostic testing is crucial in these cases. Indeed, therapeutic research are in the way to prevent the progression of the disorder. The aim of this work is to establish the prevalence of the different genes involved in these forms of deafness.

Detailed Description
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The protocol consists first in the recruitment of 150 families with non syndromic dominant hearing impairment. The families will be recruited by the clinical investigators. The clinic and radiological characteristics of the hearing impairment will be collected by the clinical investigators. Samples of patients and healthy relatives will be sent to the referral center. A linkage study of the whole genome by SNP studies is in progress in a cohort of large families affected by autosomal dominant deafness. This work will enable us to select the loci that may be frequently implicated in our population and screen these genes in the 150 families included in the protocol.

Official Title
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Genetic Epidemiology of Non-syndromic Dominant Deafness

Conditions
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Hearing Impairment

Intervention / Treatment
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* Biological: blood sample


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age > 4 years. Patient presenting familial dominant non syndromic hearing loss starting between 4 and 40 years old, over 2 generations Healthy volunteer from the same families Clinical and paraclinical assessment (genetic and ophthalmologic examination, audiometric tests, inner ear CT scan) Affiliated to the national health insurance benefit Signature of informed consent form Exclusion Criteria: hearing loss resulting from an extrinsic reason or an associated syndrome Defective or insufficient samples No or insufficient clinical and biological description No informed consent form

Ages Eligible for Study
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Minimum Age: 4 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 |
| --- | --- |
| 1<br>Patient presenting familial dominant non syndromic hearing loss starting between 4 and 40 years old, over 2 generations | Biological: blood sample<br>* Peripheral whole blood sample, 5 ml<br>|
| 2<br>Healthy volunteer from the same families | Biological: blood sample<br>* Peripheral whole blood sample, 5 ml<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The identification of a deleterious mutation of a gene coding a protein present in the cochlea |  | 1 day | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The phenotype genotype relationships after identification of the causative gene and mutation |  | 1 day | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Autosomal dominant inheritance, Mutation, Prevalence