Natural History in Children Up to 16 Years with Mild to Profound Hearing Loss Due to Mutations in GJB2 / OTOF Genes

Main Inclusion Criteria:

Participants meeting all the following main inclusion criteria will be eligible to participate in the study:

• Aged ≤ 16 years on the date of signed informed consent for cohort 1 and ≤ 10 yearsfor cohort 2;

• With a diagnosis of non-syndromic, bilateral, mild to profound, sensorineuralhearing loss (according to the American Speech Language-Hearing Association);

• With documented genotyping results showing mutation(s) in GJB2 or OTOF genes;

• Written informed consent as required by local regulations.

• Either without Cochlear Implant, or with unilateral or bilateral Cochlear Implant(s)

Exclusion Criteria:

Participants presenting with any of the following main exclusion criteria will not be included in the study

• Other type of deafness, such as unilateral deafness, persistent conductive deafness,malformation syndrome, syndromic deafness, known familial deafness linked tomutations in other genes than OTOF or GJB2;

• Documented genotyping results showing pathogenic mutation(s) in other gene(s) thanGJB2 or OTOF genes in the tested panel;

• Unable and/or unwilling to comply with all the protocol requirements and/or studyprocedures.