Division of Genetics and Metabolism

Test module:Connexin-26 mutations

Estimated time to complete:6 min.
Number of questions: 6

Your name:

1. A main function of connexin-26 is to

transport small proteins into the cochlea
connect vesticular membrane to cochlear membrane
transport potassium into the endolymph
transport chloride ions into the perilymph

Note: You must check your answer after each selection.

2. Connexin-26 (GJB2) mutations account for what percentage of autosomal recessive hearing loss


3. Infants with hearing loss due to connexin-26 mutations also have an increased risk for

ear pits or tags
inner ear malformations
relatively small ears
enlarged vestibular aqueduct
none of the above

4. If a child has hearing loss due to a connexin-26 mutation then

both parents are likely to be carriers
the recurrence risk for future siblings is 50%
one parent is also likely to have hearing loss
neither parent is likely to have hearing loss

5. Connexin-26 (GJB2) mutations occur

predominantly in people of European origin
predominantly in people of European origin
only seen Ashkenazi-Jewish populations
mainly in those of Asian ancestry
with relatively high frequency in all populations

6. The degree of hearing loss in those with connexin-26 problems is usually


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