Pendred Syndrome - Diagnosis

Diagnosis

Audiometry (measuring ability to hear sounds of a particular pitch) is usually abnormal, but the findings are not particularly specific and an audiogram is not sufficient to diagnose Pendred's syndrome. A thyroid goitre may be present in the first decade and is usual towards the end of the second decade. MRI scanning of the inner ear usually shows widened or large vestibular aqueducts with enlarged endolymphatic sacs and may show abnormalities of the cochleae known as Mondini dysplasia. Genetic testing to identify the Pendrin gene usually establishes the diagnosis. If the condition is suspected, a "perchlorate discharge test" is sometimes performed. This test is highly sensitive, but may also be abnormal in other thyroid conditions. If a goitre is present, thyroid function tests are performed to identify mild cases of thyroid dysfunction even if they are not yet causing symptoms.