Pendred's syndrome: a study of patients and relatives.

Four families, 29 members, with Pendred's syndrome were studied to clarify hearing loss and hormonal status. The ages ranged from 3 to 50 years. Complete Pendred's syndrome was found in 9 patients. They had bilateral profound hearing loss with residual hearing at low frequencies. Goiter was diagnosed at the age of 1 to 14 years with a positive perchlorate discharge test. Twelve of the patients' relatives showed partial Pendred's syndrome. Mild sensorineural hearing losses occurred in the low- and medium-range frequencies with normal perchlorate discharge test results in 6 cases. The other 6 had a slight drop in the perchlorate discharge test results with normal hearing. Five subjects were normal and 3 had normal hormonal and normal perchlorate discharge test results, but were not tested audiologically. This paper shows that patients with Pendred's syndrome may have goiter at birth or develop it between 8 and 14 years, that their deafness is bilateral and profound, and that their perchlorate discharge tests are positive. Relatives of Pendred's syndrome patients showed mild low-frequency sensorineural hearing loss without goiter and normal perchlorate discharge test results in half the cases, and a slight drop in the perchlorate discharge test results with normal hearing and without goiter in the other half. A correlation between these findings and genetic studies needs further investigation.