Congenital deafness and goiter. Studies of a patient with a cochlear defect and inadequate formation of iodothyronines

A twenty-eight year old euthyroid Negro woman was studied for congenital deafness and goiter. The ability of her thyroid gland to accumulate radioiodine was normal. Dehalogenase activity was also normal, since monoiodotyrosine given orally was deiodinated at a normal rate. No abnormal iodoproteins were found in the thyroid gland, serum or urine. In contrast to previously described deaf patients with goiter, this subject was able to iodinate tyrosine. No thyroxine was found in a concentrated hydrolysate of thyroid tissue, although normal concentrations of thyroxine were present in serum. It is postulated that this patient has a partial defect in the condensation of iodotyrosines to form iodothyronines and that whatever thyroxine and triiodothyronine her gland did synthesize were rapidly released. Alternative hypotheses which cannot be excluded by the studies are considered. Seven other nondeaf goitrous subjects had reduced but measurable quantities of iodothyronines in their thyroid glands. Although the goitrous deaf subject had an intact vestibular apparatus, audiometric studies revealed total loss of hearing. Direct stimulation showed the absence of cochlear and eighth nerve action potentials. This suggests that the hearing loss is secondary to disease of the organ of Corti. Congenital deafness and goiter is a heritable disorder, but the precise relationship of one defect to the other is unknown.