- Thyroid hormone organification defect IIb
- This condition, clinically called Pendred syndrome, is the hereditary association of congenital deafness (deafness at the time of birth) and goiter (enlargement of the thyroid gland in the front of the neck) due to a defect in the making of thyroid hormone (thyroid hormone organification defect IIb). The features of Pendred syndrome in outline are as follows: Inner ear: Congenital neurosensory (nerve) deafness; defect in vestibular function; and malformation of the balance portion of the ear (cochlea); Hormonal: Seemingly normal level of thyroid hormones (euthyroid) due to compensated hypothyroidism; Neck: Goitrous swelling in front of neck; Intelligence: Mental retardation (due to congenital thyroid defect); Oncology : Possible increased risk of thyroid carcinoma (thyroid carcinoma); Laboratory : Evidence for defect in the making of thyroid hormone (thyroid hormone organification defect IIb); and Inheritance: Autosomal recessive with both seemingly normal parents carrying a copy of the Pendred syndrome (PDS) gene and each of their children having a 1 in 4 (25%) risk of inheriting both parental PDS genes and suffering from the syndrome. Pendred syndrome was clinically recognized and concisely described in 1896 by the English general practitioner Vaughan Pendred (1869-1946). Exactly a century later, the gene for Pendred syndrome was discovered (by Coyle and Sheffield and colleagues) to be on chromosome 7q. From the syndrome to the gene from 1896-1996! Pendred syndrome is also known as deafness with goiter and the goiter-deafness syndrome.
Medical dictionary. 2011.