Pendred syndrome is an autosomal recessive disorder characterized by congenital 
deafness and goiter. The gene responsible for this syndrome is located on 
chromosome 7q31. The disorder is related to a defect in iodine organification, 
but the molecular basis of the defect remains unknown. We report two cases of 
Pendred syndrome, a young woman and her brother. The patients presented 
deafness, goiter that appeared in the prepubertal years, and a positive 
perchloriate discharge test. The genetic factors, clinical features, and 
diagnosis are reviewed.