Inherited as an autosomal recessive trait, Pendred syndrome is a disease that 
shows congenital sensorineural hearing loss and goiter, with a positive finding 
in the perchlorate discharge test. Pendred syndrome results from various 
mutations in the PDS/SLC26A4 gene that cause production of an abnormal pendrin 
protein. More than 90 mutations in the PDS/SLC26A4 gene have been reported 
throughout the world. A recent study of 26 Korean patients with a relatively 
high frequency (65%) of a mutated PDS/SLC26A4 gene exhibited nonsyndromic 
deafness and an enlarged vestibular aqueduct. We report two patients with 
characteristics of typical Pendred syndrome, a 26-yr-old female and a 61-yr-old 
male, who were both homozygous for a previously reported missense mutation, 
H723R (Histidine 723Arginine) in the PDS/SLC26A4 gene.