Pendred syndrome (PS) is an autosomal recessive disease that is characterized by 
congenital sensorineural hearing loss, goiter, and a partial iodine 
organification defect. In this study, we characterized the thyroid status and 
identified mutations in the SLC26A4 gene in Chinese subjects with PS. We 
evaluated 7 unrelated Chinese subjects who had PS. Biochemical analysis, formal 
audiogram, ultrasonography of the thyroid gland, perchlorate discharge test, 
computerized tomography scan of the vestibular aqueducts, and DNA sequence 
analysis of SLC26A4 were performed. Levels of thyroid hormones were essentially 
normal in all patients: 2 patients had goiters and/or elevated serum 
thyroglobulin levels, whereas 2 other patients had positive thyroid antibodies 
and a positive perchlorate discharge test. We identified SLC26A4 gene mutations 
in 6 of 7 probands and their affected relatives. The affected subjects in family 
I was compound heterozygous for 2 missense mutations: a mutation in exon 9 
(1079C>T) that resulted in the replacement of alanine by valine at codon 360 
(A360V) and a mutation in exon 19 (2168A>G) that resulted in the replacement of 
histidine by arginine at codon 723 (H723R). The affected subjects in families II 
and III all were homozygous for a mutation in intron 7. The probands IV and V 
were compound heterozygotes for the mutation in intron 7 and in exon 19, and the 
proband VI was compound heterozygous for the intron 7 mutation and a missense 
mutation in exon 12 (1343C>T) that resulted in the replacement of serine by 
leucine at codon 448 (S448L). One novel mutation was identified (A360V). We 
identified biallelic mutations in the SLC26A4 gene in 6 of 7 probands with PS in 
Taiwan, including a novel missense mutation. The mild thyroid dysfunction in 
these patients suggests that PS should be considered in all patients with 
congenital or early-onset hearing impairment.