A Novel mutation in the SLC26A4 gene in a Chinese family with Pendred syndrome

Abstract

Objective: To investigate the mutations in the SLC26A4 gene in a Chinese patient with Pendred syndrome.

Methods: The diagnosis of Pendred syndrome was confirmed by the family history, pure tone audiogram, perchlorate discharge test (PDT), and computed tomography (CT) of the temporal bone. DNA extraction, PCR and DNA sequencing were performed according to standard procedures. Mutations in the SLC26A4 gene were compared with 100 unrelated subjects to exclude common polymorphism. Splice-site mutation was further confirmed by restriction enzyme length polymorphism (RFLP) with the specifically designed primers.

Results: The proband presented with typical features of bilateral sensorineural deafness since childhood and goiter development in the early adulthood. Thyroid studies disclosed euthyroidism with elevated thyroglobulin, but negative for PDT. Marked enlargement of bilateral vestibular aqueduct (>1.5 mm) was found by CT of the temporal bone. A novel SLC26A4 splice-site mutation c.1263+1G>A (IVS10+1G>A) was identified in compound heterozygosity with the missense mutation c.1079C>T (p.A360V) in the proband. Both mutations were not found in the 100 unrelated Chinese.

Conclusions: Our results support previous findings that Pendred syndrome can be caused by compound heterozygous mutation in the SLC26A4 gene, in which IVS10+1G>A is a novel pathogenic mutation.

Keywords: Deafness; Enlarged vestibular aqueduct; Pendred syndrome; Pendrin; SLC26A4.