A novel splice site mutation in the EYA1 gene in a Korean family with branchio-oto (BO) syndrome

Branchio-oto-renal (BOR) and branchio-oto (BO) syndromes are autosomal dominant hereditary disorders characterized by the presence of hearing loss and branchial fistulae and cysts, with (BOR syndrome) or without (BO syndrome) renal malformations of varying degrees of severity. Mutations in the human homologous of the Drosophila eyes absent (EYA1) gene are frequently the cause of BOR/BO syndrome. Here we describe a Korean family with BO syndrome; the proband had preauricular pit, cup-shaped auricles, branchial fistula, and hearing loss, without renal involvement. Molecular genetic study revealed a novel mutation occurring in the consensus acceptor splice site of intron 8 (c.868-2A G) in the EYA1 gene. To the best of our knowledge, this is the first report of a splice site mutation in a family with BO syndrome without renal involvement, further extending the phenotypic-genotypic heterogeneity of BOR/BO syndrome.