[Branchio-oto-renal syndrome or branchio-oto syndrome: the clinical and genetic analysis in five Chinese families]

Objective: To screen the causative genes of five families with branchio-oto-renal syndrome (BORS) or branchio-oto syndrome(BOS) and to analyze the phenotypic characteristics and clinical management strategies of patients. Methods: Five families with BORS/BOR from December 2018 to September 2021 were recruited, information of patients, including family history and medical history, was collected, and genealogies were drawn. The examinations concerning audiology, nephrology, and radiology were performed on the affected individuals. Peripheral blood was obtained for DNA extraction, then next-generation sequencing technology was used to screen candidate variants associated with BORS/BOS. Based on patient's clinical results, the appropriate interventions were recommended and implemented. Results: Eight individuals were diagnosed with BOS or BORS. Of the eight patients, all had hearing loss, preauricular pits and ear malformations, and only four presented with branchial cleft fistulae or cysts. Except for two patients(5-I-2, 5-II-2) who did not undergo renal examination, the remaining six lacked renal abnormalities. Genetic analysis identified four likely pathogenic or pathogenic EYA1 variants (c.1715G>T, c.1140+1G>A, c.639G>C, c.1475+1G>C; NM_000503.6), and c.1715G>T was first reported in this study. Middle ear ossicular reconstruction was performed in 1-II-2,2-I-2 and 3-II-2, but did not yield the expected results; then hearing aids and cochlear implantation were recommended and achieved satisfactory results. Conclusions: Next-generation sequencing technology facilitates the diagnosis and genetic counseling of BORS/BOS. Hearing loss, preauricular pits, ear malformations and branchial cleft fistulae or cysts are the most common manifestations of patients in this study. Middle ear surgeries for improving hearing loss may have some limitations in BORS/BOS patients, and hearing aids and cochlear implantation can contribute to hearing gains.