Case report of a novel GREB1L gene mutation in a patient with branchio-oto-renal syndrome.

Branchio-oto-renal (BOR) syndrome is an uncommon disorder inherited in an autosomal dominant manner. Its main clinical manifestations include branchial cleft cysts, anterior auricular fistula, hearing impairment, and kidney malformations. BOR syndrome is associated with heterozygous pathogenic variants including EYA1, SIX1, and SIX5. The study focused on a 13-year-old Chinese boy who presented with hearing impairment, renal malformations, and bony atresia of the right external auditory canal with microtia. The boy's clinical manifestations met the diagnostic criteria for BOR syndrome. Two of the boy's family members underwent clinical examination. However, neither displayed a phenotype associated with BOR syndrome. The boy and his two relatives provided blood samples for genomic DNA extraction, followed by Sanger sequencing. A novel mutation in the GREB1L gene was identified in the boy, but neither of his family members exhibited the same variant. Identifying a novel mutation in GREB1L offers valuable insights into the genotype-phenotype correlation of BOR syndrome, improving the precision of early diagnosis and promoting the advancement of personalized treatment strategies.