Prenatal diagnosis and genetic analysis of a fetus with Branchio-oto-renal syndrome: A case report

Branchio-oto-renal (BOR) syndrome is an autosomal-dominant disorder characterized by branchial arch anomalies, hearing loss, and kidney defects. Mutations in the human EYA1 gene have been reported associated with BOR syndrome. Here we identified that a novel variant, EYA1: NM_000503.4: c.827-1G > C (Intron 8, shear mutation) was associated with BOR in a fetus of a Chinese family.Prenatal ultrasound examination showed that both kidneys of the fetus were small and the echo of both kidneys was enhanced. The amount of amniotic fluid was normal, and no other structural abnormalities of the fetus were found. Fetal umbilical cord blood puncture was performed. No abnormality was found in karyotyping and chromosomal microarray analysis (CMA) results. Thus, we performed a trio-based whole exome sequencing (WES), and found that the fetus carried a novel homozygous variant, EYA1: NM_000503.4: c.827-1G > C (Intron 8, shear mutation), but the parents do not have this mutation. The variation sites of fetus and parents were verified by Sanger sequencing to clarify the source of pathogenic variation.Combined with fetal imaging examination, the novel variation of EYA1: NM_000503.4: c.827-1G > C is the cause of fetal renal dysplasia. This case report indicates that the early use of appropriate technology can clarify the etiology of fetal disease and guide prognosis consultation.