OBJECTIVE: To analyze the clinical phenotype and genetic basis for a Chinese pedigree suspected for branchiootic syndrome (BOS). METHODS: The proband was subjected to target-capture high-throughput sequencing to detect potential variant of deafness-associated genes. Candidate variants were verified by Sanger sequencing of the family members. RESULTS: The proband was found to harbor a c.1627C>T (p.Gln543Ter) nonsense variant of the EYA1 gene. Sanger sequencing confirmed that all of the 4 patients with the BOS phenotype from the pedigree have harbored the same heterozygous variant. Based on the guidelines of the American College of Medical Genetics and Genomics, the variant was predicted to be pathogenic (PVS1+PS+PP3+PP4). CONCLUSION The c.1627C>T (p.Gln543Ter) variant of the EYA1 gene probably underlay the BOS phenotype in this pedigree. Above finding has provided a basis for its clinical diagnosis.
Branchio-Oto-Renal Syndrome ; China ; Humans ; Intracellular Signaling Peptides and Proteins/genetics* ; Mutation ; Nuclear Proteins/genetics* ; Pedigree ; Protein Tyrosine Phosphatases/genetics*

Objective: To analyze the clinical manifestations of a patient with branchiootic syndrome(BOS) and her families and to carry out genetic testing in order to specify the biological pathogenesis. Methods: Clinical data of the patient and her families were collected. Genomic DNA in the peripheral blood of the proband and her family members was extracted. All exons of 406 deafness-related susceptible genes as well as their flanking regions were sequenced by high-throughput sequencing, and the mutation sites of the proband and her parents were validated by Sanger sequencing. Results: There were nine members in three generations, of whom four presented with hearing loss, preauricular fistula and branchial fistula which met the diagnostic criteria of BOS. Proband and her mother presented with auricle malformation and inner ear malformation. And no one had abnormalities in the kidneys of all the patients. Pedigree analysis revealed that the mode of inheritance in the family was consistent with the autosomal dominant pattern. Mutational analysis showed that all the affected patients detected a heterozygous frameshift variation c.1255delT in the EYA1 gene, which had not been reported. Genotype and phenotype were co-isolated in this family. Such a frameshift variation produced a premature termination codon, thereby causing premature termination of translation (p.C419VFS*12). ACMG identified that the mutation was pathogenic. This mutation was novel and not detected in controls. A heterozygous missense variation mutation c.403G>A(p.G135S) in EYA1 gene was also detected in three members of this family. ACMG identified that the mutation clinical significance was uncertain. However, two of whom were normal, which seemed the disease was not caused by this mutation in this family. Conclusions: A novel frameshift mutation in EYA1(c.1255delT) is the main molecular etiology of BOS in the Chinese family. This study expands the mutational spectrum of EYA1 gene. The clinical manifestations are heterogeneous among patients in this family. The diagnosis of BOS should combine gene tests with clinical phenotypes analysis.
Branchio-Oto-Renal Syndrome/genetics* ; DNA Mutational Analysis ; Female ; Genetic Testing ; Humans ; Intracellular Signaling Peptides and Proteins/genetics* ; Mutation ; Nuclear Proteins ; Pedigree ; Protein Tyrosine Phosphatases/genetics*

Branchio-oto syndrome (BOS)/branchio-oto-renal syndrome (BORS) is a kind of autosomal dominant heterogeneous disorder. These diseases are mainly characterized by hearing impairment and abnormal phenotype of ears, accompanied by renal malformation and branchial cleft anomalies including cyst or fistula, with an incidence of 1/40 000 in human population. Otic anormalies are one of the most obvious clinical manifestations of BOS/BORS, including deformities of external, middle, inner ears and hearing loss with conductive, sensorineural or mix, ranging from mild to profound loss. Temporal bone imaging could assist in the diagnosis of middle ear and inner ear malformations for clinicians. Multiple methods including direct sequencing combined with next generation sequencing (NGS), multiplex ligation-dependent probe amplification (MLPA), or array-based comparative genomic hybridization (aCGH) can effectively screen and identify pathogenic genes and/or variation types of BOS/BORS. About 40% of patients with BOS/BORS carry aberrations of EYA1 gene which is the most important cause of BOS/BORS. A total of 240 kinds of pathogenic variations of EYA1 have been reported in different populations so far, including frameshift, nonsense, missense, aberrant splicing, deletion and complex rearrangements. Human Endogenous Retroviral sequences (HERVs) may play an important role in mediating EYA1 chromosomal fragment deletion mutations caused by non-allelic homologous recombination. EYA1 encodes a phosphatase-transactivator cooperated with transcription factors of SIX1, participates in cranial sensory neurogenesis and development of branchial arch-derived organs, then regulates the morphological and functional differentiation of the outer ear, middle ear and inner ear toward normal tissues. In addition, pathogenic mutations of SIX1 and SIX5 genes can also cause BOS/BORS. Variations of these genes mentioned above may cause disease by destroying the bindings between SIX1-EYA1, SIX5-EYA1 or SIX1-DNA. However, the role of SIX5 gene in the pathogenesis of BORS needs further verification.
Branchio-Oto-Renal Syndrome/pathology* ; Chromosome Deletion ; Comparative Genomic Hybridization ; Genetic Research ; Homeodomain Proteins/genetics* ; Humans ; Intracellular Signaling Peptides and Proteins ; Nuclear Proteins/metabolism* ; Pedigree ; Protein Tyrosine Phosphatases/metabolism*