Novel partial duplication of EYA1 causes branchiootic syndrome in a large Brazilian family.

OBJECTIVE

To identify novel genetic causes of syndromic hearing loss in Brazil.

DESIGN

To map a candidate chromosomal region through linkage studies in an extensive Brazilian family and identify novel pathogenic variants using sequencing and array-CGH.

STUDY SAMPLE: Brazilian pedigree with individuals affected by BO syndrome characterized by deafness and malformations of outer, middle and inner ear, auricular and cervical fistulae, but no renal abnormalities.

RESULTS

Whole genome microarray-SNP scanning on samples of 11 affected individuals detected a multipoint Lod score of 2.6 in the EYA1 gene region (chromosome 8). Sequencing of EYA1 in affected patients did not reveal pathogenic mutations. However, oligonucleotide-array-CGH detected a duplication of 71.8Kb involving exons 4 to 10 of EYA1 (heterozygous state). Real-time-PCR confirmed the duplication in fourteen of fifteen affected individuals and absence in 13 unaffected individuals. The exception involved a consanguineous parentage and was assumed to involve a different genetic mechanism.

CONCLUSIONS

Our findings implicate this EYA1 partial duplication segregating with BO phenotype in a Brazilian pedigree and is the first description of a large duplication leading to the BOR/BO syndrome.