Enlarged Vestibular Aqueducts from Autosomal Recessive Parents

Abstract

Objective: Enlargement of the vestibular aqueduct is a commonly detected inner ear abnormality and is inherited as an autosomal recessive trait caused by bi-allelic SLC26A4 mutations. Vertical transmission of EVA has rarely been reported in the literature. We report a case where EVA is inherited as a vertical transmission. Method: A bi-directional sequencing of SLC26A4 was performed to have a molecular genetic diagnosis of the 3 affected members of this family whose radiologic phenotype was documented by temporal bone CT. Results: The father and the mother as well as the proband were shown to have either EVA only or incomplete partition type II. The bi-directional sequencing of SLC26A4 demonstrated homozygous mutations of p.H723R and c.IVS7-2A>G from the father and the mother, respectively. The proband turned out to be a compound heterozygote of p.H723R and c.IVS7-2A>G. Conclusion: Given a wide variety of etiology for congenital deafness, it is interesting to find an assortative mating between EVA patients. We observed a vertical transmission of EVA and documented that SLC26A4 mutations segregating in the family with vertical transmission of EVA, which is usually inherited as a recessive manner.