Fluctuating sensorineural hearing loss associated with enlarged vestibular aqueduct maps to 7q31, the region containing the Pendred gene

The most common form of inner ear abnormality, enlarged vestibular aqueduct (EVA), is of particular interest because it is associated with characteristic clinical findings, including fluctuating and sometimes progressive sensorineural hearing loss and disequilibrium symptoms. Although EVA has been reported to be inherited in a recessive manner, nothing else is known about the genetic basis of this hearing loss. Here we report on the localization of the gene responsible for sensorineural hearing loss associated with EVA to chromosomal region 7q31, with maximum multipoint LOD score of 3.647. The EVA candidate gene region lies in a 1.7-cM interval between the flanking markers D7S501 and D7S2425. Interestingly, this region overlaps the region containing the gene responsible for Pendred syndrome, called PDS, which was identified recently. However, the present subjects did not fulfill the criteria for Pendred syndrome. It is hypothesized that different mutations within the PDS gene may cause different phenotypes ranging from EVA to the Mondini deformity seen in Pendred syndrome.