Genetics

Genomics of hearing loss

Hereditary hearing loss is the most common sensory condition in children, and a genetic cause can be identified in nearly half of children with full or partial hearing loss.

Genetic testing is the cornerstone of care for these children, as it provides information on if and when the child may experience additional hearing loss as well as on associated conditions such as vision loss, heart disease and kidney disease. Yet despite major advances in hearing-related genetics, many patients with genetic forms of hearing loss lack diagnoses.

The Mayo Clinic Department of Otolaryngology — Head and Neck Surgery's Division of Genetics is using whole-exome and whole-genome approaches to discover genes that cause hearing loss. The discovery of such genes can lead to new therapies for hearing loss, potentially including gene therapies.

Zebrafish models of human hearing loss and gene discovery

Usher syndrome type 1 is a condition in which children are born deaf and then begin to lose their vision in early childhood; there is no known treatment. Division of Genetics faculty member Lisa A. Schimmenti, M.D., leads a research laboratory that uses the zebrafish, a small freshwater fish that shares 70% of its genome with humans, to study this syndrome.

In people, mutations in the gene MYO7A are the most common cause of Usher syndrome type 1. In zebrafish, mutations in the same gene cause deafness and vision impairment. Dr. Schimmenti's laboratory is studying medicines that could bypass the genetic defect in inner ear hair cells, potentially improving the response to sound.

Her lab also is using murine models of Usher syndrome type 1 to determine if the medicines identified in zebrafish might improve hearing in mice.