Date of Completion

Spring 5-1-2018

Thesis Advisor(s)

R. Holly Fitch

Honors Major

Individualized Major


Behavioral Neurobiology | Biological Psychology | Cognitive Neuroscience | Cognitive Psychology | Communication Sciences and Disorders | Developmental Neuroscience | Developmental Psychology | Genetics | Health Psychology | Laboratory and Basic Science Research | Other Neuroscience and Neurobiology | Psychology | Public Health | Public Health Education and Promotion | Speech and Hearing Science


Usher syndrome type 2 is a complex autosomal recessive genetic disorder that is characterized by moderate to severe congenital sensorineural hearing loss, the onset of retinitis pigmentosa in the second decade of life, and in some cases, vestibular dysfunction. Mutations in the USH2A gene account for 85% of cases of type 2. The USH2A gene is responsible for encoding the protein usherin, which has an important role in the development and function of inner ear hair cells and retinal photoreceptors. Until recently, it has been believed that carriers of the USH2A mutation were phenotype free. However, recent data has suggested that carriers may exhibit certain deficits in sensorineural hearing.

Homozygous Ush2a knockout (KO) mice mimic the visual and hearing deficits seen in USH2A human patients. Little attention has been paid to the heterozygous preparation, but given recent evidence of subtle language deficits in these human carriers, we included heterozygous KO mice in the current study. Since ultrasonic mouse vocalizations (USV’s) are abundant in male mice when in the presence of a female, and can be used to assess defects in vocal communication, we measured and analyzed USV’s from homozygous and heterozygous Ush2a KO mice.

Overall, genotype had no significant effect on the results. This insignificance is something to take note of – the lack of findings may indicate that there are no vocal production deficits associated with the USH2A gene. Ultimately, this research is meant to help improve health outcomes in those diagnosed with Usher syndrome.