02959: Genetic Basis of non-HSF4 Hereditary Cataracts in a Family of Miniature American Shepherds

Abstract

Hereditary cataracts (HC) are one of the leading causes of blindness in dogs, observed in almost one hundred breeds. To date, only two genetic tests are available for HC, and they are only applicable to a small number of breeds. Both tests are in the same gene (called HSF4); one applies to Boston Terriers, French Bulldogs, and Staffordshire Bull Terriers and the other applies to Australian Shepherds. However, neither test explains all of the HC in these breeds. Miniature American Shepherds (MAS) are a breed developed out of the Australian Shepherds and investigators have recently collected DNA samples from a family of MAS containing multiple dogs affected with severe, rapidly progressive, adult-onset HC that were not explained by the available HSF4 Australian Shepherd test. The cataracts progressed so quickly that each affected dog required corrective surgery within months of diagnosis. Researchers will use this MAS family to search for new disease-associated genetic variants, via whole-genome sequencing. Once such a disease-associated mutation is identified, they will use additional MAS with known HC status to validate the mutation, and then establish the prevalence of that mutated allele in the breed at large. Investigators will also see if the mutated allele is present in Australian Shepherds. This study’s goal is to create a new genetic test for HC to help reduce the frequency of HC in the MAS and potentially other breeds.

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