Hereditary Cataract Australian Shepherd Type – Genetics
Hereditary cataract Australian Shepherd type is a common genetic disease affecting eyes in the Australian Shepherds. It is one of the most common disoreds in purebred dogs, affecting approximately 100 breeds and representing a leading cause of blindness in dogs. Dominant form of the hereditary cataract Australian Shepherd type is caused by a single nucleotide deletion in the HSF4 gene, encoding for a heat shock transcription factor that regulates the expression of heat shock proteins in response to different stresses, such as oxidants, heavy metals, elevated temperatures and bacterial and viral infections.
HSF4 deletion is associated with bilateral, symmetrical cataract. Dogs carrying a single copy of mutated gene have an increased risk of developing a milder cataract, whereas homozygotes are more likely to develop more progressive, debilitating cataract. About 23% of Australian Shepherds are carriers of the mutated gene responsible for the disease.
Mellersh, C.S., Pettitt, L., Forman, O.P., Vaudin, M., and Barnett, K.C. (2006). Identification of mutations in HSF4 in dogs of three different breeds with hereditary cataracts. Veterinary Ophthalmology 9, 369–378.
Mellersh, C.S., McLaughlin, B., Ahonen, S., Pettitt, L., Lohi, H., and Barnett, K.C. (2009). Mutation in HSF4 is associated with hereditary cataract in the Australian Shepherd. Veterinary Ophthalmology 12, 372–378.