Canine Sudden Acquired Retinal Degeneration Syndrome (SARDS) may be an Acquired Primary Ciliopathy, Phenotypically Similar to Human Alström and Bardet-Biedl Syndromes

Steven Toler^1*Kenneth Abrams²Dan Ward³

• ¹ClinPharmTox, LLC, Houston, United States
• ²Veterinary Ophthalmology Services, North Kingston, RI, United States
• ³Veterinary Medicine, University of Tennessee Medical Center, Knoxville, Tennessee, United States

Sudden Acquired Retinal Degeneration Syndrome (SARDS) is an acquired canine disease that presents as a rapidly progressive retinal degeneration, often accompanied by polyphagia, weight gain, polydipsia, polyuria and hyposmia. Alström (AS) and Bardet-Biedl (BBS) Syndromes are rare human autosomal recessive genetic disorders marked by progressive retinopathy, polyphagia, obesity, polydipsia, polyuria and hyposmia with varying degrees of phenotypic severity. While the etiology of AS and BBS are partially understood, the cause of acquired SARDS has remained elusive. Historically, scientific inquiry has focused on an immunologic insult and/or endocrinopathy as the cause of SARDS. Clinicians have often pointed to these Cushingoid symptoms noted above in SARDS patients as evidence of a contributing endocrinopathy However, systemic cortisol concentrations pre-and post-ACTH stimulation typically do not differ appreciably between normal patients and those with SARDS. Blindness due to photoreceptor degeneration, and the observed Cushingoid symptoms, may be readily produced by dysfunctional or absent primary cilia, as documented in human AS and BBS. Recognition of SARDS as a possible acquired ciliopathy may be the first step in seeking effective treatments.