ICCFGG 2022
#52 Common variants in the CPT1A gene are associated with cataract in Northern breeds of domestic dog Sally L. Ricketts1 , Saija Ahonen2,3, Louise Pettitt1, Christopher A. Jenkins1, Maria Kaukonen2,3, Mike Boursnell4, Ellen Schofield1, Hannes Lohi2,3*, Cathryn S. Mellersh1* *Contributed equally sr958@cam.ac.uk 1Kennel Club Genetics Centre, Department of Veterinary Medicine, University of Cambridge, UK, 2University of Helsinki, Helsinki, Finland, 3The Folkh√§lsan Institute of Genetics, Helsinki, Finland, 4Kennel Club Genetics Centre: Formerly at the Animal Health Trust, Newmarket, Suffolk, UK Primary hereditary cataract affects a significant number of purebred domestic dog breeds and is a major cause of blindness in dogs. Cataracts are common in Northern breeds such as the Siberian Husky, Alaskan Malamute and Samoyed, but their aetiology is currently unknown. To date there are only two genetic loci known to be causally related to primary hereditary cataract in the dog. To search for genetic loci associated with cataracts in Northern breeds, we used a genome-wide association study approach in three breeds—Siberian Husky, Alaskan Malamute and Samoyed. Cases were defined as dogs with bilateral posterior polar subcapsular cataracts and controls were at least four years of age with no evidence of cataracts or other ocular abnormality. We found a genome-wide statistical association for cataracts in the Siberian Husky on canine chromosome 18 (CanFam 3.1; P-value: 1.1x10-7). The Samoyed breed also showed evidence for association in the same genomic region (P-value: 2.4x10-5). We subsequently used targeted resequencing of the ~6.5 Mb associated region in ten Siberian Huskies and whole genome sequencing of Siberian Husky, Alaskan Malamute, Samoyed and Norwegian Buhund cases to screen for candidate causal variants. These analyses identified common SNPs in the carnitine palmitoyltransferase 1A (CPT1A) gene that are associated with bilateral posterior polar subcapsular cataracts in the Siberian Husky, Samoyed, Icelandic Sheepdog and Norwegian Buhund and we demonstrate that CPT1A is expressed in the dog lens, and retina through RNAseq. Our findings represent a novel locus for cataracts in dogs. However, further work is needed to elucidate the pathophysiology underlying the association between CPT1A and cataracts in Northern breeds. #53 SOAT1 missense variant in two kittens with sebaceous gland dysplasia Sarah Kiener1,2 , Barbara McMahill3, Verena K. Affolter4, Vidhya Jagannathan1,2, Tosso Leeb1,2 sarah.kiener@vetsuisse.unibe.ch 1Institute of Genetics, Vetsuisse Faculty, University of Bern, Bern, Switzerland, 2Dermfocus, University of Bern, Bern, Switzerland, 3IDEXX Reference Laboratories, Inc., WY, USA, 4Department of Pathology, Microbiology, Immunology, School of Veterinary Medicine, University California Davis, CA, USA Two 4-months old sibling domestic short haired kittens were presented with dry dark brown to black debris around the eyes, nose, and ears, dark crusting on the legs and a thin poor hair coat. Skin biopsies of both kittens revealed abnormalities of sebaceous glands, characterized by small to prominent glands with lack of normal sebocyte arrangement and differentiation and atypical cytologic features. Alternatively, sebaceous glands were absent. Hair follicles had a distorted silhouette, interpreted as a change secondary to sebaceous gland dysplasia. The clinical and his- topathological findings and the early age of onset were suggestive of a congenital skin disorder,
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