A Missense Variant in the Bardet-Biedl Syndrome 2 Gene (BBS2) Leads to a Novel Syndromic Retinal Degeneration in the Shetland Sheepdog.

Authors
Hitti-Malin, Rebekkah J 
Burmeister, Louise M  ORCID logo  https://orcid.org/0000-0002-6551-055X
Lingaas, Frode 

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Type
Article
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Abstract

Canine progressive retinal atrophy (PRA) describes a group of hereditary diseases characterized by photoreceptor cell death in the retina, leading to visual impairment. Despite the identification of multiple PRA-causing variants, extensive heterogeneity of PRA is observed across and within dog breeds, with many still genetically unsolved. This study sought to elucidate the causal variant for a distinct form of PRA in the Shetland sheepdog, using a whole-genome sequencing approach. Filtering variants from a single PRA-affected Shetland sheepdog genome compared to 176 genomes of other breeds identified a single nucleotide variant in exon 11 of the Bardet-Biedl syndrome-2 gene (BBS2) (c.1222G>C; p.Ala408Pro). Genotyping 1386 canids of 155 dog breeds, 15 cross breeds and 8 wolves indicated the c.1222G>C variant was only segregated within Shetland sheepdogs. Out of 505 Shetland sheepdogs, seven were homozygous for the variant. Clinical history and photographs for three homozygotes indicated the presence of a novel phenotype. In addition to PRA, additional clinical features in homozygous dogs support the discovery of a novel syndromic PRA in the breed. The development and utilization of a diagnostic DNA test aim to prevent the mutation from becoming more prevalent in the breed.

Publication Date
2021-11-08
Online Publication Date
2021-11-08
Acceptance Date
2021-11-04
Keywords
BBS, BBS2, PRA, canine, retinal degeneration, syndromic, Animals, Dog Diseases, Dogs, Female, Hybridization, Genetic, Male, Mutation, Missense, Phenotype, Proteins, Retinal Degeneration, Whole Genome Sequencing, Wolves
Journal Title
Genes (Basel)
Journal ISSN
2073-4425
2073-4425
Volume Title
12
Publisher
MDPI AG
Sponsorship
Wellcome Trust (090532/Z/09/Z)