Osteochondrodysplasia

Gene: SLC13A1

Transmission: Autosomal recessive

For an autosomal recessive genetic disease an animal must have two copies of the mutation in question to be at risk of developing the disease.  Both parents of an affected animal must be carriers of at least one copy of the mutation.  Animals that have only one copy of the mutation are not at risk of developing the disease but are carrier animals that can pass the mutation on to future generations.

Mutation: Deletion, SLC13A1 gene; c.99+3353 del 56671 nt, chr.14.

Medical system: Skeletal

Breeds: American Staffordshire Terrier/Amstaff, Bichon Frise, Cavalier King Charles Spaniel, Chihuahua, Papillon / Continental Toy Spaniel, Pomeranian, Poodle - Miniature (Dwarf), Poodle - Toy, Schnauzer - Miniature

Age of onset of symptoms: 3 weeks.

Osteochondrodysplasia (OCD) in the miniature poodle is a genetic disease of endochondral ossification first described in European lines more than 50 years ago.  As its name implies, OCD involves a growth problem of both cartilage and bone formation.  Clinical observations include abducted hind limbs, enlarged joints, shortened and bowed long bones, an undershot jaw and misshapen paws.  Joint stiffness and arthritis are a feature.  Radiographic anomalies within the epiphesial plates of long bones are apparent.  Clinical lab work shows a hyposulfatemia and a hypersulfaturia.  Molecular characterization of affected animals revealed a large deletion on chromosome 14 that ablates the SLC13A1 gene.  The SLC13A1 gene codes for a protein found within intestinal epithelium cells where it controls dietary absorption of sulfates, and within renal epithelium cells where it is involved in resorption of sulfates from the urine.  Sulfates are important for extracellular matrix components such as the proteoglycan chondroitin sulfate, which is important for normal cartilage and bone formation.  In 2012, carrier frequencies for the mutation in the miniature poodle in the United States were reported to be 9.7%.  A more recent commercial survey detected the presence of the mutation in several additional dog breeds.  The availability of a DNA test to detect asymptomatic carrier animals now enables breeders to make informed breeding decisions to both eliminate the disease and eventually the mutation from their animals.

References:

OMIA link: [1400-9615]

Donner J, Freyer J, Davison S, et al. (2023) Genetic prevalence and clinical relevance of canine Mendelian disease variants in over one million dogs.  PLoS Genet. 19(2):e1010651. [pubmed/36848397]

Neff MW, Beck JS, Koeman JM, et al. (2012) Partial deletion of the sulfate transporter SLC13A1 is associated with an osteochondrodysplasia in the Miniature Poodle breed. PLoS One 7:e51917.  [pubmed/23300579]

Riser WH, Haskins, ME, Jezyk PF, et al. (1980) Pseudoachondroplastic dysplasia in miniature poodles: clinical, radiologic, and pathologic features. J Am Vet Med Assoc 176:335-41.  [pm/6987200]

Contributed by:  Jade Fournier and Maria Paula Reina Velasquez, Class of 2028, Faculty of Veterinary Medicine, University of Montreal.  (Translation, DWS)