UC Davis School of Veterinary Medicine Veterinary Genetics Laboratory

American Staffordshire, American Pit Bull Terrier Genetic Tests

Cone Rod Dystrophy 1 and 2

Introduction

Early onset retinal degeneration in the American Staffordshire Terrier (cone rod dystrophy 1, crd1) and American Pit Bull Terrier (cone rod dystrophy 2, crd2) result from mutations in PDE6B and IQCB1 respectively. Visual impairment can be observed at less than one year of age with severe blindness by early adulthood. Both mutations have an autosomal recessive mode of inheritance and thus males and females are equally affected. Carriers (with one copy of defective gene) have no apparent visual impairment and can only be detected through genetic testing. Within each breed, crossing of carriers is predicted to produce 25% affected offspring. Because the mutations are in different genes and thus independent from each other, a dog with one copy of each mutation will not be affected and crossing carriers of crd1 with carriers of crd2 will not produce affected offspring.

Genetic testing for crd1 and crd2 is recommended for the American Staffordshire and American Pit Bull Terriers and dogs derived from these breeds.

ORDER TEST KITS | PRICE LIST
Allow 2-6 business days for results.

Results reported as:

N/N Normal - no copies of the crd1 mutation
N/CRD1 Carrier - 1 copy of the crd1 mutation; dog is normal
CRD1/CRD1 Affected - 2 copies of the crd1 mutation; dog will go blind

 

N/N Normal - no copies of the crd2 mutation
N/CRD2 Carrier - 1 copy of the crd2 mutation; dog is normal
CRD2/CRD2 Affected - 2 copies of the crd2 mutation; dog will go blind

Reference:

Goldstein O, Mezey JG, Schweitzer PA, Boyko AR, Gao C, Bustamante CD, Jordan JA, Aguirre GD, Acland GM. 2013.  IQCB1 and PDE6B mutations cause similar early onset retinal degenerations in two closely related terrier dog breeds. Invest Ophthalmol Vis Sci. Oct 25;54(10):7005-19.

Canine Hyperuricosuria
Introduction

Hyperuricosuria (HUU)means elevated levels of uric acid in the urine. This trait predisposes dogs to form stones in their bladders or sometimes kidneys. These stones often must be removed surgically and can be difficult to treat. Hyperuricosuria is inherited as a simple autosomal recessive trait. The trait can occur in any breed but is most commonly found in the Dalmatian, Bulldog and Black Russian Terrier.  Dalmatians are considered to be homozygous for hyperuricosuria. A mutation in exon 5 of the gene Solute carrier family 2, member 9 (SLC2A9) has been found to be associated with hyperuricosuria in dogs.  A DNA test for this specific mutation can determine if dogs are normal or if they carry one or two copies of the mutation. Dogs that carry two copies of the mutation will be affected and susceptible to develop bladder/kidney stones.

ORDER TEST KITS | PRICE LIST
Allow 2-6 business days for results.

Detailed Hyperuricosuria Information

The VGL offers a DNA test for hyperuricosuria to assist owners and breeders in identifying affected and carrier dogs. The test uses DNA collected from buccal swabs thus avoiding invasive blood collection. Breeders can use results from the test as a tool for selection of mating pairs to avoid producing affected dogs. The test is offered to all breeds, including American Pitbull Terrier, American Staffordshire Terrier, Australian Shepherd, Black Russian Terrier, Bulldog, Dalmatian, German Shepherd, Giant Schnauzer, Jack Russel/Parsons Terrier, Labrador Retriever, Large Munsterlander, South African Boerboel, Vizsla and Weimaraner.

The following chart details the expected outcomes of matings for all possible combinations of hyperuricosuria genotypes.

Female

Male

N/N

N/HU

HU/HU

N/N

100% N/N

50% N/N, 50% N/HU

100% N/HU

N/HU

50% N/N, 50% N/HU

25% N/N, 50% N/HU, 25% HU/HU

50% N/HU, 50% HU/HU

HU/HU

100% N/HU

50% N/HU, 50% HU/HU

100% HU/HU

Results reported as:

N/N: no copies of hyperuricosuria mutation; dog is normal
N/HU: 1 copy of hyperurisosuria mutation; dog is normal but is a carrier
HU/HU: 2 copies of hyperuricosuria mutation; dog is affected and susceptible to develop bladder/kidney stones.

Research Hyperuricosuria is ongoing to determine other breeds with this problem.  We recommend testing any dog that has formed kidney or bladder stones composed of urate or uric acid. If the dog has the mutation then treatment modalities for Dalmatians can be used to treat the dog.

References:

Bannasch D, N Safra, A Young, N Karmi, RS Schaible and GV Ling (2008) Mutations in the SLC2A9 Gene Cause Hyperuricosuria and Hyperuricemia in the Dog. PLoS Genetics 4(11): e1000246. doi:10.1371/journal.pgen.1000246

Karmi N, EA Brown, SS Hughes, B McLaughlin, CS Mellersh, V Biourge, and DL Bannasch (2010) Estimated Frequency of the Canine Hyperuricosuria Mutation in Different Dog Breeds. Journal of Veterinary and Internal Medicine 2010;24:1337–1342.

 

 
Veterinary Genetics Laboratory, Tel 530-752-2211, Email VGL