UC Davis School of Veterinary Medicine Veterinary Genetics Laboratory

Labrador Retriever Genetic Tests

Tests Offered:
CNM | HNPK | HUU

Centronuclear Myopathy

Introduction

Centronuclear myopathy (CNM) is a naturally occurring, hereditary myopathy of Labrador Retrievers resulting from a mutation in the protein tyrosine phosphatase-like member A gene (PTPLA).  This condition is also known as: type II muscle fiber deficiency, autosomal recessive muscular dystrophy and hereditary myopathy. The disease is inherited in an autosomal recessive fashion with both sexes being equally affected.  CNM typically manifests in puppies at 2-5 months.  Signs of CNM include: generalized loss of muscle tone and control, exercise intolerance and an awkward gait. Dogs with one normal copy and one mutant copy of the gene do not display signs.  Breeding two carriers is predicted to produce 25% affected offspring and 50% carriers of the disease.

The VGL offers a DNA test for CNM to assist owners and breeders in identifying affected and carrier dogs. The test uses DNA collected from buccal (cheek) swabs, thus avoiding blood sample collection. Breeders can use results from the test as a tool for selection of mating pairs to avoid producing affected dogs.

ORDER TEST KITS | PRICE LIST
Allow 3-6 business days for results.

Results reported as:

N/N Normal - no copies of the CNM mutation
N/CNM Carrier - 1 copy of CNM mutation; dog is normal. Breedings between carriers are expected to produce 25% affected puppies.
CNM/CNM Affected - 2 copies of CNM mutation

This test is specific for the CNM mutation described in Labrador Retrievers.

Reference:

Pelé M, L. Tiret, JL Kessler, S Blot, JJ Panthier. 2005. SINE exonic insertion in the PTPLA gene leads to multiple splicing defects and segregates with the autosomal recessive centronuclear myopathy in dogs. Human Molecular Genetics 14(11):1417-1427.

Maurer M, J Mary, L Guillaud et al. 2012. Centronuclear myopathy in Labrador Retrievers: A recent founder mutation in the PTPLA gene has rapidly disseminated worldwide. Plos One 7(10): e46408.

Exercise-Induced Collapse

Introduction

Exercise-Induced Collapse (EIC) is a genetic neuromuscular disorder characterized by muscle weakness, lack of coordination and life-threatening collapse after intense exercise in otherwise apparent healthy dogs. Affected dogs tolerate mild to moderate activity but will display signs of EIC after 5-20 minutes of strenuous exercise. The severity of EIC varies, some affected dogs continue to run while dragging their hind legs while others have progression of weakness from rear to forelimbs resulting in a total inability to move. EIC events are often accompanied by a dramatic elevation of body temperature, although unaffected dogs also exhibit elevated temperatures under the same exercise conditions. EIC episodes last from 5-25 minutes with a gradual return to normal with no apparent residual weakness or stiffness. Affected dogs show signs of the disorder as early as 5 months of age, which is typically when more strenuous training and activity begins. Dogs with EIC can lead full, productive lives with proper management.  Owners of affected dogs should familiarize themselves with the types of activities that are appropriate for their dogs as well as specific triggers of EIC episodes.

EIC is caused by a mutation in dynamin 1 gene (DNM1 c.767G>T). It is inherited as an autosomal recessive disorder, which means that both males and females are affected equally, and that two copies of the mutation are needed to cause the disease. Dogs with one copy of the normal gene and one copy of the mutation (carriers) do not exhibit any signs of EIC.

The Veterinary Genetics Laboratory offers a genetic test for EIC. Test results assist veterinarians with diagnosis of EIC and help breeders identify carriers among breeding stock to avoid producing affected dogs. Matings between carriers are expected to produce 25% of affected puppies.

Testing recommendation:  Australian Cobberdog, Australian Labradoodle, Bouvier des Flandres, Boykin Spaniel, Cardigan Welsh Corgi, Chesapeake Bay Retriever, Cockapoo, Cocker Spaniel, Clumber Spaniels, Curly Coated Retriever, Deutsch-Drahthaar, English Cocker Spaniel, German Wirehaired Pointer, Labrador crosses, Labradoodle, Labrador Retriever, Old English Sheepdog, Pembroke Welsh Corgi, Vizsla

ORDER TEST KITS | PRICE LIST
Allow 5-10 business days for results.

Results reported as:

N/N

No copies of the EIC mutation.

N/EIC

1 - copy of the EIC mutation. Dog is a carrier. If bred to an N/N dog, 50% of offspring are predicted to be EIC carriers.

EIC/EIC

2 - copies of the EIC mutation. Dog is affected and, if induced, may exhibit exercise-induced collapse. If bred, dog will pass on a copy of EIC to all offspring.

References:

Patterson EE, Minor KM, Tchernatynskaia AV, Taylor SM, Shelton GD, Ekenstedt KJ, Mickelson JR. (2008). A canine DNM1 mutation is highly associated with the syndrome of exercise-induced collapse. Nat Genet. 40(10):1235-1239.

Minor KM, Patterson EE, Keating MK, Gross SD, Ekenstedt KJ, Taylor SM, Mickelson JR. (2011). Presence and impact of the exercise-induced collapse associated DNM1 mutation in Labrador retrievers and other breeds. Vet J. 189(2):214-219.

 

Hereditary Nasal Parakeratosis

Introduction

Hereditary Nasal Parakeratosis (HNPK) is a genetic defect caused by a mutation in a gene that regulates differentiation of nose skin cells. The mutation affects specialized cells of the nose resulting in the formation of a crust with cracks over the nasal area of young dogs. Affected dogs are otherwise healthy although leaked fluid tends to accumulate in the cracks.

HNPK is inherited in an autosomal recessive fashion with males and females being equally affected. Dogs with one normal and one affected gene (carriers) show no signs of the disease. Carrier dogs will pass on the affected gene to 50% of their offspring.
The VGL offers a test for HNPK. Genetic testing for the HNPK mutation is recommended for Labrador Retrievers. Labradoodles and other crosses with Labrador Retriever content may also be at risk. The test assists veterinarians with diagnosis of HNPK and helps breeders to identify carriers to avoid breeding these together. Mating of carriers is expected to produce 25% of affected puppies.

ORDER TEST KITS | PRICE LIST
Allow 3-6 business days for results.

Results reported as:

N/N Normal - no copies of the HNPK mutation
N/H Carrier - 1 copy of the HNPK mutation; dog is normal
H/H Affected - 2 copies of the HNPK mutation; dog will have nasal parakeratosis

Reference:

V. Jagannathan, J. Bannoehr, P. Plattet, R. Hauswirth, C. Drogemuller, M. Drogemuller, D. J. Wiener, M. Doherr, M. Owczarek-Lipska, A. Galichet, M. M. Welle, K. Tengvall, K. Bergvall, H. Lohi, S. Rufenacht, M. Linek, M. Paradis, E. J. Muller, P. Roosje, T. Leeb. 2013. A mutation in the SUV39H2 gene in Labrador Retrievers with Hereditary Nasal Parakeratosis (HNPK) provides insights into the epigenetics of keratinocyte differentiation. PLOS Genetics. Oct 9(10)
e1003848. https://doi.org/10.1371/journal.pgen.1003848.

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 3-6 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