Other Names:PRA-PRCD, PRCDAffected Genes:PRCDInheritance:Autosomal RecessiveMutation:Point Mutation

Progressive retinal Atrophy, progressive Rod-cone degeneration (PRA-prcd) is a late onset, inherited eye disease affecting Golden Retrievers. PRA-prcd occurs as a result of degeneration of both rod and cone type Photoreceptor Cells of the Retina, which are important for vision in dim and bright light, respectively. Evidence of retinal disease in affected dogs can first be seen on an Electroretinogram around 1.5 years of age for most breeds, but most affected Golden Retrievers will not show signs of vision loss until 5 to 6 years of age or later. The rod type cells are affected first and affected dogs will initially have vision deficits in dim light (night blindness) and loss of peripheral vision. Over time affected dogs continue to lose night vision and begin to show visual deficits in bright light. Other signs of progressive retinal atrophy involve changes in reflectivity and appearance of a structure behind the retina called the Tapetum that can be observed on a veterinary eye exam. Although there is individual and breed variation in the age of onset and the rate of disease progression, the disease eventually progresses to complete blindness in most dogs. Other inherited disorders of the eye can appear similar to PRA-prcd. Genetic testing may help clarify if a dog is affected with PRA-prcd or another inherited condition of the eye.

The Mutation of the PRCD gene associated with progressive retinal Atrophy, progressive Rod-cone degeneration has been identified in Golden Retrievers, although its overall frequency in this breed is unknown.

Genetic testing of the PRCD gene in Golden Retrievers will reliably determine whether a dog is a genetic Carrier of PRA-prcd. PRA-prcd is inherited in an Autosomal Recessive manner in dogs meaning that they must receive two copies of the mutated gene (one from each parent) to develop the disease. In general, carrier dogs do not have features of the disease but when bred with another carrier of the same Mutation, there is a risk of having affected pups. Each pup that is born to this pairing has a 25% chance of inheriting the disease and a 50% chance of being a carrier of the PRCD gene mutation. Reliable genetic testing is important for determining breeding practices. Because symptoms do not appear until adulthood, genetic testing should be performed before breeding. In order to eliminate this mutation from breeding lines and to avoid the potential of producing affected pups, breeding of known carriers to each other is not recommended. Golden Retrievers that are not carriers of the mutation have no increased risk of having affected pups. However, because there are multiple types of PRA caused by mutations in other genes, a normal result in PRCD does not exclude PRA in a pedigree.

There may be other causes of this condition in dogs and a normal result does not exclude a different mutation in this gene or any other gene that may result in a similar genetic disease or trait.

• Dostal J, Hrdlicova A, Horak P. Progressive rod-cone degeneration (PRCD) in selected dog breeds and variability in its phenotypic expression. Veterinarni Medicina. 2011 Jun; 56(5):243-47. [Not In PubMed]
• Kohyama M1, Tada N, Mitsui H, Tomioka H, Tsutsui T, Yabuki A, Rahman MM, Kushida K, Mizukami K, Yamato O. Real-time PCR genotyping assay for canine progressive rod-cone degeneration and mutant allele frequency in Toy Poodles, Chihuahuas and Miniature Dachshunds in Japan. J Vet Med Sci. 2015 Nov 6. [PubMed: 26549343]
• Moody JA, Famula TR, Sampson RC, Murphy KE. Identification of microsatellite markers linked progressive retinal atrophy in American Eskimo Dogs. Am J Vet Res. 2005 Nov;66(11):1900-2. [PubMed: 16334947]
• Zangerl B, Goldstein O, Philp AR, Lindauer SJ, Pearce-Kelling SE, Mullins RF, Graphodatsky AS, Ripoll D, Felix JS, Stone EM, Acland GM, Aguirre GD. Identical mutation in a novel retinal gene causes progressive rod-cone degeneration in dogs and retinitis pigmentosa in humans. Genomics. 2006 Nov; 88(5):551-63. [PubMed: 16938425]

 Other Names:GR-PRA1, GR1-PRA Genes:SLC4A3Inheritance:Autosomal RecessiveMutation:Insertion

Progressive retinal Atrophy, golden retriever 1 (GR-PRA1) is a late-onset inherited eye disease affecting golden retrievers. Affected dogs begin showing clinical symptoms related to retinal degeneration between 6 to 7 years of age on average, though age of onset can vary. Initial clinical signs of progressive retinal atrophy involve changes in reflectivity and appearance of a structure behind the Retina called the Tapetum that can be observed on a veterinary eye exam. Progression of the disease leads to thinning of the retinal blood vessels, signifying decreased blood flow to the retina. Affected dogs initially have vision loss in dim light (night blindness) and loss of peripheral vision, eventually progressing to complete blindness in most affected dogs.

The Mutation of the SLC4A3 gene associated with progressive retinal Atrophy, golden retriever 1 has been identified in golden retrievers. Though the frequency in the overall golden retriever population is unknown, in one study of 369 golden retrievers clinically free of disease tested from the UK, US, Sweden, and France, 10.5% were carriers of the mutation.

Genetic testing of the SLC4A3 gene in golden retrievers will reliably determine whether a dog is a genetic Carrier of GR-PRA1. GR-PRA1 is inherited in an Autosomal Recessive manner in dogs meaning that they must receive two copies of the mutated gene (one from each parent) to develop the disease. In general, carrier dogs do not have features of the disease but when bred with another carrier of the same Mutation, there is a risk of having affected pups. Each pup that is born to this pairing has a 25% chance of inheriting the disease and a 50% chance of inheriting one copy and being a carrier of the SLC4A3 gene mutation. Reliable genetic testing is important for determining breeding practices. Because symptoms do not appear until adulthood, genetic testing should be performed before breeding. In order to eliminate this mutation from breeding lines and to avoid the potential of producing affected pups, breeding of known carriers to each other is not recommended. Golden retrievers that are not found to have this specific mutation have no increased risk of having affected pups for progressive retinal Atrophy, golden retriever 1. However, because there are multiple types of progressive retinal atrophy caused by mutations in other genes, a normal result in SLC4A3 does not exclude progressive retinal atrophy in a pedigree.

There may be other causes of this condition in dogs and a normal result does not exclude a different mutation in this gene or any other gene that may result in a similar genetic disease or trait.

• Downs LM, Wallin-Hakansson B, Boursnell M, Marklund S, Hedhammar A, Truve K, Hubinette L, Lindblad-Toh K, Bergstrom T, Mellersh CS. A frameshift mutation in golden retriever dogs with progressive retinal atrophy endorses SLC4A3 as a candidate gene for human retinal degenerations. PLoS One. 2011;6(6):e21452. [PubMed: 21738669]

 Other Names:GR-PRA2, GR2-PRA

Genes:TTC8Inheritance:Autosomal RecessiveMutation:Deletion

Progressive retinal Atrophy, golden retriever 2 (GR-PRA2) is a late-onset inherited eye disease affecting golden retrievers. Affected dogs begin showing clinical symptoms related to retinal degeneration at around 4 to 5 years of age on average, though age of onset can vary. Initial clinical signs of progressive retinal atrophy involve changes in reflectivity and appearance of a structure behind the Retina called the Tapetum that can be observed on a veterinary eye exam. Progression of the disease leads to thinning of the retinal blood vessels, signifying decreased blood flow to the retina. Affected dogs initially have vision loss in dim light (night blindness) and loss of peripheral vision, progressing to complete blindness in most affected dogs.

The Mutation of the TTC8 gene associated with GR-PRA2 has been identified in golden retrievers. Though the frequency in the overall golden retriever population is unknown, in one study of golden retrievers either free of clinical disease or of unknown PRA status tested from the UK, US, France, and Sweden, 3% were carriers of the mutation.

Genetic testing of the TTC8 gene in golden retrievers will reliably determine whether a dog is a genetic Carrierof GR-PRA2. GR-PRA2 is inherited in an Autosomal Recessive manner in dogs meaning that they must receive two copies of the mutated gene (one from each parent) to develop the disease. In general, carrier dogs do not have features of the disease but when bred with another carrier of the same Mutation, there is a risk of having affected pups. Each pup that is born to this pairing has a 25% chance of inheriting the disease and a 50% chance of inheriting one copy and being a carrier of the TTC8 gene mutation. Reliable genetic testing is important for determining breeding practices. Because symptoms do not appear until adulthood, genetic testing should be performed before breeding. In order to eliminate this mutation from breeding lines and to avoid the potential of producing affected pups, breeding of known carriers to each other is not recommended. Golden retrievers that are not found to have this specific mutation have no increased risk of having affected pups. However, because there are multiple types of progressive retinal Atrophycaused by mutations in other genes, a normal result in TTC8 does not exclude progressive retinal atrophy in a pedigree.

There may be other causes of this condition in dogs and a normal result does not exclude a different mutation in this gene or any other gene that may result in a similar genetic disease or trait.

• Downs LM, Hitti R, Pregnolato S, Mellersh CS. Genetic screening for PRA-associated mutations in multiple dog breeds shows that PRA is heterogeneous within and between breeds. Vet Ophthalmol. 2014 Mar;17(2):126-30. doi: 10.1111/vop.12122. Epub 2013 Nov 21. [PubMed: 24255994] 

 Affected Genes:PNPLA1Inheritance:Autosomal Recessive With Variable ExpressivityMutation:Complex Rearrangement

Common Symptoms

Ichthyosis (golden retriever type) is an inherited condition of the skin affecting golden retrievers. The age of onset and severity of disease are highly variable, however most affected dogs present before one year of age with flaky skin and dull hair. Over time the skin develops a grayish color and appears thick and scaly, especially over the abdomen. The symptoms may progress to severe scaling all over the body, may improve with age, or may come and go over the dog’s lifetime. While the prognosis is generally good for affected dogs, they are at increased risk for skin infections.

The Mutation of the PNPLA1 gene associated with Ichthyosis (golden retriever type) has been identified in the golden retriever. Though the exact frequency in the overall golden retriever population is unknown, approximately 44% out of 1600 golden retrievers tested from Australia, France, Switzerland, and the United States were carriers of the mutation and approximately 29% were affected.

Genetic testing of the PNPLA1 gene in golden retrievers will reliably determine whether a dog is a genetic Carrier of Ichthyosis (golden retriever type). Ichthyosis (golden retriever type) is inherited in an Autosomal Recessive manner in dogs meaning that they must receive two copies of the mutated gene (one from each parent) to develop the disease. In general, carrier dogs do not have features of the disease but when bred with another carrier of the same Mutation, there is a risk of having affected pups. Each pup that is born to this pairing has a 25% chance of inheriting the disease and a 50% chance of inheriting one copy and being a carrier of the PNPLA1 gene mutation. Reliable genetic testing is important for determining breeding practices. Because some affected dogs exhibit very mild symptoms, genetic testing should be performed before breeding. In order to eliminate this mutation from breeding lines and to avoid the potential of producing affected pups, breeding of known carriers to each other is not recommended. Golden retrievers that are not carriers of the mutation have no increased risk of having affected pups.

There may be other causes of this condition in dogs and a normal result does not exclude a different mutation in this gene or any other gene that may result in a similar genetic disease or trait.

• Grall A, Guaguère E, Planchais S, Grond S, Bourrat E, Hausser I, Hitte C, Le Gallo, M., Derbois C, Kim GJ, Lagoutte L, Degorce-Rubiales F, Radner FP, Thomas A, Küry S, Bensignor E, Fontaine J, Pin D, Zimmermann R, Zechner R, Lathrop M, Galibert F, André C, Fischer J. PNPLA1 mutations cause autosomal recessive congenital ichthyosis in golden retriever dogs and humans. Nat Genet. 2012 Jan 15;44(2):140-7. [PubMed: 22246504]
• Guaguere E, Bensignor E, Küry S, Degorce-Rubiales F, Muller A, Herbin L, Fontaine J, André C. Clinical, histopathological and genetic data of ichthyosis in the golden retriever: a prospective study. J Small Anim Pract. 2009 May;50(5):227-35. [PubMed: 19413748]
• Guaguere E, Thomas A, Grall, A, Bourrat E, Lagoutte L, Degorce-Rubiales F, Hitte C, Bensignor E, Fontaine J, Pin D, Queney G, Andre C. Autosomal recessive ichthyosis in golden retriever dogs: distribution and frequency of the PNPLA1 mutant allele in different populations. In Torres SMF, Fran LA, Hargis AM. Ames (eds), Advances in Veterinary Dermatology, 7th ed. John Wiley & Sons Ltd, 2013.

 Other Names:Canine degenerative myelopathy, DM Genes:SOD1Inheritance:Autosomal RecessiveWith Incomplete PenetranceMutation:Point Mutation

Degenerative Myelopathy caused by Mutation of the SOD1 gene is an inherited neurologic disorder of dogs. This mutation is found in many breeds of dog, including the golden retriever. While it is not clear for some of the other breeds, golden retrievers are known to develop degenerative myelopathy associated with this mutation. The variable presentation between breeds suggests that there are environmental or other genetic factors responsible for modifying disease expression. The average age of onset for dogs with degenerative myelopathy is approximately nine years of age. The disease affects the White Matter tissue of the spinal cord and is considered the canine equivalent to amyotrophic lateral sclerosis (Lou Gehrig’s disease) found in humans. Affected dogs usually present in adulthood with gradual muscle Atrophy and loss of coordination typically beginning in the hind limbs due to degeneration of the nerves. The condition is not typically painful for the dog, but will progress until the dog is no longer able to walk. The gait of dogs affected with degenerative myelopathy can be difficult to distinguish from the gait of dogs with hip dysplasia, arthritis of other joints of the hind limbs, or intervertebral disc disease. Late in the progression of disease, dogs may lose fecal and urinary continence and the forelimbs may be affected. Affected dogs may fully lose the ability to walk 6 months to 2 years after the onset of symptoms. Affected medium to large breed dogs, such as the golden retriever, can be difficult to manage and owners often elect euthanasia when their dog can no longer support weight in the hind limbs.

The Mutation of the SOD1 gene associated with degenerative myelopathy has been identified in the golden retriever. The overall frequency of this disease is unreported for golden retrievers. However, in one study of 334 golden retrievers tested, 0.6% were carriers of the mutation and 3% were at-risk/affected.

Genetic testing of the SOD1 gene in golden retrievers will reliably determine whether a dog is a genetic Carrierof degenerative myelopathy. Degenerative Myelopathy is inherited in an Autosomal Recessive manner in dogs meaning that they must receive two copies of the mutated gene (one from each parent) to develop the disease. In general, carrier dogs do not have features of the disease but when bred with another carrier of the same Mutation, there is a risk of having affected pups. Each pup that is born to this pairing has a 25% chance of inheriting the disease and a 50% chance of inheriting one copy and being a carrier of the SOD1 gene mutation. Reliable genetic testing is important for determining breeding practices. Because symptoms may not appear until adulthood and some at-risk/affected dogs do not develop the disease, genetic testing should be performed before breeding. Until the exact modifying environmental or genetic factor is determined, genetic testing remains the only reliable way to detect neurological disease associated with this mutation prior to death. In order to eliminate this mutation from breeding lines and to avoid the potential of producing affected pups, breeding of known carriers to each other is not recommended. Golden retrievers that are not carriers of the mutation have no increased risk of having affected pups.

There may be other causes of this condition in dogs and a normal result does not exclude a different mutation in this gene or any other gene that may result in a similar genetic disease or trait.

• Awano T, Johnson GS, Wade CM, Katz ML, Johnson GC, Taylor JF, Perloski M, Biagi T, Baranowska I, Long S, March PA, Olby NJ, Shelton GD, Khan S, O'Brien DP, Lindblad-Toh K, Coates JR. Genome-wide association analysis reveals a SOD1 mutation in canine degenerative myelopathy that resembles amyotrophic lateral sclerosis. Proc Natl Acad Sci U S A. 2009 Feb 24; 106(8):2794-9. [PubMed: 19188595]
• Coates JR, March PA, Oglesbee M, Ruaux CG, Olby NJ, Berghaus RD, O'Brien DP, Keating JH, Johnson GS, Williams DA. Clinical characterization of a familial degenerative myelopathy in Pembroke Welsh Corgi dogs. J Vet Intern Med. 2007 Nov-Dec; 21(6):1323-31. [PubMed: 18196743]
• Coates JR, Wininger FA. Canine degenerative myelopathy. Vet Clin North Am Small Anim Pract. 2010 Sep; 40(5):929-50. [PubMed: 20732599]
• Miller AD, Barber R, Porter BF, Peters RM, Kent M, Platt SR, Schatzberg SJ. Degenerative myelopathy in two Boxer dogs. Vet Pathol. 2009 Jul; 46(4):684-7. [PubMed: 19276068]
• Shaffer LG, Ramirez CJ, Sundin K, Carl C, Ballif BC (2015) Genetic screening and mutation identification in a rare canine breed, the Drentsche patrijshond. Vet Rec Case Rep. 3:e000185.
• Shaffer LG, Ramirez CJ, Sundin K, Connell LB, Ballif BC (2016) Genetic screening and mutation identification in a rare canine breed, the Cesky fousek. Vet Rec Case Rep. 4:e000346.
• Shelton GD, Johnson GC, O’Brien DP, Katz ML, Pesayco JP, Chang BJ, Mizisin AP, Coates JR. Degenerative myelopathy associated with a missense mutation in the superoxide dismutase 1 (SOD1) gene progresses to peripheral neuropathy in Pembroke Welsh Corgis and Boxers. J Neurol Sci. 2012 Jul 15;318(1-2):55-64. [PubMed: 22542607]
• Zeng R, Coates JR, Johnson GC, Hansen L, Awano T, Kolicheski A, Ivansson E, Perloski M, Lindblad-Toh K, O'Brien DP, Guo J, Katz ML, Johnson GS. Breed Distribution of SOD1 Alleles Previously Associated with Canine Degenerative Myelopathy. J Vet Intern Med. 2014 Feb 13. doi: 10.1111/jvim.12317. [PubMed: 24524809]

 Other Names:Duchenne-type muscular dystrophy, Dystrophin muscular dystrophy, DMD, GRMD Genes:DMDInheritance:X-Linked RecessiveMutation:Point Mutation

Golden Retriever muscular dystrophy is an inherited disease affecting Golden Retrievers. Affected dogs are unable to produce adequate amounts of a protein important for muscle contraction and relaxation. By 10 weeks of age affected puppies are noticeably smaller than littermates shortly after birth due to decreased growth associated with the inability to nurse. Affected dogs often need to be hand or bottle fed to prevent starvation. Beginning around 6 weeks of age, dogs begin to develop a progressively abnormal gait, muscle weakness, excessive drooling, muscle Atrophy of the head and trunk, abnormal extension or flexion of joints and a “roach backed” appearance in the lumbar spine that eventually progresses to a concave flexion. Affected dogs may also suffer from aspiration pneumonia and cardiac disease. The prognosis is related to disease severity with some dogs dying soon after birth due to disease complications and others surviving for years with only mild symptoms.

The Mutation of the DMD gene associated with Golden Retriever muscular dystrophy has been identified in Golden Retrievers, although its overall frequency in this breed is unknown.

Genetic testing of the DMD gene in Golden Retrievers will reliably determine whether a dog is a genetic Carrierof Golden Retriever muscular dystrophy. Golden Retriever muscular dystrophy is inherited in an X-Linked Recessivemanner in dogs meaning that female dogs with one copy of the Mutation are carriers and that affected female dogs must receive two copies of the mutated gene (one from each parent) to develop the disease while male dogs only require one copy of the mutated gene from the mother in order to develop disease. Therefore, male dogs more commonly present with symptoms of the disease. Each male pup that is born to a female dog known to be a carrier of Golden Retriever muscular dystrophy has a 50% chance of inheriting the disease. Female dogs that are not carriers of this mutation have no increased risk of having affected pups. Reliable genetic testing is important for determining breeding practices. In order to eliminate this mutation from breeding lines and to avoid the potential of producing affected pups, breeding of known carriers is not recommended. Golden Retrievers that are not carriers of the mutation have no increased risk of having affected pups.

There may be other causes of this condition in dogs and a normal result does not exclude a different mutation in this gene or any other gene that may result in a similar genetic disease or trait.

• Brinkmeyer-Langford C, Kornegay JN. Comparative genomics of X-linked muscular dystrophies: The Golden Retriever Model. Curr Genomics. 2013 Aug;14(5):330-42. doi: 10.2174/13892029113149990004. [PubMed: 24403852]
• Kornegay JN, Bogan JR, Bogan DJ, Childers MK, Li J, Nghiem P, Detwiler DA, Larsen CA, Grange RW, Bhavaraju-Sanka RK, Tou S, Keene BP, Howard JF, Jr., Wang J, Fan Z, Schatzberg SJ, Styner MA, Flanigan KM, Xiao X, Hoffman EP. Canine models of Duchenne muscular dystrophy and their use in therapeutic strategies. Mamm Genome. 2012 Feb;23(1-2):85-108. doi: 10.1007/s00335-011-9382-y. Epub 2012 Jan 5. Review. [PubMed: 22218699]
• Sharp NJ, Kornegay JN, Van Camp SD, Herbstreith MH, Secore SL, Kettle S, Hung WY, Constantinou CD, Dykstra MJ, Roses AD, Bartlett RJ. An error in dystrophin mRNA processing in golden retriever muscular dystrophy, an animal homologue of Duchenne muscular dystrophy. Genomics. 1992 May;13(1):115-21. [PubMed: 1577476]

 Other Names:Recessive dystrophic epidermolysis bullosa, DEB, EB, RDEBAffected Genes:COL7A1Inheritance:Autosomal RecessiveMutation:Point Mutation

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Dystrophic Epidermolysis Bullosa (DEB) is a hereditary skin disease affecting Golden Retrievers. Clinical signs of DEB are present at birth. Affected dogs have fragile skin that is easily damaged from rubbing or trauma resulting in blisters, ulcers and scarring of the skin. Areas that are most prone to blisters are the face, foot pads, genital areas and ears. In addition, affected dogs will develop blisters and ulcers inside the mouth and in the esophagus. Ulcerations of the skin and mucous membranes are painful and can become infected. Blistering of the skin tends to cease at around 8 months of age however, ulcers of the mouth and esophagus persist into adulthood. Dogs with DEB are often smaller than littermates, likely due to difficulties eating.

The Mutation of the COL7A1 gene associated with dystrophic epidermolysis bullosa has been identified in Golden Retrievers, although its overall frequency in this breed is unknown.

Genetic testing of the COL7A1 gene in Golden Retrievers will reliably determine whether a dog is a genetic Carrier of dystrophic epidermolysis bullosa. Dystrophic Epidermolysis Bullosa is inherited in an Autosomal Recessive manner in dogs meaning that they must receive two copies of the mutated gene (one from each parent) to develop the disease. In general, carrier dogs do not have features of the disease but when bred with another carrier of the same Mutation, there is a risk of having affected pups. Each pup that is born to this pairing has a 25% chance of inheriting the disease and a 50% chance of inheriting one copy and being a carrier of the COL7A1 gene mutation. Reliable genetic testing is important for determining breeding practices. In order to eliminate this mutation from breeding lines and to avoid the potential of producing affected pups, breeding of known carriers to each other is not recommended. Golden Retrievers that are not carriers of the mutation have no increased risk of having affected pups.

There may be other causes of this condition in dogs and a normal result does not exclude a different mutation in this gene or any other gene that may result in a similar genetic disease or trait.

• Baldeschi C, Gache Y, Rattenholl A, Bouillé P, Danos O, Ortonne JP, Bruckner-Tuderman L, Meneguzzi G. Genetic correction of canine dystrophic epidermolysis bullosa mediated by retroviral vectors. Hum Mol Genet. 2003 Aug 1; 12(15):1897-905. [PubMed: 12874109]
• Gache Y, Pin D, Gagnoux-Palacios L, Carozzo C, Meneguzzi G. Correction of dog dystrophic epidermolysis bullosa by transplantation of genetically modified epidermal autografts. J Invest Dermatol. 2011 Oct; 131(10):2069-78.[PubMed: 21697889]
• Palazzi X, Marchal T, Chabanne L, Spadafora A, Magnol JP, Meneguzzi G. Inherited dystrophic epidermolysis bullosa in inbred dogs: A spontaneous animal model for somatic gene therapy. J Invest Dermatol. 2000 Jul; 115(1):135-7. [PubMed: 10886525]

 Other Names:Brittle bone disease, OI

Genes:COL1A1Inheritance:Autosomal DominantMutation:Point Mutation

Osteogenesis imperfecta (OI) is an inherited Collagen disorder affecting dogs. Affected dogs typically present between 3 to 4 weeks of age with pain, lameness and fractures. OI is caused by a defect is in the way collagen is made. Because collagen is an important component of bone, bones of affected dogs are thinner than normal, fracture easily and do not heal properly. Other features of the disorder include loose joints and brittle teeth. Affected puppies may die shortly after birth and be smaller than littermates. Because of the severity of the disease, pups with OI are usually euthanized by 3 months of age.

The Mutation in the COL1A1 gene associated with osteogenesis imperfecta (golden retriever type) has been identified in a golden retriever, although its overall frequency in this breed is unknown.

Genetic testing of the COL1A2 gene will reliably determine whether a dog is a genetic Carrier of osteogenesis imperfecta (golden retriever type). Osteogenesis imperfecta (golden retriever type) is inherited in an Autosomal Dominant manner in dogs meaning that they only need to inherit one copy of the mutated gene to develop the disease. Each pup that is born to a parent carrying one copy of the Mutation has a 50% chance of inheriting one copy of the COL1A2 gene mutation and developing the disease. Reliable genetic testing is important for determining breeding practices. In order to eliminate this mutation from breeding lines and to avoid the potential of producing affected pups, breeding of known carriers is not recommended. Dogs that are not carriers of the mutation have no increased risk of having affected pups.

There may be other causes of this condition in dogs and a normal result does not exclude a different mutation in this gene or any other gene that may result in a similar genetic disease or trait.

• Campbell BG, Wootton JA, MacLeod JN, Minor RR. Sequence of normal canine COL1A1 cDNA and identification of a heterozygous alpha1(I) collagen Gly208Ala mutation in a severe case of canine osteogenesis imperfecta. Arch Biochem Biophys. 2000 Dec 1; 384(1):37-46. [PubMed: 11147834]

 Other Names:SAN Genes:tRNA-TyrInheritance:MitochondrialMutation:Deletion

Sensory Ataxic Neuropathy is an inherited neurologic condition affecting Golden Retrievers. Affected dogs typically present between 2 to 8 months of age with signs of neurologic disease. Symptoms include a lack of muscle coordination, abnormal gait and difficulty balancing especially affecting the hind limbs. Muscle mass appears normal and the condition does not appear to be painful. Although the disease progresses slowly, dogs are often humanely euthanized before three years of age.

The Mutation of the tRNA-Tyr gene associated with sensory ataxic neuropathy has been identified in Golden Retrievers, although its overall frequency in this breed is unknown.

Genetic testing of the tRNA-Tyr gene will reliably determine whether a dog is a genetic Carrier of sensory ataxic neuropathy. Sensory Ataxic Neuropathy is a mitochondrial disorder. Dogs only inherit mitochondrial DNA from the mother. Because this disease is inherited in a maternal inheritance pattern, both male and female dogs must inherit the mutated gene from the mother to develop the disease. Affected male dogs do not pass their mitochondrial DNA to their offspring and cannot produce affected pups. Each pup that is born to a female dog carrying a Mutation in the tRNA-Tyr gene is at risk of having the disease. However, the ratio of mitochondria without the mutation to the number of mitochondria with the mutation is important in determining whether a specific dog will actually develop features of the disease. Reliable genetic testing is important for determining breeding practices. Because disease presentation is variable, genetic testing should be performed before breeding. In order to eliminate this mutation from breeding lines and to avoid the potential of producing affected pups, breeding of carrier or affected female dogs is not recommended. Dogs that are not carriers of the mutation have no increased risk of having affected pups.

There may be other causes of this condition in dogs and a normal result does not exclude a different mutation in this gene or any other gene that may result in a similar genetic disease or trait.

• Baranowska I, Jäderlund KH, Nennesmo I, Holmqvist E, Heidrich N, Larsson NG, Andersson G, Wagner EG, Hedhammar A, Wibom R, Andersson L. Sensory ataxic neuropathy in golden retriever dogs is caused by a deletion in the mitochondrial tRNATyr gene. PLoS Genet. 2009 May; 5(5):e1000499. [PubMed: 19492087]
• Jäderlund KH, Orvind E, Johnsson E, Matiasek K, Hahn CN, Malm S, Hedhammar A. A neurologic syndrome in Golden Retrievers presenting as a sensory ataxic neuropathy. J Vet Intern Med. 2007 Nov-Dec; 21(6):1307-15.[PubMed: 18196741]

The neuronal ceroid lipofuscinoses are a group of inherited lysosomal storage disorders.  Lysosomes are structures in cells referred to as the stomach of the cell that breakdown waste products and other byproducts in the cell.  NCL affected dogs lack one of several enzymes necessary for the normal breakdown of certain types of fat or protein in the cells (called lipopigments.)  As this "debris" accumulates in neuronal cells (and to a lesser extent in other cells), the animal's mental and motor functions deteriorate.

Dogs with NCL start out as apparently normal and fully functional dogs.  Depending on which subtype of NCL they have, they will begin developing symptoms anywhere from 6 months to 4-6 years of age (for the adult onset varieties).  NCL is found in both humans and dogs as well as other species and share symptoms that include a progressive loss of mental and physical nervous system functions.    These exhibit as mental/intellectual decline and motor disturbance progressing to seizures, motor problems such as lack of muscle coordination, abnormal gait, difficulty balancing, visual disturbances progressing to blindness and behavioral changes including aggressiveness, dementia, aimless wandering behavior with episodes of confusion, depression and ultimately death.  The age of onset, rate of progression, age at death and the order in which symptoms appear depends on the particular disease.   This link illustrates some of the realities of an NCL affected dog.   

At least 7 forms have been identified thus far in dogs affecting six different genes.   Each is recessively inherited and testing is available for most of these. Various forms of NCL has been documented in the Dachshund, English setter,  Australian shepherd, American bulldog, Tibetan terrier, border collie, Polish owczarek nizinny (PON)/Polish lowland sheepdog, chihuahua and Labrador retriever with genetic testing for the causative gene mutation in the first six of these breeds. Dogs of other breeds have presented with NCL of unknown etiology.

You will hear many people in a breed say that "they have never heard of such a problem in the breed", or "that is only in the European dogs"/or "Australian dogs" or it is just in THOSE lines.  For instance, in border collies people will state that NCL "is primarily in the Australian lines" and yet dogs were apparently diagnosed with the issue in the US prior to the importation of "those lines", border collies in Japan also have the gene mutation and 42 documented carriers are listed on the border collie health database.  Dogs from each of the other breeds have, at a minimum, been clearly documented in research laboratories and veterinary universities  to have NCL and/or the gene mutation..  Even if people in the breed have "never heard of dogs with the problem" the problem is there.  Unfortunately, when an "unknown" genetic disease occurs that no one is familiar with, it often goes undiagnosed, unrecognized and unreported.  Recessive genes can be passed for many generations without affected individuals occurring until two carriers are actually bred to one another. The only way to know if a dog from an at risk breed carries this gene is to do molecular diagnostic testing.  Based on the severity of this group of diseases and the heartbreak involved in watching a once healthy dog slowly deteriorate, people may want to seriously consider testing regardless of not being aware of affected dogs "in the line".  As discussed in my recent Health Guarantee blog, disorders are not always readily recognized without "special testing" or without caregivers being specifically aware of what they are looking for.  

Chondrodysplasia (CDPA) is a general term used to describe a genetic skeletal trait affecting the development of cartilage growth plates. It is generally characterized by a normal sized trunk and shorter than normal limbs.

Chondrodystrophy (CDDY) refers to abnormal cartilage growth and bone development. Many dog breeds like Dachshunds, Bulldogs, Corgis, Pugs, French Bulldogs, Bassett Hounds, Pekineses, Lhasa Apsos, Shih Tzus, Beagles, etc. are defined as having shorter than normal limbs. Other skeletal characteristics that are sometimes associated with chondrodysplasia in dogs are: a lower jaw that may protrude further than normal, an unusually short upper jaw, or over under bite with crooked teeth. Bowed front legs, a crooked spine or breathing problems are also often found to be a problem. In 2009, a discovery found that dogs with CDPA have an autosomal dominant FGF4 insertion on chromosome 18. This promotes the short-legged phenotype. Fibroblast growth factor-4 (FGF4) is a common protein involved in early development on cartilage and bond length. This growth factor is directly correlated to limb development.

In 2017, researchers in the Bannasch Laboratory discovered a second FGF4 insertion on chromosome 12. This insertion is associated with CDDY in dogs with short limbs. It is also associated with the propensity to developmental Intervertebral Disc Disease (IVDD).   

Intervertebral Disc Disease (IVDD) is described as premature calcification of the nucleus pulposus. The nucleus pulposus is the inner core of the vertebral disc and is composed of water and a network of collagen fibers. The elastic structure works as a cushion to allow flexibility of the vertebral column. This enables the vertebral column to withstand forces of compression and torsion without damaging the disc. Premature calcification of the nucleus pulposus causes the disc to be less able to adjust to compressions and twists. The nucleus pulposus can then herniate through the protective layer of the annulus fibrosus. It then leaks out of the disc space and inflames the nerve roots next to the disc, causing severe pain and neurological dysfunction or myelopathy. IVDD is a degenerative disease and premature calcification can start in dogs that are less than a year old.

Animal Genetics offers testing for both CDDY and CDPA mutations. The current list of dogs with either CDDY and/or CDPA is not complete and will expand as more testing is completed. CDPA is considered a incomplete-dominant trait, meaning that dogs with 2 copies of the CDPA mutation are smaller than dogs with only 1 copy of the mutation. CDDY is a dominant trait, meaning that dogs only need a single copy to be affected and may be susceptible to IVDD. Dogs that test positive for both CDDY and CDPA have shorter legs. Research is ongoing to determine if dogs that test positive for CDDY and CDPA are more prone to IVDD than dogs that test positive for only CDDY. Testing can help identify dogs with a higher risk for developing IVDD by distinguishing short legged dogs with CDPA from those with CDDY.