Integrative treatment for inherited diseases in dogs
Because inherited diseases are chronic conditions, integrative medicine has many contributions to make that can help support the canine patient’s health.
Nancy Scanlan, DVM, MS, CVA
An “inherited disease” is officially defined as a condition that has been proven to be inherited, or to be statistically higher in one or more specific breeds than in others.1 Inherited diseases range from mild to life-threatening. Integrative medicine has quite a bit to offer in the treatment and management of these conditions.
Inherited diseases explained
Over 300 canine diseases are officially proven to be inherited.2 This number is probably low, especially when compared to humans and mice. In humans, over 2,000 genetic diseases have been identified; there are over 1,300 mouse models for human diseases (which means over 1,300 mutations).3
The study of affected animals in pedigrees is the first step to show inheritance of a particular disease. This is followed in a number of cases by identifying the specific genes involved and, ideally, developing a test for those genes. Another method is to review prevalence of a disease in a specific breed and to compare it to the prevalence of the disease in the rest of the canine population, but this is less scientifically predictive.4
- A disease caused by the single mutation of a dominant gene is easiest to spot. Any animal with a single copy of that gene will have that disease. Genes that are dominant but with incomplete penetrance may have variable expression, so symptoms of the disease can be anywhere from mild to severe, depending on the degree of gene expression. Type 1 Von Willebrand disease (vWD) in Dobermans is such a disease. Because the variability means many afflicted Dobermans may not show severe signs of excessive bleeding, it has been difficult to get breeders to remove affected animals from the gene pool. In such cases, this type of problem can become widespread throughout a breed.5
- On the other hand, diseases may be caused by a single recessive mutation, which means that until a test is developed to determine carriers, and until a breed association becomes resolved to eradicate that trait from the breed, the trait may become widespread. This is especially true when a popular sire is also a carrier for the disease. Type 3 vWD in Scottish terriers is a classic example as it has autosomal recessive inheritance whereby two obligate carrier heterozygotes can produce clinically affected homozygous offspring that express a severe bleeding tendency. The affected gene has been identified and extensive carrier testing has virtually eliminated most of this problem from the breed.4 All but one type of progressive retinal atrophy (PRA) is another autosomal recessive example. To further complicate matters, this disease can be caused by at least six different mutations.6-11 There are six different DNA tests available. Fortunately, most breeds affected by PRA have the same type: PRCD (Progressive Cone/Rod Degeneration).4 Conscientious breeders involved with breeds afflicted with this problem are actively testing and removing carriers from the breeding pool.
- The hardest diseases to control with conventional medicine are those with multiple genes involved; other factors include conformation, nutrition, breed, rate of growth, amount of exercise and others. Hip dysplasia is an example. This type of problem is one where intervention with integrative veterinary medicine can help the most, especially when it’s started at an early age.
Purebred dogs are more likely to have certain specific inherited diseases than dogs whose ancestors come from two or more breeds. But this does not mean all non-purebred dogs are healthier. They may inherit problems from all their ancestors. In addition, certain body shapes (as in the case of brachycephalic dogs) are associated with specific disease syndromes, regardless of whether a dog is purebred or crossbred. A survey at UC Davis involving dogs affected with 24 of the most common genetic diseases with major health consequences showed that for about half of them, there was no difference in occurrence between purebred versus mixed breed dogs.12,13
Popular breeds are more likely to have a longer list of inherited diseases than less popular breeds. There are a larger number of dogs among the popular breeds, so there will be more individuals with some of the less common forms of the disease, allowing more opportunities for the disease to continue within that breed. In addition, owners of popular breeds may be more likely to breed their dogs with the nearest dogs of the same breed without any genetic screening, increasing the chances of spreading undetected problems.14
One should not rely solely on official surveys of the incidence of inherited diseases. A breed that’s new to a country may not have been present long enough for any problems to become obvious. A rare breed may not have enough members to enable a good statistical sampling, or to show signs of the problem so it can be recognized as being breed-related.2 Pet owners may purchase a dog based on an internet search for “healthiest dog breed” and end up with a rare breed that has a number of unexpected problems.
The role of integrative medicine
Because these are inherited genetic defects, often associated with anatomical changes, integrative medicine is not going to prevent most of them, unlike diseases associated with the environment or nutrition. However, because the cause (genetic) is present over an animal’s entire lifespan, inherited diseases are chronic conditions. For chronic diseases and those with multiple causes, integrative medicine has many contributions to offer that can help support the patient’s health.
Chronic conditions often respond better to integrative medicine than to conventional medicine alone. For some genetic diseases, such as vitamin A-responsive dermatosis and zinc-responsive dermatosis, the conventionally recognized treatment is already essentially an integrative one involving a single nutraceutical (a vitamin or mineral used in a higher dose than is present in conventional pet food and supplements).
Obviously, some dysfunctions and diseases are associated with body structure. Dogs with pendulous ears are much more likely to have chronic otitis than dogs with erect ears. Chondrodysplastic breeds with short legs are more likely to have Type I intervertebral disc disease (IVDD) than breeds with a more wolf-like conformation. In the case of pendulous ears, integrative treatment will not change the shape of the ears but neither will conventional treatment. But often, an integrative treatment can be used to prevent the otitis associated with pendulous ears, with longer-lasting results than conventional treatment. In the case of IVDD, prevention is harder to accomplish, but treatments such as acupuncture can have analgesic effects equal to or even surpassing those of conventional medicine. The same is true of most polygenic conditions that can cause pain, such as hip dysplasia.
When the problem is related to conformation or body structure, the pet owner’s idea of “cure” may not be realistic. Dangling dewclaws on the hind legs, with nails that grow and curve around into the tissue, are not going to fall off or allow the nails to wear down normally, no matter what treatment is used. This is where an “integrative” approach applies: the ideal treatment is either regularly trimming the nails or removing any excess toes.
In contrast, other diseases with multiple contributing factors, such as hip dysplasia, can be improved or even in some cases cured, if proper nutrition and other treatment are started early enough. Inherited skin diseases in general are especially amenable to integrative treatments, including almost half of those identified as being inherited. Some immune disorders also can respond dramatically to integrative treatments. In such cases, a spectrum of treatments is most effective, often involving a combination of nutrition, nutraceuticals, herbal therapy, and/or homeopathy as well as other modalities. In short, integrative medicine can help alleviate the issues caused by or associated with many inherited diseases in dogs.
Online lists of inherited diseases in dogs
Dodds, WJ. 2011. Guide to Congenital and Heritable Disorders in Dogs (Includes Genetic Predisposition to Diseases). Humane Society Veterinary Medical Association, 2011. Available as a download at hsvma.org/assets/pdfs/guide-to-congenital-and-heritable-disorders.pdf
vet.cam.ac.uk/idid/howto, IDID list of inherited diseases, including photos.
discoveryspace.upei.ca/cidd/, Canine Inherited Disorders Database
ncbi.nlm.nih.gov/omim, Human genetic disorders database of over 2,000 diseases.
Mice strains including 1,372 human diseases with one or more mouse models.
Labs that test for genetic diseases in dogs, including PRA
1“Selection of Diseases”, vet.cam.ac.uk/idid/selection.
2Dodds, WJ. Guide to Congenital and Heritable Disorders in Dogs (Includes Genetic Predisposition to Diseases). Humane Society Veterinary Medical Association, 2011.
4“How are Defects Inherited”, discoveryspace.upei.ca/cidd/how-are-defects-inherited.
5Riehl J1, Okura M, Mignot E, Nishino S. “Inheritance of von Willebrand’s disease in a colony of Doberman Pinschers”. Am J Vet Res. 2000 Feb;61(2):115-20.
6“Progressive Retinal Atropy – PRCD, animalnetwork.com.au/tests/index.php?testid=20.
7Dostal 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.
8Clements PJ, Gregory CY, Peterson-Jones SM, Sargan DR, Bhattacharya SS. “Confirmation of the rod cGMP phosphodiesterase beta subunit (PDE beta) nonsense mutation in affected rcd-1 Irish setters in the UK and development of a diagnostic test”. Curr Eye Res. 1993 Sep;12(9):861-6.
9Kohyama M, 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]
10Moody 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]
11Zangerl 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]
12Bellumori TP, Famula TR, Bannasch DL, Belanger JM, Oberbauer, AM. “Prevalence of inherited disorders among mixed-breed and purebred dogs: 27,254 cases (1995-2010)”. J Am Vet Med Assoc 2013 242: 1549-1555.
13Bonnett BN, A Egenvall, A Hedhammar & P Olson Mortality in over 350,000 insured Swedish dogs from 1995-2000: breed-, gender-, age-, and cause-specific rates. Acta Vet Scand 2005 46 : 105-120.
14IDID: inherited diseases in dogs: web-based information for canine inherited disease genetics. Mamm Genome. 2004 Jun;15(6):503-6.