Health Issues in the Border Collie
Welcome to our section on health issues in the border collie.
When I first started out in Border Collies and started investigating these issues I was needless to say “blinded” by the science of it all, even now looking at them I am still rather blinded by it so I have undertaken to explain it in simple terms that all can understand and save you the bother of being blinded also!
I must STRESS at this point that testing is the simple part and not at all where it stops in producing a healthy pedigree dog. Line history cannot have enough emphasis placed on it. For all the testing in the world if you have no line history pertaining to heritable diseases then you are breeding from a wildcard.
While this may all appear quite dire, the Border Collie on the whole is a very healthy and robust breed next to many and many of the untestable diseases can afflict most any breed of dog.
There are two sections to discuss. The first being testable disease traits and the second currently untestable disease traits.
Section 1 - Testable Genetic Disease Traits
Most of the conditions below are autosomal recessive meaning that at least both sire and dam must carry one copy of the defect gene to produce affected progeny; hence there are three status of each condition:
Clear/Normal – (genotype N/N), this means that the dog does not carry the defect gene therefore can never be affected by, carry or pass on to its offspring. This dog can effectively be mated to any other dog.
Carrier – (genotype N/n), this means that the dog carries just one copy of the recessive defect gene not the two required for affected. This dog will never be affected by the disease but carries it so can pass the defect gene on to its offspring. This dog should only ever be mated with a clear/normal dog and they must be kept in the genepool to aid genetic diversity in the breeds.
Affected – (genotype n/n), this means that the dog carries two copies of the recessive defect gene. This gene will ALWAYS be passed onto the offspring. This dog should never be mated.
I have highlighted where a condition is NOT autosomal recessive but rather dominant or autosomal dominant. Information taken from Genoscoper Labs, MyDogDNA.
Collie Eye Anomaly (CEA)
The mildest form of the disease is choroidal hypoplasia (CH). Choroidal hypoplasia is non-progressive and usually does not cause visual deficits on its own. Mild changes associated with this disease are typically best visualized with ophthalmoscopy in puppies before 10 weeks of age. Colobomas occur in a more severe form of the disease. Colobomas of the optic disc are excavations of the optic disc surface. Large colobomas may lead to reduced vision while smaller ones have little effect on vision. Retinal detachment or bleeding inside the eye can develop in severely affected dogs as a secondary complication of coloboma. This can cause loss of vision. Sometimes the eyeballs of affected dogs can be distinctly smaller in size than normal.
Neuronal Ceroid Lipufuscinoses (NCL)
NCLs are a group of inherited progressive neurodegenerative lysosomal storage disorders. Neuronal ceroid lipofuscinoses are characterised by excessive accumulation of lipofuscin and ceroid lipopigments into central nervous system and other tissues. Different forms of NCL differ by age of onset and pattern of progression. Usually progressive loss of vision is the first observable symptom. In addition, the clinical signs of NCL include ataxia (uncoordinated movements), seizures and behavioural changes, such as aggression. Type 5 form of NCL is encountered in Border Collie.
Trapped Neutrophil Syndrome (TNS)
Neutrophils are white blood cells that play a key role in activating the immune system. In TNS, blood cells fail to be released from the bone marrow, which results in low neutrophil numbers circulating in the blood. As a consequence, the dog is exceptionally susceptible to infections and suffers from chronic inflammatory conditions such as arthritis. Clinical signs are usually observed at the age of 6 to 12 weeks. Affected puppies are often smaller than their littermates and described to have ferret-like facial features due to an abnormal craniofacial development with narrowed, elongated skull shape. For some affected dogs, clinical signs can be mild and go unnoticed until adulthood. Nevertheless, TNS is a severe disease and affected dogs have a shorter life expectancy.
Dental Hypermineralisation (Raines Disease)
The disorder causes brownish dental discolouration and abnormal wear of teeth. As the teeth wear, the biting surfaces of the teeth darkens, become dark brown in colour; the enamel layer may also show a light brown discolouration and appear dull. The disorder causes severe tooth wear leading to pulp exposure, chronic inflammation of the pulp, and pulpal necrosis. Histologically, dentin of affected dogs has an abnormal structure and the enamel can be slightly hypoplastic. Affected dogs require regular dental treatment.
Degenerative Myelopathy (DM)
DM is neurodegenerative disease of the spinal cord that is primarily seen in adult German Shepherd Dogs but many other breeds have been reported to also be affected. Affected dogs first begin by exhibiting muscle wasting, proprioceptive deficits, and knuckling of the hind feet. Though the condition is not painful, affected dogs will eventually require assistance walking. As the condition progresses, it moves up the spinal cord and the dog’s neurologic deficits mirror the progress, losing fecal and urinary continence and eventually involving the front legs and the brainstem. Euthanasia is usually elected.
Goniodysgenesis and Glaucoma
Goniodysgenesis and glaucoma in Border Collie (GDD) is a hereditary disorder affecting the eyes. Primary glaucoma is a hereditary ocular disorder affecting intraocular fluid circulation and causing increased intraocular pressure. The elevated intraocular pressure damages the optic nerve and retinal cells and leads to blindness if untreated. Glaucoma can be preceded by goniodysgenesis, which is a developmental abnormality of the anterior chamber of the eye that has been associated with glaucoma and blindness. Glaucoma affects multiple breeds, but in most cases the causative mutation has not been identified.
Imerslund-Gräsbeck syndrome (IGS)
Cobalamin or vitamin B12 is required for normal function of many enzymes. Cobalamin is stored in the body before birth, but once those stores are consumed early in life, cobalamin must to be acquired from food. Initial signs of intestinal cobalamin malabsorption can be seen in puppies 6-12 weeks of age. Puppies with IGS suffer from weakness and loss of appetite and fail to grow normally: anaemia, neutropenia, and low cobalamin concentrations are present. High levels of homocysteine and methylmalonic acid can also be observed in the blood. Proteinuria is observable in the urine sample.
Early Adult Onset Deafness (EAOD)
Early Adult Onset Deafness (EAOD; also known as Adult Onset Deafness [AOD] or Early Onset Deafness [EOD]) is an autosomal recessive hearing disease that is relatively common in Border Collies. The gradual hearing loss is observed usually at the age of 5 to 7 years affecting both ears.
Sensory Neuropathy (SN)
The disorder is caused by the degeneration and loss of nerve fibers in sensory, and to a smaller extent motor, nerve fibers. The prognosis is grave. Clinical signs are detectable in puppies from two to seven months of age. Clinical signs include incoordination of gait (ataxia), knuckling of the paws, hyperextension of the limbs, and self-mutilation of the limbs. The hind legs are usually most severely affected. Loss of sensation is progressive and affects all limbs. Urinary incontinence and regurgitation can occur in the later stages of the disorder.
Cystinuria Type II-A
Dogs with cystinuria are not able to reabsorb the amino acid cystine in their kidneys and therefore high concentrations can accumulate in the urinary tract causing formation of cystine crystals and stones that can obstruct the urinary tract. While cystinuria has been reported in a number of breeds, this variant is known to cause the condition in Australian Cattle Dogs. Several mutations have been shown to cause the condition and the inheritance pattern varies between them. This variant is known to be inherited in an autosomal dominant fashion.
Myotonia is a muscular disorder caused by a defect in ion channels of the skeletal muscles which leads to delayed relaxation of skeletal muscles following contractions. The clinical signs can be seen in puppies only a few weeks old. An affected dog suffers from muscle hypertrophy and has stiff movements. It can have difficulties rising after rest and in rapid changes of posture. The disorder is characterised by a bunny-hopping gate. An affected dog may also suffer from superior prognathism (protrusion of one or both jaws), ptyalism (excessive flow of saliva), dental abnormalities, and increased respiratory sounds during exercise. The tongue of affected dogs is enlarged and stiffens when touched.
Multi-drug resistance 1 (MDR1)This is a genetic mutation that alters a dog's ability to limit the absorption and distribution of many drugs. Affected dogs are slower to eliminate drugs from the body and can suffer side effects when exposed to certain medications. This mutation is sometimes also called "ivermectin sensitivity". However, the name is a misnomer as several other drugs pose a risk to MDR1 positive dogs. Adverse reactions can occur when affected dogs are exposed to some common drugs such as acepromazine, butorphanol, and macrocyclic lactones. However, all FDA approved heartworm preventatives are safe to administer to MDR1 positive dogs. This mutation is inherited in a dominant fashion though dogs with two copies of the mutation will exhibit more severe clinical signs.
- Autoimmune Disease
- Discoid Lupus
- Systemic Lupus
- Addisons Disease
- OCD - Osteochondritis Dissecans
- HD - Hip Dysplasia (I know right, you thought this one was cut and dry)
- Cruciate Disease
- Border Collie Collapse
Pemphigus has 4 different types:
- Foliaceus - affects the head, ears, footpads and body, characterised by swollen lymph nodes.
- Erythmatosus - similar to Foliaceus but confined to head, ears and footpads.
- Vulagris - affects the gums, lips and skin particularly underarm and groin but with very deep ulceration and anorexia.
- Vegetans - pustule groups, non generalised join to form larger pustule groups.