Collies share Collie Eye Anomaly (CEA) with several other breeds. CEA is technically known as Choroidal Hypoplasia (CH). It is an eye disorder that causes abnormal development of the choroid – an important layer of tissue under the retina of the eye. The primary problem is choroidal hypoplasia (CH). There is under-development (hypoplasia) of the eye tissue layer called the choroid. Since the choroid layer does not develop normally from the start, the primary abnormality can be diagnosed at a very young age. The symptoms and signs can vary greatly among affected dogs within one breed, between parent and offspring and even within a litter. This creates a difficult situation for the breeder. Symptoms will develop at a young age. Within a few hours to a maximum of several weeks after birth, the characteristics that go with these genetic effects will become visible. This disease mainly affects vision, and may result in blindness. This genetic factor is inherited in an autosomal, recessive, mode. This means, that the individual can be free of the disease (homozygote normal), affected (homozygous affected) or carrier (heterozygous). Carriers may spread the mutation in a population without showing symptoms themselves. Because of this, it is extremely important to identify carriers correctly to prevent spreading of a mutation. An animal can be free and has in that situation two healthy alleles. When used in breeding this animal will not become ill due to the disease. It cannot spread the disease in the population. An animal can be carrier and has in that situation one healthy and one disease allele. When used in breeding 50 percent of the offspring will receive the disease allele. Carriers will not become ill. An animal can be affected and has in that situation two disease alleles. When used in breeding all offspring will also receive the disease allele. Affected will become ill.

Degenerative Myelopathy (DM) is a recessive autosomal neurological disorder of the spinal cord in dogs. The onset of DM generally occurs between 8 and 14 years of age. The white matter found in the spinal cord contains fibres that transmit movement commands from the brain to the limbs, and sensory information from the limbs to the brain. In dogs that have passed away from DM, degeneration of the white matter of the spinal cord is visible. The disease begins with a loss of coordination in the hind legs. Affected dogs will display an unsteady gait and may wobble when walking, knuckle over or drag their feet. As the disease progresses, the limbs will become weaker and eventually the dog will be unable to walk. If DM is allowed to progress for a longer period of time, the affected dog will be unable to hold his/her bladder and eventually weakness will develop in its front limbs. Fortunately, there is no direct pain associated with DM. It is important to note that some dogs may experience symptoms much earlier, some later and a small percentage of dogs that have inherited 2 copies of the mutation will not experience symptoms at all. Due to this the disease is not completely penetrant, meaning that a dog with the mutation is highly likely to develop the DM, the disease does not affect every dog that has the mutation. Up to date, not treatment has been developed to stop or slow the progression of DM.

Certain breeds of herding dog, such as the Australian Shepherds and many of the Collie breeds are known to show sensitivity to certain medications such as parasite-control (Ivermectin), anti-diarrhoea agents (Loperamide), chemotherapy (Doxorubicin; Vincristine; Vinblastine), sedatives (Acepromazine), heart medication (Digoxin), immune-suppressants (Cyclosporin) or pain medication (Butorphanol). This is due to a mutation that can occur in the MDR1 gene which compromises the efficacy of the blood brain barrier. This barrier, which blocks most medications from entering into the brain, is compromised by the mutation, which causes a build-up of these medications within the dog’s brain. This can lead to neurological reactions such as disorientation, tremors, blindness, involuntary muscle movement, seizures or even death. Heterozygous dogs (carriers of the mutant allele) are not affected and can phenotypically be similar to a homozygous normal dog. However, they may transmit this disease to their offspring. Unistel Medical Laboratories offers a test to determine whether dogs have mutated copies of the MDR1 gene which could result in Type 1 Multi-Drug Resistance.

Merle is a distinctive coat color and pattern brought on by a mutation in the SILV gene. It is found in several dog breeds such as the Australian Shepherd, various Collie breeds, Blue Blood Bulldogs, Great Danes, Cardigan Welsh Corgi, Chihuahua, Cocker Spaniels, Pomeranian and Dachshunds (commonly referred to as “dapple”). The coat consists of diluted base colour patches alternated by patches of full colour pigmentation. The Merle mutation can also have an effect on the pigmentation of the eyes and paw pads. Only 1 copy of the mutated SILV gene is needed to cause the Merle coat colouration. When 2 mutated copies are present it can lead to health issues such as blindness, deafness and even microphthalmia (abnormally small, barely functioning eyes). Unistel Medical Laboratories offers a test to determine whether dogs have mutated copies of the SILV gene which could result in Merle coat color.

Unistel Medical Laboratories offers DNA Typing or profiling for dog breeders, which can be used for registration purposes and parentage/relationship testing. DNA Profiling, also known as “genotyping” establishes a genetic code for individual dogs of every breed. This test does not determine breed type; rather it identifies specific gene markers that are inherited from both parents.

The panel used at Unistel Medical Laboratories for DNA typing is based on the internationally accepted panel of microsatellite markers set up by the International Society for Animal Genetics (ISAG) and are reported to ISAG 2016 standards. Our panel uses a multi-plex genetic STR marker panel consisting of 22 Loci. This creates reliable results that can be cross-compared with reports produced by other laboratories around the world, using the same methods.

Episodic falling syndrome (EFS) is a canine paroxysmal hypertonicity disorder found in Cavalier King Charles spaniels. Episodes begin between fourteen weeks and four years of age. The episodes are triggered by exercise, stress or excitement. Clinical signs may include facial muscle stiffness, stumbling, a ‘bunny-hop’ step, arching of the back and vocalization. Heterozygous dogs (carriers of the mutant allele) are not affected and can phenotypically be similar to a homozygous normal dog. However, they may transmit this disease to their offspring. Unistel Medical Laboratories offers a test to determine whether dogs have mutated copies of the BCAN gene which could result in Episodic Falling Syndrome.

Exercise induced collapse (EIC) is a recessive autosomal neuromuscular disorder.
Signs of EIC become apparent in young dogs as they encounter heavy training or strenuous exercise. Dogs that are affected with EIC can tolerate mild exercise, but display weakness and collapse after 5-20 minutes of strenuous exercise. The first symptom noted in affected dogs is a wobbly gait which may progress to a loss of control of the rear limbs. In severe cases the rear limb collapse can progress to the loss of control of all four limbs. Most collapsed dogs are totally conscious and alert, but as many as 25% of affected dogs will appear disoriented during the collapse. These collapse episodes usually last 10min and a full recovery can be seen after 30min. Dogs do not feel pain during the collapse or after recovery. In rare cases, dogs have died during exercise or while resting immediately after an episode.
Up to date, no treatment is available for this disease. Affected dogs are rarely able to continue training or competing. If strenuous exercise is removed from an affected dogs routine, they are known to continue living normal lives as pets.

Familial Nephropathy (FN) is a hereditary, progressive glomerular nephritis, which affects several breeds of dogs. Dogs with FN develop chronic renal failure, usually while they are between 6 months to 2 years of age. The clinical signs associated with chronic renal failure caused by FN are the same as those associated with chronic renal failure due to any other cause. Clinical signs that are often observed include excessive water consumption, excessive urine volume, reduced growth rate or weight loss, poor quality hair coat, reduced appetite, and vomiting. Such signs can develop insidiously and escape recognition until the degree of renal failure is so severe that overt uremia occurs. At this late stage of the disease, physical examination findings may include thin body condition, dehydration, pallor of mucous membranes, uremic breath odour, and oral ulcerations. Heterozygous dogs (carriers of the mutant allele) are not affected and can phenotypically be similar to a homozygous normal dog. However, they may transmit this disease to their offspring. Unistel Medical Laboratories offers a test to determine whether dogs have mutated copies of the COL4α4 gene which could result in Familial Nephropathy.

Haemophilia A is a coagulation disorder caused by defects in the large and complex coagulation factor VIII (FVIII) gene. The bleeding predisposition associated with haemophilia A results from a deficiency or dysfunction of FVIII, with the severity depending on the amount of residual FVIII activity. The genetic factor is continuously present, and will always be visible. The disease is inherited in an X-chromosomal manner. This means, that female individuals can be free (homozygous normal), affected (homozygous affected) or carrier (heterozygous). Male individuals carry only one copy of the X-chromosome, which results in the effect that male carriers will also be affected. Female carriers may spread the disease in a population without showing symptoms themselves. Because of this, it is extremely important to identify carriers correctly to prevent spreading of a disease.

Hereditary nasal parakeratosis (HNPK) is part of the group of diseases identified as genodermatosis. Affected dogs develop crusts and fissuring of the nasal planum at a young age but are otherwise healthy. Symptoms will develop at a young age. Within a few hours to a maximum of several weeks after birth, the characteristics that go with these genetic effects will become visible. This disease mainly affects the skin. This genetic factor is inherited in an autosomal, recessive, mode. This means, that the individual can be free of the disease (homozygote normal), affected (homozygous affected) or carrier (heterozygous). Carriers may spread the mutation in a population without showing symptoms themselves. Because of this, it is extremely important to identify carriers correctly to prevent spreading of a mutation. An animal can be free and has in that situation two healthy alleles. When used in breeding this animal will not become ill due to the disease. It cannot spread the disease in the population. An animal can be carrier and has in that situation one healthy and one disease allele. When used in breeding 50 percent of the offspring will receive the disease allele. Carriers will not become ill. An animal can be affected and has in that situation two disease alleles. When used in breeding all offspring will also receive the disease allele. Affected will become ill.

Progressive Retinal Atrophy (PRA) refers to a group of inherited blinding canine diseases. PRA is seen in many pure breeds, although the exact genetic cause is known for only a few. At present, 7 genetic PRA forms are known to affect in several dozen of breeds. In some breeds, the DNA-test is 100 percent conclusive, but in other breeds the test is based on indirect information. Research is currently going on to improve the test. As an example of the complex situation with PRA, the prcd gene is the cause of most but not all cases of PRA in Poodles. Several types are likely to be present. There appear to be at least two different genetic forms of PRA in Poodles, even though the clinical signs of PRA in all diseased dogs look the same.

Von Willebrand disease (vWD) is the most common inherited bleeding disorder, which is highly heterogeneous ranging from an asymptomatic laboratory abnormality to a life threatening bleeding. The condition is caused by a quantitative or qualitative deficiency of von Willebrand factor (vWF). It has been classified into six subgroups based on evaluation of the vWF level and function. The disease is characterized by the abnormally low production of von Willebrands factor which plays a key role in the complex process of clotting a damaged blood vessel. Because it is very uncommon for carriers to show symptoms of vWD this condition is considered to be recessive. This disease results in a reduced clotting of blood. As a result, affected individuals will show increased bloodflow during injuries. This genetic factor is inherited in an autosomal, dominant, mode. This means, that the individual can be free of the mutation (homozygote normal), affected (homozygous affected) or carrier (heterozygous affected). Both carriers and affected individuals will show symptoms of the mutation. An animal can be free and has in that situation two healthy alleles. When used in breeding this animal will not become ill due to the disease. It cannot spread the disease in the population. An animal can be carrier and has in that situation one healthy and one disease allele. When used in breeding 50 percent of the offspring will receive the disease allele. Carriers will also become ill. An animal can be affected and has in that situation two disease alleles. When used in breeding all offspring will also receive the disease allele. Affected will also become ill.