|Here you will find information on the importance of genetic testing, the types that are available to the Dachshund
breed. Including, what those test cover, why the are of importance not only to the bettering of the breed, but also
what they mean to a puppies potential new family.
There are amazing strides being made in the world of genetic testing, and more and more veterinarians are
counseling potential puppy buyers on the importance of these tests. Although some of these tests are relatively new,
they are able to give us information that we can use to produce the best genetically sound puppies possible. I
believe strongly that temperament is very important, however we now can strive for the best of both, a puppy bred
for amazing personality, coupled with the best genetics we can produce.
Progressive Retinal Atrophy, more commonly known as PRA, is a general term for a group of diseases causing
degeneration of the retina, leading to a loss of vision. One form of this disorder is known as cord1-PRA, which stands
for cone-rod dystrophy-PRA. Cord1-PRA is a genetic disorder associated with a recessive mutation in the RPGRIP1
gene, which codes for an important photoreceptor protein in the eye. Like many forms of PRA, cord1-PRA is breed
specific, and is known to occur in Miniature Dachshunds and English Springer Spaniels.
Cone-rod dystrophy first affects the cones in the retina, which are the photoreceptors responsible for detecting
bright light or daylight. Rods, or low-light photoreceptors, begin degenerating secondarily. This is different than
other forms of PRA, such as prcd-PRA, in which the rods are affected first, followed by the cones. Unfortunately,
most dogs affected by cord1-PRA will eventually become blind, and there is no cure at this time.
The age of onset can vary with this disorder, some dogs will first begin experiencing problems around 6 months in
age, though the average age of onset is around 5 years of age. A small percentage of dogs do not experience any
symptoms until as late as 10 years of age. It is not yet known why some dogs will experience late-onset PRA,
however, it is likely due to the presence of other genetic modifiers that have not been determined at this time.
Because this disorder is recessive, a dog must have two copies of the mutated gene to exhibit symptoms associated
with PRA. A dog can be a carrier of cord1-PRA, meaning it only has one copy of the mutation, and not show any
outward signs of retinal degeneration. A carrier can still pass on the mutated gene to any offspring; mating two
carrier dogs can produce offspring affected by cord1-PRA.
Here is a good article on PRA and the manner in which it should be addressed by responsible breeders:
Neuronal Ceroid Lipofuscinosis (NCL)
Lysosomal storage diseases of the central nervous system represent a group of disorders which have in common the
accumulation of metabolic by-products in neurons. Storage diseases can primarily affect the cerebellum, but they
usually affect multiple areas of the brain and spinal cord. Animals with lysosomal storage diseases affecting the
cerebellum typically are young, due to the fact that these diseases are congenital. There are several documented
lysosomal storage diseases. Neuronal ceroid-lipofuscinosis (NCL) has been most commonly reported in dogs. A similar
condition affects cats. The disease results from intraneuronal accumulations of ceroid-lipofuscin granules. It has
been related to primary cerebellar disease in the dog and can result in cerebellar atrophy.
Dogs with this storage disease are usually less than 1 year old; however, they may not show clinical signs until they
mature. The majority of dogs begin to exhibit signs of an abnormality between 12 and 18 months of age.
Signs of Neuronal Ceroid Lipofuscinosis
Affected dogs present with behavior change and circling. The disease progresses over 2-3 years to include poor
movement incoordination, difficulty in swallowing, vision and hearing loss, rapid motion of the eyeball (nystagmus),
and voice changes. Enlargement of the nerves of the forelimbs can be detected, which is due both to fluid
accumulation and infiltration of the nerves. At a later stage, signs of the disease include seizures, tremors, and gait
Diagnosis of Neuronal Ceroid Lipofuscinosis
Diagnosis of ceroid lipofuscinosis is based upon clinical signs, especially in a susceptible breed. Cerebrospinal fluid
analysis is usually normal but may reveal increased protein levels with a normal cell count. Computed tomographic
(CAT) or magnetic resonance imaging (MRI) of the brain of dogs with ceroid lipofuscinosis may reveal
abnormalities, such as brain atrophy and abnormal brain-tissue density. Definitive diagnosis will require additional
skin and/or blood tests.
Prognosis for Neuronal Ceroid Lipofuscinosis
At present, the prognosis for the lysosomal storage diseases in dogs and cats is grave. For the majority of these
disorders, affected animals are euthanized due to progressive worsening neurological dysfunction within the first
year of life. For the more slowly progressive disorders (ceroid lipofuscinosis), continuous neurological dysfunction
leads to death or euthanasia usually within 1-2 years of diagnosis. Despite the poor outlook for these disorders, bone
marrow transplantation and lysosomal enzyme replacement therapy have been successful in some human and animal
cases. Gene transfer therapy is also being actively investigated and will hopefully be available in the future.
Here is a link to a site that discusses the DNA test available to screen for NCL:
Canine Eye Registry Foundation (CERF)
"Dedicated to the elimination of heritable eye disease in purebred dogs through registration and research."
Orthopedic Foundation for Animals (OFA)
While the OFA continues to focus on hip dysplasia, today’s OFA Mission, “To improve the health and well being of
companion animals through a reduction in the incidence of genetic disease,”
This is a very informative link to Patellar Luxation in dogs:
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