GENETIC TESTING

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.

​

Genetic testing recommended by the Dachshund Club of America this should be the BARE MINIMUM done by anyone ethically breeding Dachshunds in any size and coat.  http://www.dachshundclubofamerica.org/health/

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.    source: http://www.animalgenetics.us/Canine/cord1.htm

​

Progressive retinal Atrophy, cone-Rod dystrophy 4 (PRA-crd4) is an inherited eye disease affecting Dachshunds. PRA-crd4 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. Affected dogs can show symptoms of vision loss or have signs of retinal disease on veterinary ophthalmologic exam by 3 years of age. However, age of onset varies significantly in PRA-crd4 affected dogs, and has been reported from 1 to 15 years of age. Mutations in the RPGRIP1 gene show Incomplete Penetrance, meaning that not all dogs inheriting two copies of the Mutation develop clinical disease. This suggests that other unknown genetic or environmental factors may play a role in modifying disease development and progression. Although progression tends to be relatively slow, most affected dogs (especially those with an early age of onset) will progress to complete blindness.

​

Here is a good article on PRA and the manner in which it should be addressed by responsible breeders: http://www.fenellafleur.com/images/PRA/PRA.jpg

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 LipofuscinosisAffected 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 abnormalities.Diagnosis of Neuronal Ceroid LipofuscinosisDiagnosis 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 LipofuscinosisAt 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.source: http://www.gopetsamerica.com/dog-health/ceroid-lipofuscinosis.aspx

Here is a link to a site that discusses the DNA test available to screen for NCL: 

http://www.caninegeneticdiseases.net

​

Orthopedic Foundation for Animals (OFA) Founded in 1966, our mission is to promote the health and welfare of companion animals through a reduction in the incidence of genetic disease. The OFA website and databases provide the tools needed, whether you are a veterinarian, breeder, or prospective animal owner. https://ofa.org/

​

OFA CAER - The purpose of the OFA Companion Animal Eye Registry (CAER) is to provide breeders with information regarding canine eye diseases so that they may make informed breeding decisions in an effort to produce healthier dogs. CAER certifications will be performed by board certified (ACVO) veterinary ophthalmologists. Regardless of whether owners submit their CAER exam forms to the OFA for “certification,” all CAER exam data is collected for aggregate statistical purposes to provide information on trends in eye disease and breed susceptibility. Clinicians and students of ophthalmology as well as interested breed clubs, individual breeders and owners of specific breeds will find this useful.

​

OFA - Patella Luxation 

The patella, or kneecap, is part of the stifle joint (knee). In patellar luxation, the kneecap luxates, or pops out of place, either in a medial or lateral position.
Bilateral involvement is most common, but unilateral is not uncommon. Animals can be affected by the time they are eight weeks of age. The most notable finding is a knock-knee (genu valgum) stance. The patella is usually reducible, and laxity of the medial collateral ligament may be evident. The medial retinacular tissues of the stifle joint are often thickened, and the foot can be seen to twist laterally as weight is placed on the limb.
Patellar luxations fall into several categories:

1. Medial luxation (toy, miniature, and large breeds)

2. Lateral luxation (toy and miniature breeds)

3. Lateral luxation (large and giant breeds)

4. Luxation resulting from trauma (various breeds, of no importance to the certification process)

Numbers 1-3 are either known to be heritable or strongly suspected.

​

OFA Cardiac Exams - The clinical cardiac examination should be conducted in a systematic manner. The arterial and venous pulses, mucous membranes, and precordium should be evaluated. Heart rate should be obtained. The clinical examination should be performed by an individual with advanced training in cardiac diagnosis.

Board certification by the American College of Veterinary Internal Medicine, Specialty of Cardiology is considered by the American Veterinary Medical Association as the benchmark of clinical proficiency for veterinarians in clinical cardiology, and examination by a Diplomate of this specialty board is recommended. Other veterinarians may be able to perform these examinations, provided they have received advanced training in the subspecialty of congenital heart disease.

OFA Thyroid Exam - To identify those dogs that are phenotypically normal for breeding programs and to gather data on the genetic disease autoimmune thyroiditis.

The OFA databases are central to the organization’s objective of establishing control programs to lower the incidence of inherited disease. They serve all breeds of dogs and cats, and provide breeders a means to respond to the challenge of improving the genetic health of their breed through better breeding practices. The OFA databases are expanded as more tests become available.

​

This is a very informative link to Patellar Luxation in dogs: http://www.acvs.org/AnimalOwners/HealthConditions/SmallAnimalTopics/MedialPatellarLuxations/