Miniature Schnauzer Health
The health and happiness of our dogs here at Wowzers is our utmost priority and that's why we know the DNA status for hereditary disease of each of our family members. Miniature Schnauzers are a relatively healthy breed. The discovery of DNA genetic testing has made it much simpler for a breeder to produce healthy puppies.
There are 6 main hereditary health issues when it comes to the Miniature Schnauzer. These are known as Factor VII Deficiency, Mullerian Duct Syndrome, Myotonia Congenita, Spondylocostal Dysostosis and Type A PRA 1 and 2.
Factor VII Deficiency.
Factor VII deficiency is a blood clotting disorder that causes excessive or prolonged bleeding after an injury or surgery. With factor VII deficiency, your body either doesn’t produce enough factor VII, or something is interfering with your factor VII, often another medical condition. Factor VII is a protein produced in the liver that plays an important role in helping your blood to clot. It’s one of about 20 clotting factors involved in the complex process of blood clotting. To understand factor VII deficiency, it helps to understand the role factor VII plays in normal blood clotting.
Mullerian Duct Syndrome.
Mullerian Duct Syndrome (MDS) is an inherited disorder of sexual development affecting male dogs. In early in-utero development all canine fetuses have precursors of the uterus, fallopian tubes and upper vagina called Mullerian ducts. In normal male fetuses, the Mullerian ducts regress as sexual differentiation occurs in-utero, allowing for development of male sexual anatomy. In affected male dogs the female reproductive organs fail to regress in-utero. Approximately half of the affected male dogs have externally normal testes and are fertile, but internally have remnants of female reproductive organs, including the uterus. The other 50% of affected male dogs have Cryptorchidism in addition to remnants of female reproductive structures. Cryptorchidism predisposes dogs to infertility and testicular tumors. Affected dogs may also have small testes. Female dogs may need to have a Hysterectomy if the uterus becomes infected. Females with this condition have normal internal and external female anatomy.
Myotonia Congenita.
This is an uncommon condition that causes gait abnormalities (e.g. bunny hopping) in puppies. Muscles become enlarged (hypertrophied), and this is especially noticeable in the shoulder and thigh areas. The tongue is enlarged and may protrude from the mouth. There may be a stiff gait, especially in the hindlimbs, and affected animals may have difficulty getting to their feet and balancing. Signs are usually evident at a young age. This condition occurs in several breeds, most commonly in the chow chow and miniature Schnauzer. In the miniature Schnauzer the condition is autosomal recessive and the mutation has been characterised, with a DNA test available. In people recessive and dominant forms are seen. The condition occurs due to a mutation in a gene that controls the muscle membrane ion channels (i.e. the gates that control flow of sodium and chloride across the muscle cell wall). This abnormality delays the relaxation of the muscle fibre so that in effect the muscles are overly tensed, leading to the increase in their size and decreased muscle control that is seen. Diagnosis is made by electromyography (studies of the passage of electrical impulses through the muscle tissue) and muscle biopsy. The condition can be treated (not always successfully) with membrane stabilising drugs (that act to block the sodium or chloride channels) but cannot be cured.
Spondylocostal Dysostosis.
Musculoskeletal - Associated with muscles, bones and associated structures.This disease can cause some discomfort and/or dysfunction in the affected animal. It does not generally affect life expectancy.
Type A PRA 1.
Progressive retinal atrophy (PRA) is a collection of inherited diseases affecting the retina that cause blindness. Each breed exhibits a specific age of onset and pattern of inheritance, and the actual mechanism by which the retina loses function can vary. The result of almost all types of PRA is similar - generally an initial night blindness, with a slow deterioration of vision until the dog is completely blind. The age at which the dog becomes fully blind also varies, depending on the genetic disruption present and the breed. Affected eyes are not painful, unless complicated by a secondary problem, such as cataract or uveitis (inflammation due to a leaking cataract). Progressive retinal atrophy (PRA) has been classified in several different ways. The simplest of these is by age of onset. Early onset PRA occurs when the affected dog is night blind from birth, and generally is completely blind between 1 - 5 years of age. Late onset PRA is where the dog is night blind at some time over 1 year of age, and full blindness will occur at a somewhat later stage in life. Another is by the type of genetic abnormality causing the PRA. PRA may be inherited by recessive, dominant or sex-linked mechanisms in dogs. For many types of PRA in many breeds a DNA test is now available to allow for easy screening for the disease. Despite the complexity of the disease and its many forms, ultimately all forms have one thing in common – degeneration of the retina causing progressive loss of vision. DNA tests are not yet available for all affected breeds. And because breeds may also be prone to several forms of PRA (and not all may have a genetic test available) examination of the retina by a veterinary ophthalmologist remains a mainstay of the diagnostic testing regimen. In some breeds with a late onset PRA, serial eye examinations may be required before the signs of retinal degeneration become apparent. The electroretinogram (ERG) is a diagnostic test that the veterinary ophthalmologist may choose to use in some cases and is a very sensitive method of detecting loss of photoreceptor function. An ERG can be a very good screening test for puppies that may have an early onset form of PRA. The miniature Schnauzer suffers from a rare form of PRA called PRA type A. This was previously known as photoreceptor dysplasia, where there is a defect in the differentiation of the rods and cones after birth. This leads to a fairly rapid degeneration of the rods and cones, although vision is maintained for longer period of time than would be expected, often a number of years. Affected animals may not show signs until they are 3 - 5 years of age.
Type A PRA 2.
Type A PRA is a difficult form of retinal atrophy as it can be partially dominant; some carrier animals appear partially affected when examined clinically. An abnormal shine may be apparent in the dog’s eyes as a result of increased pupil dilation, as the eye attempts to let in more light. The pupil will appear dark and glossy, and will not respond as quickly to light as an unaffected dog. Disorientation is also common symptom of PRA, particularly at night due to the degeneration of the light sensitive rods specializing in dim light perception. Initial night blindness in most cases will progress slowly to day blindness also as the cones in the eye that respond to bright light are progressively damaged. Sadly, like humans, there is no treatment or cure for blindness in dogs.