Tag archives: blindness

In this second part of a four part blog series examining preventable inherited diseases of the Labrador retriever (see part one here) we will be examining two diseases known to cause dwarfism in the breed.

Skeletal Dysplasia 2

Skeletal dysplasia 2 (SD2) is an inherited disease of collagen resulting in disproportionate dwarfism in the Labrador. Disproportionate dwarfism is marked by abnormal size discrepancies between the limb length of affected individuals and the size of their torso. In the case of SD2, the limbs of affected dogs tend to be shorter than normal despite an average sized torso. International breed standards of the Labrador list shoulder heights of 56-57 cm in males and 54-56 cm in females. In the publication describing the COL11A2 gene mutation associated with SD2, the authors found that most of the affected males had shoulder heights of less than 55 cm and most affected females showed heights of less than 50 cm. However, there is some overlap of shoulder heights between those of normal dogs from blood lines of smaller size and affected dogs from larger sized blood lines. Though the front limbs tend to be more severely affected (and sometimes slightly bowed) with SD2, the long ...

Thanks to our loyal and dedicated clients, Paw Print Genetics continues to increase test offerings in 2015! To start our year off right, we released DNA profiling and parentage testing, seven long-awaited canine coat color tests, and four tests for other specific traits of the hair coat and tail. In addition, Paw Print Genetics continues to expand upon the largest canine inherited disease testing menu in North America by releasing 10 new inherited disease tests. One newly added test that will make many Labrador retriever owners happy is the test for an inherited disease known as retinal dysplasia or the more apt term, oculoskeletal dysplasia (often written as retinal dysplasia/oculoskeletal dysplasia 1 or abbreviated, RD/OSD 1). In March of 2014, RD/OSD 1 became a little more personal for Paw Print Genetics when we had the honor of meeting Frank, an adorable, blind RD/OSD 1 affected Labrador retriever living at the Double J Dog ranch in Hauser Lake, Idaho. We are excited to launch a test that allows breeders of sweet dogs like Frank to produce puppies free of this severe and challenging disorder!

RD/OSD 1 is a genetic disease of collagen caused by a mutation ...

After many inquiries by our wonderful clients, Paw Print Genetics is excited to announce that we have begun testing for two genetic mutations reported to cause progressive retinal atrophy in the golden retriever. Known specifically as progressive retinal atrophy, GR1 and GR2 (PRA-GR1 and PRA-GR2), these two diseases were found to be caused by genetic mutations in the SLC4A3 and TTC8 genes, respectively. In addition to the golden retriever, the TTC8 mutation that causes PRA-GR2 has also been identified in a clinically affected Labrador retriever.

Progressive retinal atrophy (PRA) is not a single disease, but rather a group of inherited diseases each caused by different genetic mutations in different genes. The various forms of PRA affect over 100 different dog breeds. Though there are variations in the progression of disease, most varieties of PRA (regardless of genetic cause) result in blindness due to an inherited degeneration of the retina; more specifically, the degeneration of retinal cells known as rods and cones, which play an important role in vision.

In PRA-GR1 and PRA-GR2, signs of night blindness and loss of peripheral vision are seen first with progression to complete blindness occurring over time. In addition, they are both considered late onset ...

One of the hottest questions from our loyal, Paw Print Genetics clients over the past several months has been, “When are you going to offer genetic testing for hereditary cataracts?” After much preparation and anticipation, we are happy to report that Paw Print Genetics has begun testing for two different mutations of the HSF4 gene reported to cause hereditary cataracts (HC) in seven different breeds of dog.

Cataract is the term used to describe a condition in which opacities develop in the normally clear lens of the eye. The lens is responsible for focusing light onto the retina in the back of the eye resulting in acute, focused vision. With cataracts, the lens cannot focus light appropriately. This results in progressive vision deficits as the cataract increases in severity. While many cataracts identified in dogs are caused by non-inherited causes (e.g. UV radiation, infections, diabetes, chronic inflammation of the eye), as the name suggests, HCs are those passed from generation to generation. In addition, inherited genetic mutations are the most common cause of cataracts in dogs. However, by performing genetic testing on dams and sires prior to breeding, selective breeding precautions can be taken to prevent affected puppies ...

With their picturesque appeal, predecessors of the modern day papillon (known as continental toy or Titian spaniels) were popular subjects for European painters between the 16^th and 18^th centuries. The popularity of these small spaniels with European aristocrats and royalty of the Renaissance period, led to their appearance in many paintings from the era. The iconic, longhaired “butterfly-like” ears, for which papillons are named, are obvious in these paintings though many of the portrayed dogs were of the drop-eared variety of the breed that today is known as the phalène. According to an article on the Papillon Club of America website, in the late 19^th century erect ears became a more desirable trait with papillon fanciers and eventually the erect-eared variety obtained their current position as the more popular form of the breed. In addition to their beautiful physical attributes, in their modern form, well-socialized papillons are described as happy, playful and affectionate family members. Papillons are also often described as frequent barkers, making them great guard dogs. Despite their adorable personalities and good temperament, like other purebred dogs, the papillon is known to inherit some genetic diseases that could prevent this regal breed from reaching the ...

The intelligent, prey-driven English springer spaniel (ESS) has forged its path as a popular, hardworking companion for bird hunters while maintaining a loyal and affectionate personality suitable to family life. Until the early 1900’s, springer spaniels were produced in the same litters as cocker spaniels; springers were chosen from the largest puppies of the litter and were trained for flushing or “springing” game while the smaller littermates were labeled cocker spaniels and were trained for hunting the elusive woodcock. Since then, springer spaniels have been further split into the generally leaner, shorter haired field (hunting) variety and the denser boned, densely haired show (“bench”) line. Unfortunately, like other purebred dogs, English springer spaniels are known to inherit genetic diseases that can keep some individuals from reaching the great potentials for which the breed is capable. One such inherited condition is an eye disease known as progressive retinal atrophy, cone-rod dystrophy 4 (PRA-crd4) caused by a mutation in the RPGRIP1 gene.

Progressive retinal atrophy (PRA) is not a single disease, but rather a group of inherited diseases each caused by different genetic mutations in different genes. The various forms of PRA affect over 100 different dog breeds. Though there are variations ...

Basenjis are an ancient, charming and unique breed originating in Africa. According to the Basenji Club of America, dogs resembling basenjis have been found in African cave paintings and Egyptian art dating back to between 1000 and 6000 BC. In the late 1800’s, the German botanist and ethnologist, Georg Schweinfurth described a domesticated dog closely resembling the Basenji belonging to native people of central Africa that he had encountered on his trips to the region. Shortly after this description was published, dogs resembling Basenjis were exported from Africa and displayed in Great Britain and Berlin as “Lagos Bush Dogs” and “African Bush Dogs” respectively. Despite their unique and desirable characteristics (such as their yodel-like vocalization known as a baroo), basenjis are similar to other dog breeds in the sense that they are known to inherit a handful of genetic diseases that can cause significant issues in breeding programs. Luckily for the basenji, genetic tests are now available through Paw Print Genetics to help breeders prevent future generations of dogs from being born with some of these preventable illnesses. The two inherited disease tests recommended by the Basenji Club of America and of great importance for basenji breeders have been the ...

Neuronal Ceroid Lipofuscinosis (NCL) is a group of inherited mammalian diseases characterized by abnormal accumulations of a metabolic byproduct known as lipofuscin in nerve cells and various organs of the body.  The accumulation of lipofuscin eventually leads to progressive nerve cell dysfunction and severe neurological symptoms including behavioral changes, balance issues, muscle atrophy, uncoordinated movement, blindness, head tremors and seizures.  Other organ systems can also be affected to various degrees depending on the severity of lipofuscin build up.  Most dogs will die due the disease or are euthanized when neurologic problems progress to the point of preventing normal daily activities.  While most types of NCL begin to cause clinical signs around 1 to 2 years of age in dogs, the age of onset and speed of progression vary significantly upon the type of NCL.  Variable presentation and progression among NCL types is expected given that multiple genes can cause this clinical condition.

Unfortunately, details about disease incidence and prevalence within a breed are often difficult to obtain including NCL.  Without going into an in-depth discussion about statistics, among other conditions, in order to estimate incidence and prevalence of disease for an entire population, individuals ...

As most canine breeders can tell you, some of the diseases most commonly tested for in pure bred dogs are the eye diseases falling under the general term, Progressive Retinal Atrophies (PRA).  However, because the various types of PRA can present very similarly, many people are unaware that PRA is not just one disease, but is a general category of disease known to be caused by a number of different genetic mutations in several different genes.  The prevalence of each type of PRA varies by breed and some forms have only been identified in a single breed.  In addition to confusion regarding the variety of disorders grouped under the PRA label, there is often confusion regarding the method used to name the individual types of PRA seen.  A good place to start in understanding the common names of these diseases would be to look at the general types of the disease and how they manifest.  In order to understand the various types however, we must first learn a little about how the eye works.

The retina is a light-sensitive layer of sensory tissue that lines the inner surface of the eye.  Light that shines ...

Just like people, blindness or an otherwise significant reduction in vision is a relatively common occurrence in our canine friends. Whether your puppy loses his sight in bright light or your old faithful companion’s eyes are looking a little "cloudy", the profound impact it can have on the life of both pet and owner, makes preventing or treating eye disease a major concern for veterinarians.

Though there are hundreds of possible biological processes responsible for blindness, these processes can be grouped into two major categories: Non-genetic (acquired disease) and genetically inherited disease caused by mutations in a dog’s DNA (the genetic material found in all cells). Though mutations in DNA are present at birth, disease can present in a variable timeframe from puppy to older dog, depending on the specific mutation present.

Though not all eye diseases have an inflammatory component to them, some of the most commonly acquired, non-genetic eye diseases involve chronic inflammation of the eye’s internal and external structures. External chronic eye inflammation gradually damages the structure of the cornea and can eventually lead to difficulty seeing. Most of the cases involve physiological abnormalities (i.e. eyelashes rubbing on the eye) or trauma resulting ...