Tag archives: choroidal hypoplasia

Since we started working with the Boykin Spaniel Society (BSS), both Paw Print Genetics (PPG) and the BSS have learned much about the genetic disease concerns of these wonderful, little brown dogs. By using the founder breeds of the Boykin as a guide, PPG developed the first Boykin spaniel inherited disease testing panel in 2014. Based upon the results collected over two years of testing Boykins, in September 2016, the original disease testing panel was split into two panels; the Boykin spaniel essential panel (containing the most clinically important and/or common diseases) and the supplemental panel (containing diseases of less clinical importance and/or lower incidence).

Two of the four diseases on the Boykin spaniel essential panel are inherited diseases of the eye. Diseases resulting in vision loss or blindness are among some of the most life-altering and troublesome non-lethal diseases of dogs. However, with knowledge of a specific genetic mutation resulting in blindness as well as an understanding of how that specific eye disease is inherited, blindness caused by the mutation can be prevented through the use of genetic testing and informed selective breeding practices based upon test results. Two eye diseases known to be inherited in the ...

Despite a name which implies an origin “down under”, the Australian shepherd is widely understood to be a breed of American origin. In fact, descriptions of the breed and their importance in the lives of 19^th and 20^th century Basque shepherds who had relocated from Australia to the western US are plentiful. Australian shepherds’ exceptional intelligence, versatility, desire to please, and a natural instinct to herd and guard livestock have made them a common inhabitant of ranches and farms where they have been trained to perform a variety of tasks. Aside from their work on the homestead, their unique abilities have also made them great competitors in stock dog trials, agility events, and other dog sports. Despite their many talents and desirable traits, like many other breeds, the Australian shepherd has developed some inherited disease concerns that can prevent them from performing at their best or otherwise decrease their overall quality of life. One such condition recognized in the Australian shepherd is the genetic eye disease known as collie eye anomaly.

What is CEA?

Collie eye anomaly (CEA), also known as choroidal hypoplasia, is an inherited eye disease caused by a mutation in the canine NHEJ1 gene. Dogs ...

In 1953, a prevalent inherited eye condition of collies was first described by W.G. Magrane in a journal article entitled, “Congenital anomaly of the optic nerve in collies”¹. Later termed choroidal hypoplasia by scientists, the disease now known to the general public as collie eye anomaly (CEA) has significantly troubled collie breeders for over 50 years. In 2007, a paper describing a specific genetic mutation of the NHEJ1 gene associated with CEA was published. Identification of this mutation, has made it possible for scientists to develop tests that predictably identify the mutation and subsequently help breeders avoid producing puppies with CEA. Despite its breed specific name, testing has since identified the same CEA associated mutation in several other dog breeds including the Australian shepherd and the Shetland sheepdog.

Though there is significant variability in terms of ocular defects seen in affected dogs, the fundamental characteristics of CEA stem from the malformation of an important structure of the eye known as the choroid. The choroid is a thin layer of tissue containing the blood vessels responsible for supplying blood and nutrients to the retina and other structures of the eye. While mildly affected dogs may maintain normal vision with ...