Progressive retinal atrophy (PRA-prcd) & Black hair follicular displasia (BHFD)

New tests have been added to the Tenterfield Terrier Profile recently and they are as follows:

Progressive retinal atrophy (PRA), also known as progressive rod and cone degeneration (PRCD) which is often abbreviated to just PRA-prcd or just PRA. PRA is a group of degenerative eye disorders that causes blindness in both eyes over time. ‘As its name implies, this blindness is caused by the gradual deterioration and loss of function in the retina and its photoreceptors: rods and cones. The membranous retina lines the back of the eyes and absorbs, reflects, and perceives light. A dog affected by PRA-prcd, therefore, ’loses its ability to see clearly as the membrane deteriorates.’ .
As per the research done on autosomal recessive genes to end up with an affected pup you need to obtain a double-up of the defective gene. That is, both parents must be carriers. Consequently, if only one of a breeding pair is a carrier, they will never produce an affected pup, but may produce puppies that may be carriers. Carrier puppies do not develop the disease themselves and will not exhibit any abnormalities throughout their lives but can pass the gene mutation on to the next generation. Therefore if breeders are mating a carrier to a clear, this will result in approximately 50/50 ratio of carrier & clear puppies. We therefore ask, if you are considering buying a breeding bitch or dog please consult us further about your options for testing your puppy before purchase. Affected pups are where two copies of the PRA-prcd gene are present, blindness will develop over time.
As responsible breeders, we are obligated by the ANKC code of Practice to do all we can to identify and eliminate inheritable diseases and we do this by making informed breeding choices and therefore all pairing’s are genetically tested before the matings have taken place, however it is also important to remember that PRA-prcd is not a death sentence and since vision loss is gradual in most circumstances most dogs learn to adapt and go on to live happy, fulfilling lives.

Black hair follicular dysplasia (BHFD) is a genetic inheritance of an autosomal recessive TRAIT. Dogs who are AFFECTED by BHFD start losing their black hair early in life, usually around one month old and progresses at a slow rate from there. Generally, all of the hair is lost in black coloured areas of the coat by 8 to 9 months of age and although this condition doesn’t affect a pups health much beyond the hair loss it can leave the skin more highly susceptible to bacterial skin infections.
Unlike CHG, PLL & PRA which are all autosomal recessive diseases, BHFD is a recessive TRAIT so what is the difference?
This is a very difficult question to answer but I will try without trying to bog you down in genetic talk that sometimes just leads to more questions than answers. What we do know is that Autosomal Recessive DISEASE testing (such as CHG,PLL & PRA) allows us, as breeders, to know which of our dogs have carrier genes allowing us to effectively eliminate breeding affected pups of diseases.
Unfortunately though Autosomal Recessive TRAIT testing, is not so straightforward, as parents can still have two carrier genes but never show signs of being affected. In fact, many breeders have experienced a high percentage of BHFD double carrier gene dogs which have never expressed black hair loss above the usual seasonal shed. Therefore as breeders, we continue to share information with each other and maybe in the future, we can endeavour to hope to understand more about the recessive trait of BHFD and hone in, on which alleles are resulting in AFFECTED pups.
So what does this mean for you as a potential puppy owner? Alaula Tenterfield Terriers will genetically test, when the parents are double carrier dogs, ALL pups for BHFD only, so you can have an informed decision when choosing a pup from one of these litters.
Why are we still breeding BHFD double carrier bitches you may ask? Unfortunately, we are seeing a high percentage of our ‘dilutes’ so liver and blue dogs that are testing positive as double carrier dogs and as the gene pool for quality breeding ‘blue’ Tenterfield’s especially are very limited at present, we continue to breed to expand this gene pool against ‘clear’ studs in hopes to one day have a breeding pool of clear bitches.

If you wish a more comprehensive explanation for these additional tests please see—full-breed-profile and click on the appropriate test for an overview.

Please Note: At Alaula all our bitches are tested for all genetic tests available for Tenterfield Terriers. And for all outside studs, paperwork will be held on file, so that all parent information regarding our puppies can be made available on potential puppy owner requests.

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