50 Saber Tails Fall 2017
Petit Basset Griffon Vendéen Club of America
It has been two and a half years since the discovery by Dr. Catherine Mellersh and colleagues at the Animal Health Trust
of the gene mutation that leads to primary open angle glaucoma (POAG) in the PBGV. This breakthrough has already
had an enormous impact on our breed. At this time, it would be helpful to take a look back at the events leading up to
this discovery and consider the effect on future generations of PBGVs.
Glaucoma is traditionally thought of as a plumbing problem. The normal eye has cells that produce fluid and the drain-
age of this fluid from the eye must match its production in order to maintain normal pressure within the eye. When
drainage is blocked, the increased intraocular pressure damages the optic nerve and results in pain and impaired vision.
Sometimes the blocked drainage is due to a structural problem that reduces the rate of fluid outflow from the eye. This
is known as primary closed angle glaucoma, a condition that can be detected by a veterinary ophthalmologist using a
technique called gonioscopy.
PBGVs are not predisposed to the closed angle form of glau-
coma; instead, they develop the open angle form. Until 2015,
there was no way to foretell if your dog was going to develop
open angle glaucoma; instead, you discovered this when your
dog developed painful symptoms and went blind.
Twenty years ago, glaucoma didn’t seem to be a major problem
for the breed. In fact, it was barely on the radar screen. The 2000
health survey revealed that 16.4% of PBGV owners thought that
eye disease was a great concern for the breed, but that was not
due to glaucoma. Fifty-seven dogs out of 640 (8.9%) had persistent pupillary membranes while 17 (2.7%) had cataracts.
Only 4 of 640 dogs (0.6%) reported glaucoma; the same percentage reported lens luxation. The 2010 health survey
showed that 11.6% of our dogs had some eye problem, making eye problems the most common disease on the list.
Again, the most common problems were persistent pupillary membranes and cataracts. Glaucoma was reported in 4
dogs out of 302 (1.3%).
Glaucoma was present in the North American PBGV population but from health survey evidence it didn’t seem to be a
serious problem for our breed. We must keep in mind, however, that the numbers derived from a health survey are only
accurate if a representative cross-section of the population participates. Nevertheless, there were a few PBGV owners at
that time who insisted that the problem was worse than the health survey indicated. And we became aware that there
were clinicians and researchers who were interested in investigating POAG in PBGVs.
In 2012, glaucoma was a main topic at the 3rd BGV World Congress in the UK, which was attended by several PBGV-
CA members, including Helen and Charlie Ingher, Nick Frost, Jeff Pepper and Jan Zigich. We learned that Dr. Andreas
Komáromy (Michigan State University) was collecting PBGV DNA samples in collaboration with Dr. Catheryn Mellersh
(Animal Health Trust, UK), who had been successful in finding the POAG gene mutation in other dog breeds and had
turned her attention to the PBGV. Her work received incredible support from Vivien Phillips (BGV Club, UK) and Dr. Peter
Bedford (Veterinary Ophthalmologist, UK). The PBGVCA Health Committee arranged for Dr. Komáromy to present semi-
nars, examine eyes, and collect blood at the 2013 PBGVCA National in Houston, TX, and the 2014 National in Camp Hill,
PA. Throughout this time, we were hearing about more PBGVs developing glaucoma.
We rejoiced when, in 2015, Dr. Mellersh identified the gene defect leading to POAG in PBGVs. The mutation is in a gene
called ADAMTS17. This mouthful stands for A Disintegrin-like And Metalloprotease with ThromboSpondin type1 motif
POAG UPDATE
By Laura Liscum, Assistant Chair to the Health Committee
CLEAR
: Your dog inherited good genes with no
mutations from both parents. S/he will not develop
POAG and will not pass the disease to offspring.
CARRIER
: Your dog inherited a good POAG gene
from one parent, but a bad POAG gene from the other
parent. S/he will not develop POAG but can pass the
defective gene to offspring.
AFFECTED
: Your dog inherited bad POAG genes
from both parents. S/he will develop POAG and will
pass the defective gene to all offspring.