POODLE Update - EYE DISEASE RESEARCH Advancements Depend on Input from Breeders & Owners - Purina Pro Club
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POODLE Update
A NESTLÉ PURINA PUBLICATION DEDICATED TO POODLE ENTHUSIASTS VOLUME 18 | SPRING 2020
EYE DISEASE
RESEARCH
Advancements Depend on Input
from Breeders & Owners
SPRING 2020
RESEARCH OF POODLE EYE DISEASES
NEEDS SUPPORT FROM BREEDERS & OWNERS
Eye diseases in Poodles have ophthalmology at the University of
long been a health concern. When Pennsylvania School of Veterinary
Poodles joined the Canine Health Medicine, says, “Vision problems
Information Center (CHIC) program still affect far too many Poodles.
in 2004, eye examinations were Compounding efforts to identify
one of the initial requirements gene mutations, we have a short-
across all three varieties for CHIC age of DNA samples from all
certification. Despite efforts to varieties of Poodles. It takes a
encourage eye tests and advise commitment from breeders and
breeders to selectively breed owners working with researchers
against eye diseases, one expert to help advance discovery of
notes an ongoing steady increase causative gene mutations. Then,
in Poodle eye diseases. it’s up to breeders to selectively
Gustavo Aguirre, VMD, PhD, breed dogs that will not produce
professor of medical genetics and offspring with eye diseases.”
2
POODLE Update
PROGRESS REPORT ON MINIATURE & TOY POODLE EYE DISEASES
The Poodle Club of America Foundation is help- a less severe form of ONH or a totally different
ing to fund a six-year genetics study that began disorder.
in 2014 at the University of Pennsylvania. The “I feel that ONH and Mp are part of a continuum,”
research, led by Dr. Gustavo Aguirre, is focused Dr. Aguirre says, noting that the two conditions
on helping to advance understanding of optic often appear in the same Poodle pedigrees. “I
nerve hypoplasia/micropapilla and cataracts in speculate that ONH is a disease caused by genes
Miniature and Toy Poodles. at two separate loci, but that research needs to con-
Optic nerve hypoplasia (ONH) is a non-progressive tinue in order to prove or disprove the hypothesis.”
congenital defect causing blindness or severely Dr. Aguirre advises breeders not to breed dogs
impaired vision. Miniature Poodles have a high with ONH; however, he says there is not enough
prevalence, and a few cases have been reported information to preclude Poodles with Mp from
in Toy Poodles. Considered a rare genetic defect, being bred. For both eye diseases, puppies can
ONH affects one or both eyes and occurs when be examined as early as 6 to 8 weeks of age to
the optic nerve fails to develop normally. Disease identify the conditions before going to new homes.
severity is based on the extent of damage to the Breeders are encouraged to have eye examinations
optic nerve. of their litters.
Originating from the optic disc at the back of the Hereditary cataracts can be challenging because
eye, the optic nerve is made up of nerve fibers that they typically do not appear until a dog is around
connect retinal cells with visual centers in the brain. 4 to 5 years of age, oftentimes after already receiv-
The optic disc appears grayer and abnormally ing eye clearances from health testing. In Toy and
small in dogs with ONH due to fewer nerve fibers. Miniature Poodles, dogs are born with normal
This means that the brain receives fewer signals lenses that gradually lose their transparency.
for light reception. Cataracts can involve the nucleus, or central part,
In the ONH study, the researchers looked at of the lens, as well as the lens cortex, or more
the pedigrees of 43 Miniature Poodles, nine of peripheral layers. The rate and progression of
which were affected by ONH in both eyes. They cataracts vary.
found a possible common founder, though none “When older Poodles present with cataracts,
of the candidate genes tested correlated with there is no way to know if it is due to aging or
ONH. The study was published in the January heredity unless those dogs have records of pre-
2020 issue of Veterinary Ophthalmology. vious exams dating to their younger years,” Dr.
Meanwhile, Miniature Poodles also are suscep- Aguirre says. “We would like to search for the
tible to micropapilla (Mp), a condition similar to mutation in Poodles, but we need more samples.
ONH in which dogs have abnormally small optic Cataracts can be caused by other things, such
discs. Unlike ONH, Mp usually is not associated as progressive retinal atrophy, so we need more
with a visual defect, implying that Mp could be samples to account for these possibilities.”
A renowned eye disease re- In efforts to better understand Standard Poodles, as well as
searcher, Dr. Aguirre discovered the genetics and treatment options studies of optic nerve hypoplasia/
the mutation for the progressive for eye diseases, the Poodle Club micropapilla and cataracts in
rod-cone degeneration form of of America Foundation is helping Miniature and Toy Poodles. The
progressive retinal atrophy (prcd- to fund eye disease research. goal is to reduce the incidence
PRA) in Toy and Miniature Poodles Currently, the Foundation is of eye diseases in all varieties of
in 1998. DNA testing for prcd-PRA supporting genetic research of Poodle through education and
is a required test for CHIC certi- polymicrogyria and day blind- development of genetic tests.
fication for these varieties. ness/retinal degeneration in
3
SPRING 2020
open, she continued to find her
way around by smelling and
feeling.
Curtisy Briggs of Malvern,
Pennsylvania, adopted the
puppy in December 2002 at
10 weeks of age knowing she
was blind. “I named the puppy
‘Celie’ after the protagonist in
‘The Color Purple.’ I hoped that
the puppy would be strong and
overcome adversity like Celie
did,” she says.
The breeder had taken the
puppy to a veterinary ophthal-
mologist, who determined her
eyes were normal. The problem
appeared to be neurological and
have to do with visual processing
in the brain, though the cause
of blindness was a mystery.
“I noticed quickly that Celie was
not completely blind,” Briggs says.
“She seemed to see shapes and
followed my other dogs unerr-
ingly in a chase. I sometimes saw
her avoid obstacles in her path,
and she would sit and look into
the bright sunlight as though she
was watching the trees or sky. I
wondered if her eyes could see,
but her brain could not organize
the picture right.”
Unbeknownst to Briggs at the
time, Celie suffered from the
neurological condition polymi-
crogyria (PMG), which often but
not always affects vision. The
puppy’s eyes had normal vision.
Born with the neurological disease
polymicrogyria, “Celie,” a Standard
NEUROLOGICAL DISEASE The optic nerves that carry visual
Poodle, was visually impaired and PMG & VISION PROBLEMS signs to relay centers in the brain,
had partial complex seizures contrib- There was nothing unusual which control pupil reflexes, eye
uting to emotional and behavioral
problems. about the newborn black Stan- movement and some visual pro-
dard Poodle at first. Like her cessing, were normal, as were the
littermates, she felt and sniffed relay centers. The abnormality
her way around the whelping was at the visual cortex. All that
box. When their eyes began to Briggs knew was that Celie was
4
POODLE Update
on the leg. The Standard Poodle’s
POODLE OWNERS & BREEDERS CAN HELP behavior continued to worsen.
ADVANCE EYE DISEASE RESEARCH “Once I turned around to find
Celie a few yards away hunched
Breeders and owners of all varieties of Poodle are encouraged over and about to spring toward
to submit DNA from dogs affected with eye diseases, including me,” Briggs says. “For the first
polymicrogyria in Standard Poodles, to Dr. Gustavo Aguirre and time in my life, for a split second,
his team at the University of Pennsylvania. To submit samples, I was afraid of my own dog.”
please contact Dr. Aguirre’s lab at 215-898-9426 or by email at Briggs decided to take Celie
lmelnyk@vet.upenn.edu. to a Poodle eye clinic where Dr.
Researchers at the University of Missouri are seeking DNA Aguirre, whom she had consulted
samples of Standard Poodles diagnosed with polymicrogyria. about other Poodles, was going
“The more samples we have, the more powerful our studies will to perform eye examinations.
be and the more likely we will be to find an answer,” says Dr. Dennis Dr. Aguirre immediately diag-
O’Brien. “It is critical, however, that the diagnosis is confirmed nosed Celie’s problem as com-
by a veterinary neurologist, as there are other diseases that can ing from the brain, rather than
cause vision problems.” Please contact Dr. O’Brien at ObrienD@ being a vision problem, and told
missouri.edu to learn how to participate. Briggs he had seen a few Standard
Poodle puppies with a type of
basically blind and had somewhat nism, but sometimes the circling neurological blindness known as
odd behavior. became frantic and she refused polymicrogyria. He had written an
Located near the rear of the to listen or be caught. “It was article describing four affected
outside surface of the brain, the almost as though she was in the dogs that was published in 1994 in
visual cortex processes visual grip of some urgent force com- Progressive Veterinary Neurology.
signals into recognizable objects. pelling her to ignore everything “The first affected dog I saw was
The brain’s surface, or cortex, is around her,” Briggs says. a white male Standard Poodle,”
normally covered in large folds The obsessive circling pro- Dr. Aguirre says. “The dog had
called gyri. However, in dogs gressed, and Celie was not able bizarre visual behavior. He could
with PMG, the cortex has many to stop herself as she ran to not see, but he also was not
excessive small folds, or gyri, near collapse. Briggs stopped totally blind.”
that disrupt normal connections playing in the yard with Celie Dr. Aguirre has since examined
within the cortex. because any excitement seemed quite a few Standard Poodles
Functioning of the temporal to bring on the rampant circling. with PMG and described a range
cortex, located in front of the She referred to this as Celie’s of phenotypes. “Some dogs are
visual cortex, may be severely “fugue state,” a condition in which able to see more than others,” he
affected as well. The temporal she seemed unaware of her sur- says. “Most, but not all, have a
cortex is involved in emotional roundings and often slammed form of hydrocephalus, or fluid
responses, which is why some into things she normally avoided. buildup in the cavities deep within
dogs with PMG have personality Briggs observed that Celie the brain. We see one to two cases
issues and seizures. sometimes smacked her lips and a year. There are undoubtedly
Celie was exceptionally affec- slightly shook her head in situ- more cases, though most affect-
tionate and craved closeness with ations that made her nervous. ed dogs are likely euthanized as
Briggs when they were together Calming medication helped for puppies. It also is likely that dogs
in the house, but outside in the about one year but eventually that are mildly affected are just
yard was another story. Celie became ineffective. One day when not diagnosed unless a magnetic
often ran in circles, which Briggs Celie was almost 5 years old, she resonance imaging (MRI) study
thought was an orienting mecha- lunged at Briggs biting her hard is done.”
5
SPRING 2020 Believing that Celie had PMG, have motor problems, and not have been diagnosed. “As I did Dr. Aguirre referred Briggs to a all have behavior or emotional with Celie, owners may struggle veterinary neurologist at the problems or seizures. Many of for years without knowing what University of Pennsylvania, who these dogs with PMG are likely the problem is,” Briggs says. confirmed the diagnosis based on going undiagnosed.” Describing the genetic work MRI. The specialist also diagnosed Veterinary neurologist Dennis at the University of Missouri, Celie as having partial complex O’Brien, DVM, PhD, the Chancellor’s Dr. O’Brien says, “The initial gene motor seizures, which accounted Chair in Comparative Neurology mapping study in Dr. Gary for the unusual behaviors of circling, at the University of Missouri Johnson’s lab found a locus lip smacking and head shaking. College of Veterinary Medicine, more common in affected dogs Ironically, the calming medication than in the population at large. that Celie took lowered her thresh- This locus has been difficult to old for seizures. She had to be work with, but we have investi- weaned off the medication, as every gated that area extensively as seizure caused more brain damage. well as performed searches of Without the medication, Celie was whole genome sequences we’ve increasingly wild, and she had begun acquired. We have not found the spinning around the house too. culprit yet. We hope to someday “I knew Celie had to be suffering make PMG a disease of the past.” in ways I could not even fathom and that my other dogs were DAY BLINDNESS/RETINAL paying a price for living with her DEGENERATION IN erratic behavior,” Briggs says. STANDARDS When Celie was almost 5 years In 2013, Wendy Grogan of old, she was the oldest dog known Hackettstown, New Jersey, had to have PMG. Unfortunately, the a litter of five Standard Poodle disease ultimately won, and Briggs puppies — one white female made the difficult decision to have and four black males. She de- her euthanized. At least there was has been studying PMG since cided to keep the white female. solace for Briggs knowing that 2007. He knows firsthand the It soon became apparent that Celie had brought attention to challenges of living with a dog the Poodle she named “Sugar” the disease and that her DNA had with the disorder. “Oliver,” a white walked into everything in her gone to genetic research. male Standard Poodle, came to path when she was outside, yet “It is so important to get a live with him in 2008 after being she was fine in the house. genetic test because breeders diagnosed with PMG. “My son said, ‘She’s either very are producing affected puppies Unfortunately, Oliver, who was stupid or blind,’” Grogan says. “I that they attribute to bad luck,” more severely affected than Celie, knew she wasn’t stupid. I watched Briggs says. “They euthanize lived with Dr. O’Brien a short time. her carefully for the next week, affected puppies and then repeat “He was a sweet dog, but it was and then I emailed Dr. Aguirre the breeding, producing more tough for him to manage with whom I knew from helping my affected dogs. Without a test, poor vision,” he says. “He was mother bring dogs to his eye there is no way to know which getting injured too frequently, clinics. I told him that it almost puppies are affected with the so I made the decision to eutha- seemed like she was blind but specific disease. Since abnormal- nize him.” only when she went outside.” ities vary so much, PMG can be Since Celie’s case, more Stan- Dr. Aguirre told Grogan he had overlooked as a cause. Not all dard Poodles, some even older examined another Standard dogs with PMG are blind, not all than Celie with less severe PMG, Poodle, coincidentally named 6
POODLE Update
“Sugar,” in the 1980s who was Thus far, DB/RD has only been
one of three puppies in a litter reported in Poodles. It is a pro-
of five having difficulty seeing in gressive condition that affects
bright light. “It is rare for dogs to the cone and rod retinal receptors,
have difficulty seeing in just bright rendering some though not all
light,” Dr. Aguirre explains. “It is Poodles totally blind initially. “It
more common when there are is a variable disorder,” Dr. Aguirre
retinal problems for dogs to have explains. “Some affected dogs at
trouble seeing in dim light, indicat- 2 years of age are indistinguish-
ing problems with the rod retinal able from dogs with end-stage
receptors. When bright light is a progressive retinal atrophy, yet LOOKING TO REPRINT?
problem, it means there are in other dogs the retina remains
problems with the cone retinal clinically intact for several years.” Poodle Update articles may be
receptors.” Sugar was adopted at 4 months reprinted provided the article
Dr. Aguirre did not hear of of age by a veterinary technician, is used in its entirety and in a
another case until early 2000 Cristie Nielsen of Oceanport, New positive manner. To request
when he began examining other Jersey, who knew about the vision permission to reprint this article,
Standard Poodles with day blind- problem and hoped a treatment please contact the editor at:
ness. When he learned about would become available. Unfor- Barbara.Fawver@purina.nestle.
Grogan’s Sugar, it was an oppor- tunately, Sugar’s vision worsened. com. Reprints should include
tunity to study the family. Examin- “When Sugar was about 1 year the following attribution:
ing the littermates, sire and dam, old, I noticed that she had started Used with permission from the
he found only Sugar was affected. bumping into things indoors,” Poodle Update, Nestlé Purina
When the first Sugar was Nielsen says. Despite being PetCare.
diagnosed, an electroretino- virtually blind, Sugar, now 6
gram (ERG) was used to record years old, romps with Nielsen’s
the retina’s electrical response male Miniature Poodle, goes for
to light or a veterinary oph- walks and leads a full life.
thalmologist would check the Vision problems like day
retina of the eye after it had blindness/retinal degeneration
been removed. Today, optical and PMG vary considerably
coherence tomography (OCT) among individual Poodles. The
provides a high-resolution method good news is that with help from
of examining anatomically a dog’s researchers and diligent breeders
retina, though a dog must be who regularly health test their
anesthetized for the procedure. breeding stock, some of the
Meanwhile, analysis of the DNA hereditary eye diseases may one
of Sugar and her relatives allowed day no longer be a problem. n
Dr. Aguirre and Karina Guziewicz,
PhD, research assistant professor
Purina thanks Pat Forsyth,
of ophthalmology, to identify the vice president of the Poodle
gene mutation. Subsequently, a DNA Club of America Foundation
test was developed for Poodle board of directors, for helping
day blindness/retinal degenera- us to identify this topic for the
tion (DB/RD). The test is available Poodle Update.
from the diagnostic testing lab
Wisdom Health, formerly Optigen.
7
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