To skip
the SAS overview, click one of the below links.
For Dr Stern's SAS study submission information click HERE
For an explanation of SAS diagnosis by "velocity" only (no SAS defect
on
echo) click HERE
For
Darla's diet information click HERE
For Breeding
Recommendations click HERE
ABOUT SUBAORTIC STENOSIS IN ROTTWEILERS
Sub Aortic Stenosis (SAS) is the
most
common congenital heart defect in Rottweilers.
Rottweilers
are affected with SAS on all continents and almost all bloodlines.
Many of the presumed heat stroke or poisoning deaths are later found
(if a necropsy is done) to have been SAS deaths.
SAS
involves the narrowing of the out-flow tract from the left ventricle
leading to the aorta. When there is a narrowing of the
tract, the heart must pump harder to get blood through the smaller
opening. As the SAS-affected dog matures, his/her heart develops a
thicker muscle to push harder, which (in
moderate to severly affected dogs) leads to an irregular heart
beat, a lack of blood to the heart, congestive heart failure, or sudden
death.
SAS is diagnosed in living dogs by a cardiologist performing a
dopplar echocardiograph exam of dogs. Severe
cases can often be tentatively diagnosed by auscultation.
Practitioner exams even if by echo are NOT definitive!
Note that sedation or anesthesia is detrimental to accurate evaluation.
Additionally SAS can be diagnosed by a cardiologist based upon
narrowing, a ridge, velocity or all three. You dont need all three to
be diagnosed with SAS, some dogs only have ONE at the time of
evaluation.
Research
is indicating that
the mode of heritability can vary by breed, and originate at different
gene locations. For example Newfoundand SAS is a totally different gene
location than Golden Retrievers and Rottweilers, and Newfoundlands NOW
have a
DNA test!
NEWS
Rottweiler friends this is going to be long but please read.
Sas update from Dr Sterns
Sas is “looking” to be recessive in Rottweilers , Bullmastiffs and
Goldens
Yes, recessive
Here’s my notes from a follow up conversation with Dr Stern
1- pattern of inheritance really does not matter until we have DNA test.
Any dog that is part of a pair that produces one should be assumed part
of the process (recessive or dominant variable penetrance)
2- vet cardiologist are not all using most modern equipment or
techniques. So not all are equal. The newer OFA advanced cardiac form helps
but not totally
3- velocities
- *If lvot reading is taken subcostal (under ribs with the probe pointing forward )
then anything under 2.0 m/s is acceptable.
*If lvot reading is not taken subcostal (below ribs) then lower levels.
*Lvot taken subcostal (under ribs) will only rarely be under 1.7
(I’m not changing my personal velocity criteria (under 1.7) but
I’m giving you this info)
4- in some pedigrees if recessive but common it can appear as if dominant
even if it’s not.
His exact words “Remember that if the gene is common in the carrier
state, then a recessive disease can look dominant in some pedigrees”
5- yes there can be two types of SAS like in newfoundlands. No guarantee that what they’ve
seen for SAS in Rottweilers is the only type in the breed, but all he’s seen in his samples indicate
a single recessive type is most likely
6- continue to echo ALL breeding dogs until a DNA test comes out
AND try to make sure the lvot is taken subcostal (below ribs) In these cases
(readings were taken subcostal)all dogs under 2.0 m/s can be used but if they produce sas realize they
likely carry it and change your plans for those dogs
7- if lvot is not subcostal or you don’t know, then 1.7 and below is a reasonable
safe goal. Since you are unlikely to know how a dog was echo'ed I would personally maintain THIS CRITERIA!
8- when planning breedings, keep the fact that sas is likely recessive
in mind
*do a pedigree analysis and research, looking for affected dogs
,
*patterns (some popular dogs clearly throw lots of sas),
*use only
echoed breeding dogs
* consider all dogs that throw sas as a probable carrier
9- continue to submit samples to the study and hope the DNA market for
testing is found soon
To submit a sample contact lab at link lower down on this page
Read the full published study article here https://www.frontiersin.org/articles/10.3389/fvets.2019.00052/full?fbclid=IwAR0yRMtSZa-A8OyacOEt980MoO6OeIafoCX1xs12ajkt0Jslf9dPOpMGOtk
Also
read the Rottweiler Health Foundation post 3/2/19
An update on SAS research grant.
RESEARCH PROGRESS REPORT SUMMARY
Grant 02520-MOU: Identification of Genetic Markers for Familial
Subvalvular Aortic Stenosis in
Rottweilers
Principal Investigator: Research Institution: Grant Amount:
Start Date: 2/1/2018 Progress Report:
Report Due: 1/31/2019
Joshua Stern, DVM, PhD University of California, Davis $44,320.00
End Date: 1/31/2020 End-Year 1
Report Received: 2/15/2019
(The content of this report is not confidential and may be used in
communications with your organization.)
Original Project Description:
Subvalvular Aortic Stenosis (SAS) is a heart defect characterized by a
fibrous ridge located below the aortic valve. Affected dogs are at risk
of developing heart valve infections, congestive heart failure or
sudden death. Severely affected dogs have an average lifespan of 19
months. SAS is an inherited heart problem reported in Rottweilers. The
goal of this research is to identify causative genetic mutations and
develop a reliable genetic test for this condition in Rottweilers, to
aid breeders in making informed decisions to reduce the prevalence of
this condition. Once a chromosomal region of interest is identified via
a genome wide association study (GWAS), whole genome sequencing (WGS)
will be employed to identify variants associated with SAS. The top
variants identified via WGS will be submitted for Sequenom analysis to
prioritize variant pursuit.
Funding for the research is provided through the collaborative efforts
and generosity of the Rottweiler Health Foundation. The AKC Canine
Health Foundation supports the funding of this effort and will oversee
grant administration and scientific progress reports.
Publications:
Ontiveros, E. S., Fousse, S. L., Crofton, A. E., Hodge, T. E.,
Gunther-Harrington, C. T., Visser, L. C., & Stern, J. A. (2019).
Congenital Cardiac Outflow Tract Abnormalities in Dogs: Prevalence and
Pattern of Inheritance From 2008 to 2017. Frontiers in Veterinary
Science, 6. (Same link as I posted above)
Presentations:
Poster: Identification of genetic markers for familial subvalvular
aortic stenosis in Rottweilers. Conference: The 2018 National
Veterinary Scholars Symposium
Report to Grant Sponsor from Investigator:
Subvalvular aortic stenosis (SAS) is one of the most common inherited
heart problems reported in Rottweilers. For this study we aim to report
the top variant(s) associated with SAS in this breed. We recently
published a manuscript and determined that the prevalence of SAS in
Rottweilers is 1.17%. (Diane Richardson comment-this is among submitted
samples, I believe the actual incidence in real world is far higher)
We also have completed the first aim of this study, and pedigree
analysis results for the Rottweiler breed has been publish in Frontiers
Veterinary Journal. A genome-wide association study analysis was also
completed, and the region of association has been identified. We are
currently waiting to receive whole-genome sequencing results to proceed
with bioinformatic analysis. We are continuing to recruit affected and
control Rottweiler samples for Sequenom variant segregation analysis.
These are the single hardest "grades" or
"diagnosis" to accept.
To have your dog graded as Equivocal or worse,
affected with mild SAS
and yet the cardiologist tells you the heart looked and sounded perfect
on echo, with perhaps very slight aortic insufficency, aortic regurge,
turbulance etc.
and that your dog would have PASSED a simple auscultation exam. So you
get a grade you never expected. HOW can this be you want to know?!
The facts are simply that the
equipment we
currently
have is not
sensitive enough to image all the tiny defects, BUT research and
necropsies HAVE proven that these elevated velocities- especially when
accompanied by aortic insufficiency, aortic regurge, turbulance etc-
really are extremely
slight affected dogs.
IF you were to open your dog's heart up, you would
be able to see the
miniscule defects (and in a test breeding Newfoundland study they did
just that, sacrificed some of the animals produced and examined the
hearts).
THIS is why I am such a STRONG advocate of breeding
Rottweilers (and
preferably all Rottweilers having heart certifications done) being
echoed BECAUSE auscultations can and do MISS mild and equivocal
affected dogs!!!
Dr J. Stern has agreed to create a short document
about this for me at
a future date but for now his short quote sums up the above facts:
"a
device that images from outside the heart could never be as accurate as
looking directly at the inside of the heart. As such, The
presence of a subvalvular ridge on echo is not a requirement for
diagnosis of mild or equivocal SAS. Simply the velocity has been
used by cardiologists for years."
Dr K. Meurs & Dr J. Stern have conducted U.S.
studies for the
Golden
Retrievers,
Newfoundlands and Boxer breeds. Dr Meurs conducted a very limited
retrospective pedigree study for
Rottweilers through the RHF (Rottweiler Health Foundation) but this
study was hampered by a serious LACK of participants. Since I receive
calls and emails monthly from owners of afflicted dogs I KNOW this was
not caused by a lack of incidence of SAS in our breed. Instead the lack
of participation is directly linked to the number of breeders/owners
who
decline to participate!
Dr Stern is
currently collecting blood samples
from both
affected
(as
diagnosed by Cardiologist echo) and cardiologist echo clear dogs (proof
of
clear being an OFA certificate showing the C-ECHO suffix or a
cardiologist report) and they have
began a DNA evaluation of these samples
Preliminary findings are
that the gene(s)
is/are probably
similar as that which afflicts Golden Retrievers (but not the SAME one)
and the
likely on just a single chromosome.
A DNA test for this is
highly likely, IF
steady funding of the
research happens.
The Newfoundland breed got their test because of
steady, generous funding AND participation. One Newfoundland study had
6,000 dogs participating! Rottweiler people are FAR less likely to
donate samples or money.
Rottweiler Familial Subaortic Stenosis
Study
They are currently
STILL looking
for DNA samples
from
Rottweilers with
a diagnosis of Subvalvular aortic stenosis (diagnosed by Doppler
echocardiogram) or proven clear of Subvalvular aortic stenosis (as
cleared by a cardiologist echo ) to advance their study to
identify a gene for the disease.
click image for full size
Please
return
THIS form with your sample and
documentation/reports and mail to:
Darla's
Diet