Canine Top 5 Genetic Diseases Flashcards
what dog breeds are affected by von willebrand’s?
dobermans, german shepherds, goldens, standard poodles, pembroke welsh corgis, mini schnauzers, shetland sheepdogs, basset hounds, & scottish terriers
what is the classical clinical presentation of a von willebrand’s dog?
excessive bleeding/brusing after venipuncture or surgery, epistaxis, gingival bleeding, & hematuria
what is the most common type of von willebrand’s?
type 1
what are the 3 types of von willebrand’s?
type I - produces a truncated form of VWF with mild to moderate signs, type 2 - intermediate form with low VWF seen in GSP & GWP, type 3 - rarest & most severe where there is a total absence of VWF seen in shetland sheepdogs & scottish terriers
how is von willebrand’s diagnosed?
measuring a low VWF concentration, genetic testing, platelet numbers, APTT & PT are normal
how is von willebrand’s treated?
cryoprecipitate/fresh plasma/fresh whole blood, desmopressin to mobilize high-molecular-weight hemostatic multimers from endothelial granules
what is von willebrand’s? why is it important?
factor VII related antigen that assists in the first step of clot formation by facilitating platelet adhesion
what is the most common genetic inheritance of von willebrand’s?
autosomal dominant with incomplete penetrance - autosomal recessive is rare
what drug may worsen VWF disease?
levothyroxine
what dog breeds are commonly affected with ivermectin toxicity?
collie, border collie, longhaired whippets, GSD, & shetland sheepdogs
what clinical signs are seen in dogs with ivermectin toxicity?
mydriasis, ataxia, tremors, & coma
how much ivermectin results in toxicity in dogs with the genetic mutation?
treatment with greater than 120 mcg/kg
how is ivermectin toxicity diagnosed?
history of ivermectin administration is susceptible breeds & genetic testing
what other drugs are dogs with ivermectin toxicity also susceptible to having reactions? why?
loperamide, vincristine, doxorubicin, milbemycin - mutations of the MDR1 gene associated with the ability of drugs to cross the into the CNS
what is the gene that causes degenerative myelopathy?
SOD1 gene mutation
what dog breeds are usually affected by degenerative myelopathy?
middle aged to older GSD, pembroke welsh corgis, boxers, rhodesian ridgebacks
what is the classic case presentation of a dog with degenerative myelopathy?
slowly progressive ataxia over months with loss of pelvic limb conscious proprioception that may progress to the thoracic limbs in late disease, paraparesis, but NONPAINFUL
how is degenerative myelopathy diagnosed?
genetic testing & MRI/CSF tap to rule out other causes of paraparesis
how is degenerative myelopathy treated?
supportive care - ambulatory aids (slings, carts), & well-padded bedding
T/F: anti-inflammatories are of no benefit for dogs with degenerative myelopathy
TRUE
what does the SOD1 gene encode for?
superoxide dismutase
what breeds are predisposed to DCM?
dobermans, boxers, great dane, labs, newfoundlands, st bernards, GSD, & irish wolfhounds
what is the classic case presentation of a dog with DCM?
sycope/sudden death, tachypnea, dyspnea, weakness, & exercise intolerance
how is DCM diagnosed?
thoracic rads, echo is the gold standard, ECG with PVC, v tach, & atrial fibrillation - genetic testing available in dobermans
how is DCM treated?
diuretics, pimobendan, ace inhibitors
T/F: 60% of dobermans with both autosomal mutations will develop DCM
TRUE
what is the PDK4 gene mutation in dobermans related to DCM?
gene codes for pyruvate dehydrogenase kinase 4 a mitochondrial enzyme that is required for production of ATP, increases the likelihood of DCM by 10X
what is the NCSU DCM2 gene mutation in dobermans related to DCM?
increases the likelihood of DCM by 21X
what is the photoreceptor type of progressive retinal atrophy?
begins during the first year of life - seen in irish setters, collies, norwegian elkhounds, mini schnauzers, & belgian sheepdogs
what is the photoreceptor degeneration type of progressive retinal atrophy?
develops at 3-5 years old seen in mini/toy poodles, cocker spaniels, labs, papillons, springer spaniels, & akitas
what is the late onset type of progressive retinal atrophy?
develops around 10 years of age - seen in gordon setters, irish setters, australian cattle dogs, & tibetan terriers
what is the first sign usually seen with progressive retinal atrophy? how does it progress?
night blindness that progresses to complete blindness over months to years - can end with the late development of cortical cataracts in certain breeds
what is seen on ophthalmoscopic exam that supports the diagnosis of progressive retinal atrophy?
increased tapetal reflectivity, decreased pigmentation of nontapetal fundus, attenuated & decreased retinal vessels, & atrophied optic papillae
how is progressive retinal atrophy diagnosed?
ophthalmoscopic exam, electroretinography, & genetic testing
how is progressive retinal atrophy treated?
no treatment
how many genetic mutations have been shown to be causal for progressive retinal atrophy?
14
T/F: most mutations are autosomal recessive for progressive retinal atrophy
TRUE
what is the PDE6A frame-shift mutation causing progressive retinal atrophy?
rode cone dysplasia seen in 8-12 week old cardigan welsh corgis
what is the PDE6B frame-shift mutation causing progressive retinal atrophy?
rode cone dysplasias, sloughi dogs & irish setters 2-3 years old
what is the PRCD mutation causing progressive retinal atrophy?
progressive rod-cone degeneration seen in multiple breeds
what is the CNGB1 mutation causing progressive retinal atrophy?
progressive retinal atrophy seen in papillons
what is the TTC8 mutation causing progressive retinal atrophy?
seen in goldens & labs
what is the C17H2orf71 mutation causing progressive retinal atrophy?
rod-cone degeneration seen in gordon setters, irish setters, & tibetan terriers at 10 years old
what is the RPGR mutation causing progressive retinal atrophy?
x-linked progressive retinal atrophy seen in huskies & samoyed 3-5 years old
what is the RHO mutation causing progressive retinal atrophy?
autosomal dominant progressive retinal atrophy seen in 4 month old english & bull mastiffs
