mutationmeansthat

heartmusclesdon’thaveenoughenergytoworkproperly.
Unfortunately,thisfindingwillnothelptheDobermansin
Europe,sinceitisthoughtthattheUnitedStatesand
EuropeanDobermanshavedifferentgenedefects.

Incontrast,DCMinGreatDanesisanX-linkedrecessive

trait.Withthismodeofinheritance,femalesthatinherit
onediseasegenearesilentcarriersofthedisease.Whena
femalecarrierhaspuppies,hermaleoffspringhavea50
percentchanceofbeingaffected!Affectedfemalesonlyarise
whenanaffectedmaleisbredtoacarrierfemale.

Whenadoghasadisease-causingmutation,thatdoesn’t

alwaysmeanthatthedogwilldevelopsymptomsofthe
disease.Thisfeatureofageneticdiseaseiscalledpenetrance.
Forexample,arrhythmogenicrightventricularcardiomy-
opathyisanautosomaldominantheartdiseasethatprimarily
affectsBoxers.Thegenedefecthasbeenidentifiedanda
genetictestisavailable.However,30percentofBoxerswith
thegenedefectneverdevelopdisease.Perhapstheyare
protectedbyothergeneticfactors,theenvironment,diet
oractivities.Ifthegenetictestindicatesthatadoghas
onecopyofthegenemutation,thatdogwillbeclinically
normalbutcanstillpassonthegenedefect.Therefore,the
dogshouldbebredonlytodogsthathavenomutation.If
thegenetictestindicatesthatadoghastwocopiesofthe
genemutation,thatdogshouldbeclinicallyevaluatedevery
yearandonlybredifitisanexceptionaldog.Theseexamples
remindusthathavingagenetictestforacaninedisease
doesnotalwaysleadtoastraightforwardpathforeliminating
thediseasefromthebreed.

Cataracttherapeutics.Cataractsarethemostcommon

causeofblindnessinhumansanddogs.Theycanbecaused
bytheagingprocess,exposuretoultravioletrays,oxidative
stress,metabolicdisordersorgeneticfactors.Indogs,there
isnobreedpredilectionforcataractformation.Theonly
treatmentoptionissurgerytoremovethecataractouslens
andimplantanewintraocularlens.

HeatherChandler,PhD,isanAssistantProfessorinthe

OhioStateUniversityCollegeofOptometry.Sheisstudying

acommoncomplicationofcataractsurgerycalledposterior
capsuleopacification(PCO).Thisoccurswhensomeofthe
cataractmaterialisleftbehindaftersurgery.Thesecellsgrow
andobscurevisionthroughthenewlens.Thishappensin
30to50percentofadulthumanswhohaveanintraocular
lensandin80-100percentofdogs.HumanswithPCOare
treatedwithalaserbeamtodestroythegrowingcells.This
treatmentisveryexpensiveandnotverysuccessfulindogs.

ThePBGVHealth&RescueFoundationfundedDr.

Chandler’sAKCCanineHealthFoundationgranttotesta
newtherapeuticstrategy.Shehasfoundapharmacological
agent,calledcyclosporine,thatkillsthecataractcellsthat
aregrowingback.Fortunately,thecyclosporinedoesnot
harmtherestoftheeye.Thesetestsareperformedincanine
eyesthathavebeenremovedforotherreasons.Dr.Chandler
isnowinvestigatinghowtodeliverycyclosporinetocanine
patientsandwhetherlong-termadministrationofthedrug
hasanyharmfuleffects.

Bloatandmultipleorganfailure.Bloat,alsoknown

asgastricdilatationvolvulus,referstodistensionofthe
stomachbygasandfluidfollowedbyrotationofthe
distendedstomachonitslongaxis.Therotationpinchesoff
thestomachandpreventsthegasandfluidfromescaping.
Stomachtissuecandieduetothelossofbloodcirculation.
Furthermore,thetwistingcancausehemorrhaging.Large
breeddogswithdeepchestsaremoresusceptibletobloat,
butthislife-threateningemergencycanoccurinanydog.

ElizabethRozanski,DVM,AssociateProfessorofClinical

SciencesatTuftsCummingsSchoolofVeterinaryMedicine,
describedhowbloattreatmenthasevolved.Fiftyyearsago,
mostdogsdidn’tsurvivebloat.Thischangedwhenitwas
realizedthatimmediatesurgeryisnecessarytocorrectthe
twistedstomachandremovedeadtissue.Today,bloatisa
survivabledisease.Aretrospectivestudyof498dogspresent-
ingatTuftsforsuspectedbloatrevealedthat24percentof
dogswereeuthanizedattimeofdiagnosis.Oftreateddogs,
84percentsurvived.Giventhehighrateofsuccess,whyare
somanyaffecteddogseuthanized?Amajorfactoriscostof
treatment,whichcanrangefrom$2,000to$8,000.

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