▁common ▁in ▁drop - eared ▁bre eds ▁of ▁dog , ▁including ▁the ▁American ▁C ocker , ▁and ▁lux ating ▁pat ell as ▁and ▁hip ▁d ys pl asia ▁have ▁been ▁identified ▁in ▁some ▁members ▁of ▁the ▁bre ed . ▁ ▁Heart ▁conditions ▁such ▁as ▁dil ated ▁card iom y op ath y , ▁where ▁the ▁heart ▁becomes ▁weak ened ▁and ▁en larg ed , ▁and ▁sick ▁sin us ▁synd rome , ▁which ▁is ▁a ▁type ▁of ▁ab normal ▁heart ▁be ating ▁which ▁causes ▁low ▁blood ▁pressure , ▁have ▁been ▁identified ▁in ▁the ▁bre ed . ▁Ph osph of ruct ok in ase ▁def ic iency ▁is ▁a ▁condition ▁caused ▁by ▁a ▁re cess ive ▁gene ▁in ▁the ▁bre ed ▁which ▁prevents ▁the ▁met abol ism ▁of ▁gl uc ose ▁into ▁energy , ▁causing ▁the ▁dog ▁to ▁have ▁extremely ▁low ▁energy ▁and ▁be ▁unable ▁to ▁exercise . ▁The ▁gene ▁which ▁causes ▁this ▁appears ▁in ▁around ▁ 1 0 ▁percent ▁of ▁the ▁population , ▁but ▁DNA ▁testing ▁can ▁prevent ▁two ▁car rier ▁dogs ▁from ▁bre eding ▁and ▁thus ▁creating ▁pu pp ies ▁with ▁this ▁condition . ▁ ▁American ▁C ock ers ▁are ▁also ▁pr one ▁to ▁can ine ▁ep ile ps y ▁and ▁the ▁related ▁condition ▁known ▁as ▁R age ▁Sy nd rome . ▁The ▁latter ▁is ▁a ▁form ▁of ▁ep ile ps y ▁which ▁can ▁cause ▁a ▁normally ▁pla cid ▁dog ▁to ▁eng age ▁in ▁sudden ▁and ▁un prov oked ▁violent ▁attacks . ▁Initial ▁research ▁shows ▁that ▁both ▁conditions ▁appear ▁to ▁be ▁inher itable