Genetic Diseases


All breeds suf­fer from some genetic dis­eases and Bull Ter­ri­ers are no excep­tion. Dis­eases that affect the Bull Ter­rier breed are:

  • Deaf­ness (Uni­lat­eral & Bilateral)
  • Heart Dis­ease
  • Kid­ney Dis­ease (hered­i­tary and PKD)
  • Lux­at­ing Patella

All the respon­si­ble breed­ers must test their ani­mals before breed­ing and all the respon­si­ble own­ers to be must ask for these tests before tak­ing a puppy. This is the road to a health­ier bull ter­rier breed !!!


From the first days of the breed Bull Ter­ri­ers has been rec­og­nized to have deaf­ness issues. For many years it was believed that only the white ani­mals could be deaf but this is not true because nowa­days we know that there are also some coloured ani­mals that was found deaf! Breed­ers had stopped breed­ing from ani­mals that were deaf in order to face this prob­lem but there were still some pup­pies born deaf and the rea­son for that is that until recently it wasn’t pos­si­ble to accu­rately iden­tify ani­mals which are par­tially deaf, and that breed­ers may have inad­ver­tently been breed­ing from ani­mals with less than per­fect hear­ing. Nowa­days it is pos­si­ble to test Bull Ter­ri­ers elec­tron­i­cally, to iden­tify exactly how well the ani­mal can hear. This test, known as the B.A.E.R. (Brain Audi­tory Evoked Response) Test, can car­ried out from about 5 weeks old and it’s a quite sim­ple and easy process. There are three deaf­ness classifications:

  • Nor­mal bilat­eral hearing
  • Uni­lat­eral deaf (deaf in one ear)
  • Bilat­er­ally deaf­ness (deaf in both ears)

Only the ani­mals with nor­mal bilat­eral hear­ing should be bred, to try and erad­i­cate this gene from the breed­ing stock.


Bull Ter­ri­ers are affected mostly by Mitral Dys­pla­sia and Subaor­tic Steno­sis. The affected ani­mals can suf­fer from heart attacks whilst other sign may be lack of activ­ity or short­ness of breath. A vet­eri­nary car­di­ol­o­gist can detect heart mur­murs that come with those dis­eases with stetho­scope aus­cul­ta­tion. There are also some tests you can do in order to check heart’s health which include x-ray of the chest, elec­tro­car­dio­graph to mea­sure the heart’s elec­tri­cal activ­ity and a color Doppler test.


There seem to be two types of kid­ney dis­eases in Bull Ter­ri­ers. The first one is Poly­cys­tic Kid­ney Dis­ease (PKD) and the sec­ond one is hered­i­tary Nephritis.

Typ­i­cal signs of kid­ney fail­ure include the following:

  • poor appetite
  • dull­ness or lethargy
  • weight loss or stunted growth
  • poor hair coat
  • vomiting/diarrhea
  • foul breath and mouth ulcers
  • mus­cle twitch­ing and convulsions
  • drink­ing excess water and pass­ing too much urine
  • pale gums (anemia)
  • dehy­dra­tion (sticky dry gums)

In order to diag­nose these dis­eases you can do a kid­ney ultra­sound or a biopsy but the most com­mon and easy way is a blood test to deter­mine the Urine Pro­tein Cre­a­ti­nine ratio (UP/C). In most breeds a read­ing of up 1.0 is nor­mal how­ever the rec­om­men­da­tion for the Bull Ter­rier is that must not be /higher than 0.3.


The patella is a small bone slid­ing in a groove in the sti­fle joint — equiv­a­lent to the kneecap in the human knee. If the groove is too shal­low the patella may slip side­ways out of the groove, caus­ing the dog to limp, until it slips back — often seen as a limp, a skip and hop fol­lowed by nor­mal move­ment. The patella may slip out of its groove eas­ily or only occa­sion­ally. In a badly affected dog the joint is painful and becomes arthritic. The mode of inher­i­tance is poly­genic (con­trolled by sev­eral or many genes) and can only be com­bated by breed­ing from unaf­fected par­ents. A vet­eri­nary sur­geon can test the joint by feel­ing how firmly seated the patella is in its groove and by a sim­ple x-ray.
It is wise to limit your puppy/adolescent Bull Terrier’s activ­ity (i.e. don’t allow them to jump from heights, etc.) to help reduce undue strain on young joints, for the first six months. It is advis­able that all breed­ing stock should be tested for this inher­ited prob­lem and any dog found to have the dis­ease, should be removed from any breed­ing program. 

!The above diseases are officially the main category of genetic diseases of the Bull Terrier breed. But there are some others, such as Lethal Acrodermatitis, known as LAD, a deadly skin disease first described in 1986. It has found that dogs diagnosed with acrodermatitis have been found to have low levels of zinc. In human intestinal acrodermatitis, taking zinc helps a lot but unfortunately this does not happen in dogs. This condition is manifested by skin lesions on the legs and muzzle (mainly), diarrhea, bronchopneumonia, growth retardation and immunodeficiency. The first signs of the disease appear in the first weeks of the puppy’s life. Puppies with acrodermatitis have a characteristic cachectic look from the beginning of their life. As the disease progresses, hyperkeratosis of the feet and deformity of the nails are observed. Due to immunodeficiency, dogs often suffer from skin infections such as Malassezia or Candida. Other symptoms include severe thinning of the hair and hard palate, to which food debris sticks, causing health issue and bad breath. Puppies with acrodermatitis can’t live more than 7 months. Dogs that can survive a little longer suffer from serious health problems. Luckily, in recent years a way has been found to examine the animals before put them in breeding with a DNA test, in order to avoid breeding affected puppies. It is obvious that some dogs may be carriers of the disease without ever having manifested it, but they can carry it to their offspring. The MKLN1 gene test is the way to know if a dog is a carrier of the disease or not.



With love and pas­sion for breed­ing try­ing to pro­tect the health,

Labrini Maniati — Kostas Lentoudis