Lethal Acrodermatitis (LAD) is an autosomal recessive disease that is seen in Bull Terriers. LAD puppies cannot absorb zinc and also cannot be successfully supplemented, with zinc. LAD causes poor growth, thick skin, and painful skin lesions which can turn into secondary bacterial or yeast infections that eventually lead to death before the dog reaches two years of age. The commonly affected areas due to this disease are the muzzle, ears, feet, legs, and groin. The immune system also does not function to the optimum level, no matter how mildly or severely the Bull Terrier puppy is affected.
Most breeders can recognize the disease in the puppy by the time it is six to eight weeks old because it is less than half the size of the other puppies in the litter and has flat, splayed feet with dermatitis. However, since only Bull Terriers have this genetic problem, a Veterinarian may not be initially aware of it when examining an affected patient.
The Lethal Acrodermatitis gene mutation is recessive - this means that a dog must inherit two copies of the mutation, one from each parent, to be clinically affected by LAD. Dogs with one copy of the defective gene and one copy of the normal gene are called carriers, and show no signs of disease but can pass the defective gene onto their offspring.
It is only possible to identify carriers with DNA testing. Dogs fall into three categories, CLEAR of the mutated gene, a CARRIER of the mutated gene and AFFECTED by the mutated gene (LAD). When two carriers are bred, 25% (on average) of the offspring will be affected by the disease, 25% will be clear and the remaining 50% will themselves be carriers.
Dogs that are affected by LAD, are referred to as Zincers.
The LAD genetic test has only been available since 2017. As breeders utilize this new genetic testing, they are responsibly breeding away from LAD. It is an accepted practice to breed a CLEAR animal to a CARRIER animal, as they will not produce affected puppies. NEVER should a CARRIER be bred to a CARRIER, please refer to the chart below.
If your Bull Terrier has Lethal Acrodermatitis, the symptoms will most likely be evident by the time your dog is about 3-6 weeks old. The usual symptoms of Lethal Acrodermatitis are:
Sadly, Lethal Acrodermatitis is almost always fatal. In rare cases, a Bull Terrier can live for several years with Lethal Acrodermatitis but the quality of life is compromised. If your Bull Terrier is in constant severe pain, the most humane option to do is euthanization. You and your vet are the best judges of your Bull Terrier's quality of life.
When contemplating breeding, it is recommended that both dogs and bitches be screened for LAD. It is a simple cheek swab that can be done by the owner of the bitch or stud dog and submitted to a laboratory who tests for this disease.
Genetic testing of the MLKN1 gene will reliably determine whether a dog is a genetic carrier of lethal acrodermatitis. This disease is inherited in an “Autosomal Recessive” manner in dogs meaning that they must receive two copies of the mutated gene (one from each parent) to develop the disease. In general, carrier dogs do not have features of the disease but when bred with another carrier of the same mutation, there is a risk of having affected pups. Each pup that is born to this pairing has a 25% chance of inheriting the disease and a 50% chance of inheriting one copy and being a carrier of the MLKN1 gene mutation. Reliable genetic testing is important for determining breeding practices. In order to eliminate this mutation from breeding lines and to avoid the potential of producing affected pups, breeding of known carriers to each other is not recommended. Dogs that are not carriers of the mutation have no increased risk of having affected pups.
A. (CLEAR/NORMAL):
These dogs have two copies of the normal gene and will neither develop Lethal Acrodermatitis nor pass this mutation to their offspring.
B. (CARRIER/NOT AFFECTED):
These dogs have one copy of the normal gene and one copy of the mutation associated with this disease. They will not develop Lethal Acrodermatitis but will, if bred, pass the mutation to 50% of its offspring, on average.
C. (AT RISK/AFFECTED):
These dogs have two copies of the mutation associated with Lethal Acrodermatitis which results in a severe skin condition with swelling and cracked skin lesions.
