It’s important to buy from a Heeler breeder who does genetic disease panel testing and understands the results. There are 10 main genetic diseases that should be tested for in the Mini Heelers. 8 of the genetic diseases in dogs are inherited in an Autosomal Recessive manner in dogs meaning that a puppy must receive 2 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 born to carrier parents has a 25% chance of inheriting the disease and a 50% chance of inheriting one copy of the gene and becoming a carrier. This is why reliable genetic testing is important for determining breeding practices. In order to eliminate the mutations 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.
The other 2 diseases found in Heelers are Cystinuria (ACD type) which is transferred in an Autosomal Dominant manner and Primary Lens Luxation or PLL which is inherited in an Autosomal Incomplete Dominant manner.
Cystinuria (ACD type), which is inherited in an Autosomal manner in dogs meaning that they only need to inherit one copy of the mutated gene from a parent to develop the disease. Dogs identified to have the genetic Mutation are expected to have features of the disease, though symptoms can be very mild and dogs may appear healthy. Each pup that is born to a single affected parent has a 50% chance of inheriting one copy of the gene mutation and having the disease. If both parents are affected, the chance of having affected offspring increases to 75-100%. 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 is not recommended. Australian cattle dogs that are not carriers of the mutation have no increased risk of having affected pups.
Primary lens luxation is inherited in an autosomal incomplete dominant manner in dogs meaning that dogs only need to inherit one copy of the mutated gene to be at an increased risk of developing the disease. Though lens luxation is most commonly seen in dogs having two copies of the mutated gene, carrier dogs have a low, but increased risk of lens luxation. Thus, dogs that have one or two mutant copies of the gene are considered at-risk for lens luxation. Reliable genetic testing is important for determining breeding practices. Because symptoms may not appear until adulthood, genetic testing should be performed before breeding.