DNA Testing for the English Mastiff

DNA testing is available for early detection of a variety of diseases that affect any breed of dog, including the English Mastiff.  This involves taking a cheek swab and sending to the lab for analysis.

It's important to choose tests for the specific breed and Vetgen offers testing for 6 diseases that can affect the English Mastiff. Currently the OEMC offers a subsidy to its members for Cystinuria and Pied testing.


Cystinuria is a genetic defect in the kidney tubules. Normal kidneys filter the amino acid cystine and do not allow it to go into the urine. In dogs with cystinuria, this filtering action fails, and cystine passes into the urine, where it can form crystals and/or stones (uroliths). If stones form, they can block the urethra and obstruct urinary flow, especially in males. 

In most breeds, this is an autosomal recessive disease thus an animal affected with the disease has inherited one copy of the mutation from each parent.

Inheriting only one copy from one parent yields carrier status. The disease is not present but the animal must be bred carefully to prevent creating affected offspring.

CMR1 - Canine Multifocal Retinopathy

CMR symptoms are very similar to Best macular dystrophy disease (BMD) in humans. CMR is a retinal disorder caused by a gene mutation which causes pigment epithelium athrophy.  Rose-grey coloured lesions can be seen in both eyes which are of different sizes and shapes.  Affected puppies generally show their first symptoms in their first year with Total blindness occurring later in life.

CMR1 is an autosomal recessive disorder. The disease affects dogs with P/P (positive / positive) genotype only. Dogs with P/N (positive /negative) genotype are clinically without any symptoms. They are genetically considered carriers of the disease (heterozygotes).

DM - Degenerative myelopathy

Is a progressive disease of the spinal cord in older dogs. The disease has an insidious onset typically between 8 and 14 years of age. It begins with a loss of coordination (ataxia) in the hind limbs. The affected dog will wobble when walking, knuckle over or drag the feet, there is progressive limb weakness and muscle loss, tremors, difficulty rising, and stumbling. Affected animals develop spinal and hind end problems later in life. It is inherited as a recessive disease based on these mutations, but there is also ongoing work to determine other factors that may play a role in severity and age of onset.


Inherited hyperuricosuria (HU) causes dogs to produce urine with very high levels of uric acid. (I liken this to Gout in humans and must be extremely painful).  This can lead to bladder stones, and less frequently kidney stones. The disease is inherited as an autosomal recessive trait.

MTC - Macrothrombocytopenia

This is an inherited blood disorder.  It is inherited as an autosomal dominant trait.  The name is derived from the words macro (large) and thrombocyte (platelets), cells that assist in the blood clotting function.


The Progressive Retinal Atrophy, also known as "PRA" is an inherited disease that causes degeneration of the retina. The light-sensitive cells of the retina gradually die, because of insufficient blood vessels.

Degeneration of the retina results first in night blindness and can be identified in puppies at six weeks of age.  The night blindness progresses gradually to blindness and at the age of 1 to 2 years, most dogs affected with this disease are totally blind.

The AD-PRA is an autosomal dominant inherited disease  which means that only one copy of the mutated gene causes the disease occurrence in dogs. There are only healthy dogs or affected dogs; there are no carriers of this disease.

Pied Testing

Subsidised to OEMC members. The standard does not allow for excessive amounts of White (‘Excessive white on body, chest or feet is unacceptable’). Put simply, the gene that suppresses colour can also suppress the hair follicles in the inner ear causing deafness.