DM
DM is an incompletely penetrant autosomal recessive disease, usually affecting dogs 5 years of age or older. The mutation tested for in Corgis is SOD1:c.118A, referred to as SOD1-A or exon 2.
Tests identify Corgis as 'Clear' with no mutated genes, 'Carrier' with one copy of the mutated gene, and 'At Risk' with two copies of the mutated gene.
Corgis shown as 'At Risk' will not necessarily develop the disease. Other genetic and/or environmental factors may influence whether a dog will develop the disease.
VWD1
Von Willebrands disease (vWD) is a blood disease caused by a deficiency of von Willebrand Factor (vWF), an adhesive glycoprotein in the blood required for normal blood clotting.
A lack of vWF impairs platelet stickiness and clumping. Symptoms can include: spontaneous hemorrhage from mucosal surfaces, nosebleeds, blood in the feces, bloody urine, bleeding gums, excessive vaginal bleeding, bruising, prolonged bleeding after surgery or trauma, blood loss anemia.
The milder form (Type I) may be autosomal recessive or incompletely dominant. This is the most common hereditary blood clotting disorder in Corgis.
EIC
Affected Corgis have normal muscle mass, normal patellar reflexes before an episode of EIC, normal findings on muscle biopsy, and are capable of moderate exertion without showing signs.
Signs begin within 2 minutes after cessation of 5 to 15 minutes of strenuous exercise. Affected Corgis develop a wobbly gait with hindlimb weakness and incoordination, wide based stance, and walking with crouched hind legs. Signs can progress to full body weakness, extensor rigidity, confusion, loss of consciousness, and rarely death. Episodes frequently last 5-10 minutes, often with complete recovery after 30 minutes. Loss of patellar reflexes persists after initial recovery.