Scott syndrome / haemorrhagic diathesis (ANO6-related) - Dog

What does this test assess?

This genetic test assesses the ANO6 splice-site variant c.1934+1G>A associated with Scott syndrome in dogs. The condition is also known as Canine Scott Syndrome (CSS), Canine Platelet Procoagulant Deficiency, Platelet Factor X Receptor Deficiency, Deficiency of Platelet Receptor for Factor X and haemorrhagic diathesis. It is a rare inherited bleeding disorder in which platelets are present but show insufficient procoagulant activity.

Why is this test useful?

Affected dogs may show bruising, post-surgical haematomas, nosebleeds and bleeding into joints or soft tissues. Routine coagulation tests, platelet count and von Willebrand screening can be normal, which means the disorder can be difficult to recognise without DNA testing or specialised platelet-function testing. Knowing the genetic status is therefore useful for breeding plans and for medical preparation when a procedure or surgery is planned.

The variant lies in the ANO6 gene, also known as TMEM16F. ANO6 is involved in exposing phosphatidylserine on activated platelets. This surface is needed for coagulation complexes to work efficiently. When this function is deficient, conversion of prothrombin to thrombin can be impaired, while other platelet functions may appear relatively normal.

How should the result be read?

• G/G: no copy of the tested variant detected.
• G/A: carrier; usually clinically healthy, but able to pass the variant on.
• A/A: genotype associated with Scott syndrome; inform the veterinarian, especially before surgery or when bleeding signs occur.

The condition follows autosomal recessive inheritance. This test specifically assesses the variant c.1934+1G>A; other causes of abnormal bleeding are not excluded by this test.