Spastic ataxia / ARSACS (SACS-related) - Pyrenean Mountain Dog

What does this test examine?

This genetic test analyses the SACS variant c.12731_12734del in the Pyrenean Mountain Dog. The condition is known as spastic ataxia, SACS-related ataxia, cerebellar ataxia, neuronal degeneration and an ARSACS-like disorder. SACS encodes sacsin, a large protein important for nerve cell health, especially in the cerebellum, spinal cord and peripheral nerves.

What does spastic ataxia mean?

Spastic ataxia is an inherited neurological disorder in which coordination, posture, gait and muscle control progressively deteriorate. Affected puppies can show clumsiness, uncoordinated movement, tremors and difficulty with slippery floors or stairs from around four months of age. As the disorder progresses, hind limb weakness, stiffness, balance problems and loss of mobility become more pronounced.

• N/N: the tested SACS deletion was not detected.
• N/del: one copy is present; the dog is a carrier and can pass the variant on.
• del/del: two copies cause the tested SACS-related spastic ataxia.

Practical value of this test

This test is highly valuable for Pyrenean Mountain Dog breeders because carriers can look healthy while still producing affected puppies if paired with another carrier. The result makes it possible to identify carriers, avoid risk matings and preserve healthy breeding lines responsibly. For owners, it gives clear genetic information when neurological signs, loss of coordination or relevant family history are present.

• Helps avoid matings that can produce puppies with two copies of the deletion.
• Supports deliberate carrier management without unnecessarily losing valuable lines.
• Gives clear information for young dogs with coordination or movement problems.
• Supports breed-focused health selection for a serious progressive disorder.

Inheritance and interpretation

The trait is inherited in an autosomal recessive manner. A carrier is usually not affected, but can pass the deletion on. When two carriers are bred together, some offspring can inherit two copies and develop the disorder. A dog with two copies has the genotype that causes the tested SACS-related spastic ataxia.