Cerebellar abiotrophy (CA)

Cerebellar abiotrophy (CA) is an inherited neurological disorder characterised by pathological changes in the cerebellum. Affected dogs predominantly show degeneration of the Purkinje cells and the granular cell layer of the cerebellum, both of which play a key role in information processing and the coordination of movement.

In the Australian Kelpie, two risk markers have been identified that are associated with CA. Clinically, affected animals show a pronounced ataxia, often accompanied by head tremor, reduced body coordination, a wide-based stance of the hind limbs, and a gait in which the legs are lifted excessively high when walking (high-stepping gait).

One of the two risk markers is located in the LINGO3 gene and follows an autosomal recessive mode of inheritance with incomplete penetrance (current knowledge suggests that around 42% of affected dogs show clinical signs). First symptoms associated with this variant may appear as early as 4 to 10 weeks of age. The severity of symptoms is highly variable, meaning that even among puppies of the same age, both marked ataxia and only occasional balance issues may be observed.

The second risk marker in the VPM1 gene causes CA with a later onset of clinical signs (between 4 and 6 months of age or even later) and follows an autosomal recessive mode of inheritance with complete penetrance.