Hereditary neurodegenerative disease of the cerebellum described in the Italian Spinone. It produces progressive degeneration of the cerebellar cortex, with loss of Purkinje cells, which compromises movement coordination and balance. Affected dogs develop ataxia that impairs walking, standing and exercise. It is incurable and, although it does not cause pain, it ultimately severely limits quality of life.

Applicable breed: Italian Spinone. Before the test became widespread, the disease was relatively common in European working lines; there is no consolidated epidemiology with published carrier frequencies (limited data).

- Progressive ataxia that starts in the pelvic limbs and extends to the thoracic limbs
- Hypermetria and dysmetria of movements
- Intention tremor of the head and neck
- Wide-based stance gait
- Difficulty climbing stairs, jumping and turning
- Preservation of mental state and appetite
- Slow progression over months

Hereditary cerebellar ataxia of the Italian Spinone was recognized as a clinical entity in the late 1990s and early 2000s, with case series published by European veterinary neurologists (Forman, De Risio and colleagues). The molecular basis was identified several years later: an intronic repeat expansion in the ITPR1 gene (inositol 1,4,5-trisphosphate receptor type 1) as the cause of the disease. The finding made it possible to develop a carrier genetic test now used in the breed's European breeding programmes.

- Test every breeding animal before mating
- Do not cross two carriers: 25 % of the litter would be affected
- A carrier may be crossed with a clear animal without risk of affected offspring; the offspring intended for breeding should be tested
- Do not automatically remove carriers: always mate them with clear animals to preserve genetic diversity

The differential diagnosis includes other hereditary cerebellar ataxias and acquired processes (inflammatory, toxic, neoplastic). Clinical onset is usually in the first months or years of life, from 4 months of age. MRI shows cerebellar atrophy, especially of the vermis. There is no curative treatment; management is supportive and involves adapting the environment.

1. Forman OP et al. 2015, Spinocerebellar ataxia in the Italian Spinone dog is associated with an intronic GAA repeat expansion in ITPR1. Mamm Genome 26(1-2):108-17. PMID: 25354648. OMIA:002097-9615.