Hereditary ataxia (HA)

Hereditary ataxia (HA) is a progressive disease with clinical signs like hypermetria, loss of balance, incoordination of gait and intention tremor, which later progress to severe gait disturbances. In the breeds Old English Sheepdog and Gordon Setter first symptoms appear within the age of 5 months to 4 years. A variant in the RAB24 gene was identified to cause HA in these breeds. A mutation in the KCNIP4 gene causes HA in the breed Norwegian Buhund, while a mutation in the HACE1 gene was found in Norwegian Elkhounds. Affected puppies show clinical symptoms at an age between 4 and 20 weeks. The puppies slipped easily on the ground, occasionally fell over and had a hanging tail atypical for the breed. In the breed Australian Shepherd and Miniature American Shepherd, first signs like hypermetria, bunny-hopping and a wobbly and stiff gait on the pelvic limbs can be seen between 4 and 19 months. These uncoordinated movements and spasticity are worsening progressively and leading to inability to walk at the age of 30 to 44 months. Brain histology results revealed diffuse demyelination. A mutation in the PNPLA8 gene was identified to cause HA in this breed.