Spino‐cerebellar ataxia in Western Norway

The cerebellar ataxia of Marie (SCA) was investigated in Western Norway, a region with a population of 725,000, and with several isolated communities. Two modes of transmission were found: autosomal dominant SCA segregating in four families, and autosomal recessive SCA segregating in nine families. Within the second category, two distinct clinical types were observed. One exhibited ataxia with additional spinal involvement, including both upper and lower motor neuron affection and sensory disturbances. In some cases there were also ophthalmoplegias, dementia, epilepsy, and Parkinsonian signs. The other type exhibited mostly ataxic signs with little additional spinal involvement, but with dementia, epilepsy, and ophthalmoplegias in some cases, and occasionally hyperkinesia and optic nerve atrophy. The autosomal dominant SCA cases showed a varied spino‐cerebellar symptomatology, but lacked ocular signs and had less mental disturbances than recessive SCA. Additionally, the disease course was more benign in autosomal dominant than in autosomal recessive SCA. The dominant form did not affect life expectancy, whereas autosomal recessive SCA considerably reduced the life span.In four fami