Ataxia espinocerebelosa tipo 8. Descripción de una familia

Abstract

Over the past decade, from the genetic point of view, several of the entities included in the group of hereditary ataxias have been identified. We report a Spanish family with type 8 spinocerebellar ataxia (SCA8), one of the most recent hereditary ataxias to be described from the clinical and genetic points of view. A 59 year old woman consulted us complaining of progressive dysarthria and unsteady gait. The only abnormal findings on neurological examination were those of cerebellar involvement. The patient s mother had a similar condition, characterized by difficulty in speaking which started when she was 62 years old and progressed to anarthria. Cranial magnetic resonance showed the presence of cerebellar atrophy with no signs of atrophy of the brainstem. On electromyographic studies there were no signs of neuropathy. Visual, auditory and sensory evoked potentials were normal. Genetic studies showed expansion of trinucleotide CTG (112 repetitions in the expanded allele and 28 repetitions in the normal allele) on the gene responsible for SCA8. SCA8 should be included in the differential diagnosis of progressive cerebellar syndromes, especially when changes in speech predominate with regard to other cerebellar signs.