A new locus for a childhood onset, slowly progressive autosomal recessive spinocerebellar ataxia maps to chromosome 11p15

he cerebellar ataxias are a heterogeneous group of neurodegenerative disorders, characterised by symptoms and signs of cerebellar degeneration, pyramidal and extrapyramidal features, and variable polyneuropathy. Prominent clinical features are signs of cerebellar ataxia, such as uncoordinated gait and uncontrolled co-ordination of hand, speech, and eye movements, while (extra) pyramidal signs, such as retinal, cardiac, muscle and/or neuronal involvement, are less common. The clinical picture shows a large variation in age at onset and disease progression. Sporadic ataxias may be attributed to various toxic, inflammatory, paraneoplastic, metabolic, endocrinal, or malabsorption conditions. Hereditary ataxias consist of a large number of autosomal dominant ataxias and ataxias with an autosomal recessive and X-linked mode of inheritance. The remaining ataxias of unknown cause are referred to as idiopathic sporadic cerebellar ataxias. Most symptomatic ataxias can be diagnosed on the basis of a typical history or by simple laboratory tests. In hereditary ataxias family history is important. However, a negative family history cannot rule out autosomal recessive or X-linked ataxia and even autosomal dominantly inherited ataxia may be missed because of reduced penetrance, the early death of gene carriers before the onset of symptoms, imprinting effects, variable expression, adoption, or nonpaternity. 1