Mapping The Disease Gene In SCA Families And The Frequency Distribution Analysis Of Different Subtypes Of SCA In Hans Of China

Spinocerebellar ataxias (SCA) are a clinically and genetically heterogeneous group of neurodegenerative disorders. Most of the SCA subtype are inherited as autosomal dominant traits. Since the identification of the first gene responsible for spinocerebellar ataxia type 1 (SCA1) in 1993, an increasing number of genes and chromosomal loci have been characterized. To date, genetic linkage and molecular genetic studies have identified at least 27 genetically distinct subtypes of SCA, demonstrating predominant genetic heterogeneity in these hereditary disorders.We described a family from Wang Cheng county of Hunan province with later-onset, slowly progressive, autosomal dominant cerebellar ataxia. Eight affected family members were evaluated. The age at onset ranged from 40 to 52 years, the mean age was 47.25 ± 4.37 years with no evidence of anticipation. The first symptoms were mild ataxia. while patients with longer disease duration developed spasmodic torticollis. Brain magnetic resonance imaging study of 2 affected patients showed that atrophy was confined to the cerebellum. Genetic analysis excluded the presence of pathological repeat CAG trinucleotide expansions in...