Blended phenotype of adult-onset Alexander disease and spinocerebellar ataxia type 6.

Abstract

Alexander disease is an autosomal dominant hereditary disease characterized by progressive spastic paraplegia, ataxia, and bulbar symptoms caused by mutations in the glial fibrillary acidic protein ( GFAP ) gene. Previous nation-wide surveillance revealed that the prevalence rate in Japan is estimated at 1 in 2.7 million people.1 Meanwhile, SCA6 is an autosomal dominant spinocerebellar ataxia characterized by adult-onset pure cerebellar ataxia. The prevalence of SCA6 is estimated to be 1 in 100,000 people in Japan.2 Here, we report an extremely rare case presenting with a blended phenotype of adult-onset Alexander disease and SCA6. The authors thank Shoko Watanabe, PhD, for technical assistance including mutational analysis.