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.

亚历山大病是一种常染色体显性遗传性疾病，其特征是由神经胶质原纤维酸性蛋白（GFAP）基因突变引起的进行性痉挛性截瘫，共济失调和延髓症状。先前的全国监视显示，日本的患病率估计为270万人中的1。¹同时，SCA6是常染色体显性遗传的小脑共济失调，其特征是成人发作的纯小脑共济失调。在日本，SCA6的患病率估计为100,000人中的1人。²在这里，我们报告了一个非常罕见的病例，该病例表现为成人发病的亚历山大疾病和SCA6的混合表型。