A novel mutation of PDE8B Gene in a Japanese family with autosomal-dominant striatal degeneration.

BACKGROUND: Autosomal-dominant striatal degeneration is a rare autosomal-dominant neurodegenerative movement disorder characterized by slowly progressive parkinsonism. Recently, a mutation of the cyclic nucleotide phosphodiesterase 8B gene was reported to be a causal gene mutation of this disease. METHODS: We report on the clinical characteristics of 2 patients of a Japanese family with autosomal-dominant striatal degeneration and the result of gene mutation analysis of this family. RESULTS: Clinical features of the patients are slowly progressive parkinsonism and brain MRI showing high signal intensity in T2-weighted images in the striatum. We found a heterozygous nonsense mutation in the first exon of cyclic nucleotide phosphodiesterase 8B gene, which is predicted to disrupt all important functional domains of the cyclic nucleotide phosphodiesterase 8B protein. CONCLUSIONS: This family is the second family with autosomal-dominant striatal degeneration after the first German family, confirming that cyclic nucleotide phosphodiesterase 8B gene is the causative gene for this disease.