Abstract: Objective: To detect gene and analyze clinical manifestations of sporadic Huntington disease (HD). Methods: Non-denaturing polyacrylamide gel electrophoresis method was used to detect CAG repeat. Clinical manifestations were scored by UHDRS and MMSE. Results: 5 out of 11 sporadic HD patients had CAG expansions. 5 genetic diagnosis patients with late onset, average 47 years, had 40-48 CAG repeat, often with milder chorea and no marked intellectual decline. Conclusions: The diagnosis of sporadic HD patients was confirmed by genetic detect. The clinical manifestations of sporadic HD patients were different from those of patients with family history.

Key words: sporadic Huntington disease, Genetic diagnosis, clinical phenotype