MATERNAL TRANSMISSION IN SPORADIC HUNTINGTONS-DISEASE

Huntington's disease is an autosomal dominant neurodegenerative disord er caused by the expansion of a (GAG), repeat in the IT15 gene. Three per cent of cases are sporadic and in those in which family studies ha ve been performed, the origin of the mutation was always paternal. The first sporadic case of Huntington's disease is presented in which a p remutated maternal allele of 37 CAG repeats was transmitted expanded t o the proband (43 CAG repeats). Molecular analysis of the IT15 gene is extremely important in sporadic cases of Huntington's disease, provid ing correct diagnosis of the disorder and facilitating genetic counsel ling to the family members.