VERY LATE-ONSET FRIEDREICHS ATAXIA WITHOUT CARDIOMYOPATHY IS ASSOCIATED WITH LIMITED GAA EXPANSION IN THE X25 GENE

Molecular analysis of spinocerebellar ataxias revealed a pathologic GA A expansion in the gene encoding frataxin in six adult patients from t hree families. These patients, carrying expanded alleles in the low-ra nge size, had an exceptionally late onset and lacked cardiomyopathy, p ointing to phenotypic variability of Friedreich's ataxia. Both mitotic and gametic instability of the expanded triplet repeat were present i n these families.