The present invention provides means and methods for counteracting and/or preventing aggregation of a polyQ protein. Further provided are improved poly constructs which are, amongst other things, useful for testing assays. According to the invention, several peptidases like, e.g. tripeptidyl peptidase II (TPPII), appear to be capable of cleaving long polyQ peptides comprising at least 45 glutamine residues. Hence, according to the invention, administration of such peptidases to an individual suffering from a polyQ expansion disorder results in degradation of long polyQ peptides.
