In a SCA3 model using SCA3tr-Q78 instability was shown to be enhanced by reduction of cAMP response element-binding protein (CREB)-binding protein (CBP), a key regulator in dna repair, whereas treatment with histone deacetylase (HDAC) inhibitors seemed to protect against repeat instability [79]. This evidence concerns the gene CREBBP and Spinocerebellar ataxia type 3.