Research in Huntington's disease (HD), a neurodegenerative diseases caused by trinucleotide repeat expansion in the gene (HTT) coding for the huntingtin protein, revealed that mutant huntingtin directly interacts with HAT proteins, leading to altered histone acetylation (Steffan et al., 2000; Jiang et al., 2006). This evidence concerns the gene HTT and juvenile Huntington disease.