To better understand the mechanisms of the FMR1 gene reactivation, we undertook a systematic study of its epigenetic status, testing the acetylation and methylation of histones H3 and H4, in three different regions of the gene; promoter, exon 1 and exon 16 before and after treatment of FXS lymphoblastoid cell lines with 5-azadC for 7 consecutive days. Here, FMR1 is linked to fragile X syndrome.