Another HDAC inhibitory compound with a promising effect in SMA treatment is hidroxyurea.In cultured lymphocytes from SMA patients, hidroxyurea is able to increase the ratioof full–length to truncated SMN messenger RNA, the SMN protein level and intranucleargems number (the structures containing SMN protein) [20]. This evidence concerns the gene SMN2 and proximal spinal muscular atrophy.