LNA structure and LNA/DNA mixmer sequences. (a) Chemical structures of RNA and phosphorothioated LNA. (b) LNA/DNA mixmer sequences targeting SMN2 intron 7. DNA base: G, A, T, C. LNA base (red): +G, +A, +T, +C. Phosphorothioated DNA base: G*, A*, T*, C*. Phosphorothioated LNA base (red): +G*, +A*, +T*, +C*.