The present invention provides, among other things, methods and compositions for effective delivery of messenger RNA (mRNA) to the central nervous system (CNS). In particular, the present invention provides methods and compositions for administering intrathecally to a subject in need of delivery a composition comprising an mRNA encoding a protein, encapsulated within a liposome, such that the administering of the composition results in the intracellular delivery of mRNA in neurons in the brain and/or spinal cord. The present invention is particularly useful for the treatment of CNS diseases, disorders or conditions, such as spinal muscular atrophy.
