Therapeutic approaches for spinal muscular atrophy (SMA)

Gene Ther. 2017 Sep;24(9):514-519. doi: 10.1038/gt.2017.45. Epub 2017 May 31.

Abstract

Spinal muscular atrophy is an autosomal recessive neurodegenerative disorder characterized by progressive muscle wasting and loss of muscle function due to severe motor neuron dysfunction, secondary to mutations in the survival motor neuron 1 (SMN1) gene. A second neighboring centromeric gene, SMN2, is intact in all patients but contains a C-to-T variation in exon 7 that affects a splice enhancer and determines exclusion of exon 7 in the majority of its transcript, leading to an unstable protein that cannot substitute for mutant SMN1. Following successful studies on disease models and intensive studies on SMN functions in the past decade, SMN upregulation targeting SMN2, has been suggested as a possible therapeutic approach. Recently, we have witnessed an historical turning point with the first disease-modifying treatment receiving Food and Drug Administration approval and now being available to patients also outside the clinical trial. This innovative treatment is an antisense oligonucleotide, which, administered intrathecally, is able to increase exon 7 inclusion in the majority of the SMN2 mRNA and increase the production of fully functional SMN protein. Alternative advanced therapies, such as viral vector mediated gene therapy and orally available small molecules, are also showing promising results in early clinical trial phases.

Publication types

  • Review
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Clinical Trials as Topic
  • Genetic Therapy / adverse effects
  • Genetic Therapy / methods*
  • Humans
  • Muscular Atrophy, Spinal / genetics
  • Muscular Atrophy, Spinal / therapy*
  • Oligonucleotides, Antisense / administration & dosage
  • Survival of Motor Neuron 1 Protein / genetics
  • Survival of Motor Neuron 1 Protein / metabolism
  • Survival of Motor Neuron 2 Protein / genetics
  • Survival of Motor Neuron 2 Protein / metabolism

Substances

  • Oligonucleotides, Antisense
  • SMN1 protein, human
  • SMN2 protein, human
  • Survival of Motor Neuron 1 Protein
  • Survival of Motor Neuron 2 Protein