Pseudoexon exclusion by antisense therapy in methylmalonic aciduria (MMAuria)

Hum Mutat. 2009 Dec;30(12):1676-82. doi: 10.1002/humu.21118.


Development of pseudoexon exclusion therapies by antisense modification of pre-mRNA splicing represents a type of personalized genetic medicine. Here we present the cellular antisense therapy and the cell-based splicing assays to investigate the effect of two novel deep intronic changes c.1957-898A>G and c.1957-920C>A identified in the methylmalonyl-coenzyme A (CoA) mutase (MUT) gene. The results show that the nucleotide change c.1957-898A>G is a pathological mutation activating pseudoexon insertion and that antisense morpholino oligonucleotide (AMO) treatment in patient fibroblasts leads to recovery of MUT activity to levels 25 to 100% of control range. On the contrary, the change c.1957-920C>A, identified in two fibroblasts cell lines in cis with c.1885A>G (p.R629G) or c.458T>A (p.D153V), appears to be a rare variant of uncertain clinical significance. The functional analysis of c.1885A>G and c.458T>A indicate that they are the disease-causing mutations in these two patients. The results presented here highlight the necessity of scanning the described intronic region for mutations in MUT-affected patients, followed by functional analyses to demonstrate the pathogenicity of the identified changes, and extend previous work of the applicability of the antisense approach in methylmalonic aciduria (MMAuria) for a novel intronic mutation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Cell Line
  • Exons / genetics*
  • Genotype
  • Humans
  • Introns / genetics
  • Metabolism, Inborn Errors / drug therapy*
  • Metabolism, Inborn Errors / enzymology
  • Methylmalonyl-CoA Mutase / deficiency
  • Molecular Sequence Data
  • Mutation / genetics
  • Oligonucleotides, Antisense / therapeutic use*
  • Phenotype
  • Propionates / metabolism
  • RNA Splicing / genetics


  • Oligonucleotides, Antisense
  • Propionates
  • Methylmalonyl-CoA Mutase
  • propionic acid