Splice Mutation in the Iron-Sulfur Cluster Scaffold Protein ISCU Causes Myopathy with Exercise Intolerance

Fanny Mochel, Melanie A. Knight, Wing Hang Tong, Dena Hernandez, Karen Ayyad, Tanja Taivassalo, Peter M. Andersen, Andrew Singleton, Tracey A. Rouault, Kenneth H. Fischbeck, Ronald G. Haller

Research output: Contribution to journalArticlepeer-review

183 Scopus citations


A myopathy with severe exercise intolerance and myoglobinuria has been described in patients from northern Sweden, with associated deficiencies of succinate dehydrogenase and aconitase in skeletal muscle. We identified the gene for the iron-sulfur cluster scaffold protein ISCU as a candidate within a region of shared homozygosity among patients with this disease. We found a single mutation in ISCU that likely strengthens a weak splice acceptor site, with consequent exon retention. A marked reduction of ISCU mRNA and mitochondrial ISCU protein in patient muscle was associated with a decrease in the iron regulatory protein IRP1 and intracellular iron overload in skeletal muscle, consistent with a muscle-specific alteration of iron homeostasis in this disease. ISCU interacts with the Friedreich ataxia gene product frataxin in iron-sulfur cluster biosynthesis. Our results therefore extend the range of known human diseases that are caused by defects in iron-sulfur cluster biogenesis.

Original languageEnglish (US)
Pages (from-to)652-660
Number of pages9
JournalAmerican Journal of Human Genetics
Issue number3
StatePublished - Mar 3 2008

ASJC Scopus subject areas

  • Genetics
  • Genetics(clinical)


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