The defective gene responsible for Friedreich's ataxia was identified over 20 years ago, but so far our ideas of how this gene causes the disease have been merely speculative. It was assumed that, as a result of the mutation, the gene could no longer be transcribed because this stretch of DNA was inaccessible. FMI Group Leader Marc Bühler and his team have now carried out experiments demonstrating that this is not the case and revealing what actually happens in Friedreich's ataxia.
Friedreich's ataxia is caused by a deficiency of the protein frataxin. Frataxin is essential for iron metabolism in mitochondria - the cellular components responsible for energy production. Accordingly, mitochondria are especially important in cells with substantial energy requirements, such as nerve cells or heart muscle. It is therefore not surprising that these cells are particularly affected in Friedreich's ataxia: patients with this condition experience degeneration of the large sensory neurons and spinocerebellar tracts, but also cardiomyopathy.