What are the genetic changes related to ataxia neuropathy spectrum ?
Ataxia neuropathy spectrum is caused by mutations in the POLG gene or, rarely, the C10orf2 gene.  The POLG gene provides instructions for making one part, the alpha subunit, of a protein called polymerase gamma (pol ). The C10orf2 gene provides instructions for making a protein called Twinkle. Pol  and Twinkle function in mitochondria, which are structures within cells that use oxygen to convert the energy from food into a form cells can use. Mitochondria each contain a small amount of DNA, known as mitochondrial DNA (mtDNA), which is essential for the normal function of these structures. Pol  and Twinkle are both integral to the process of DNA replication by which new copies of mtDNA are produced.  Mutated pol  or mutated Twinkle reduce mtDNA replication. Although the mechanisms are unknown, mutations in the POLG gene often result in fewer copies of mtDNA (mtDNA depletion), and mutations in the C10orf2 gene often result in deletions of large regions of mtDNA (mtDNA deletion). MtDNA depletion or deletion occurs most commonly in muscle, brain, or liver cells. MtDNA depletion causes a decrease in cellular energy, which could account for the signs and symptoms of ataxia neuropathy spectrum. It is unclear what role mtDNA deletions play in the signs and symptoms of the condition.