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cross-references identify native condition entries. Ancestor membership does not transfer phenotype values between groups.","importantHtml":""},"sections":[{"bodyHtml":"

NARP results from mutations in the MT-ATP6 gene. This gene is contained in mitochondrial DNA, also known as mtDNA. Mitochondria are structures within cells that convert the energy from food into a form that cells can use. Although most DNA is packaged in chromosomes within the nucleus, mitochondria also have a small amount of their own DNA, known as mitochondrial DNA or mtDNA.

The MT-ATP6 gene provides instructions for making a protein that is essential for normal mitochondrial function. Through a series of chemical reactions, mitochondria use oxygen and simple sugars to create adenosine triphosphate (ATP), the cell's main energy source. The MT-ATP6 protein forms one part (subunit) of an enzyme called ATP synthase, which is responsible for the last step in ATP production. Mutations in the MT-ATP6 gene alter the structure or function of ATP synthase, reducing the ability of mitochondria to make ATP. It remains unclear how this disruption in mitochondrial energy production leads to muscle weakness, vision loss, and the other specific features of NARP.

MedlinePlus Genetics: Causes

","key":"forms","title":"What causes Neuropathy, ataxia, and retinitis pigmentosa?"},{"bodyHtml":"

Learning disabilities and developmental delays are often seen in children with NARP, and older individuals with this condition may experience a loss of intellectual function (dementia). Other features of NARP include seizures, hearing loss, and abnormalities of the electrical signals that control the heartbeat (cardiac conduction defects). These signs and symptoms vary among affected individuals.

Source: MedlinePlus Genetics

","key":"overview","title":"Condition overview"}],"sharedSources":[],"slug":"neuropathy-ataxia-and-retinitis-pigmentosa","sourceDocuments":[{"name":"Neuropathy, ataxia, and retinitis pigmentosa","reviewed":"2006-11","sections":{"causes":{"fetchedAt":"2026-10-20T20:23:45.881775+00:00","label":"Causes","pageSha256":"8e754f77648ef4fc7cc3940d4bdc9a14b6c1636c28d1e2cc8e8bdeca968e9327","sourceUrl":"https://medlineplus.gov/genetics/condition/neuropathy-ataxia-and-retinitis-pigmentosa/#causes","status":"available"}},"source_release":"2026-10-01","url":"https://medlineplus.gov/genetics/condition/neuropathy-ataxia-and-retinitis-pigmentosa"}],"sourceNote":"MedlinePlus descriptions and Causes; original HPO annotations.","takeawayHtml":"Cause explanations are from MedlinePlus Genetics. Feature values below retain their original sources and patient groups.","title":"Neuropathy, ataxia, and retinitis pigmentosa"},"schemaVersion":1}