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| chronic_progressive_external_ophthalmoplegia [2026/09/08 12:33] – Scott Larson | chronic_progressive_external_ophthalmoplegia [2026/09/08 12:40] (current) – Scott Larson | ||
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| ===== Overview ===== | ===== Overview ===== | ||
| - | **CPEO** is a **mitochondrial myopathy** that predominantly affects the extraocular muscles and the levator palpebrae, producing slowly progressive, | + | **CPEO** is a **mitochondrial myopathy** that predominantly affects the extraocular muscles and the levator palpebrae, producing slowly progressive, |
| ===== Onset and Course ===== | ===== Onset and Course ===== | ||
| - | * Typical onset in **adulthood** (commonly 18–40 years), with **ptosis** often the first sign ((mcfarland)). | + | * Typical onset in **adulthood** (commonly 18–40 years), with **ptosis** often the first sign. |
| - | * **Slowly progressive** over years; forced ductions are free (myopathic, not restrictive) and **pupils are spared** | + | * **Slowly progressive** over years; forced ductions are free (myopathic, not restrictive) and **pupils are spared**. |
| - | * **" | + | * **" |
| + | * **Kearns-Sayre syndrome** defined as early-onset | ||
| ===== Genetics ===== | ===== Genetics ===== | ||
| - | * Most commonly caused by a **single large-scale mtDNA deletion** (sporadic), but also by **mtDNA point mutations** and **nuclear mtDNA-maintenance genes** (e.g., **POLG, RRM2B, TWNK**) ((li))((mcfarland)). | + | * Most commonly caused by a **single large-scale mtDNA deletion** (sporadic), but also by **mtDNA point mutations** and **nuclear mtDNA-maintenance genes** (e.g., **POLG, RRM2B, TWNK**). |
| - | * **Heteroplasmy** matters: mutant load is far higher in skeletal muscle than in blood, so **negative peripheral blood testing does not exclude CPEO** | + | * **Heteroplasmy** matters: mutant load is far higher in skeletal muscle than in blood, so **negative peripheral blood testing does not exclude CPEO**. |
| ===== Diagnostic Evaluation ===== | ===== Diagnostic Evaluation ===== | ||
| - | * **Clinical eye and systemic exam** — motility, lids, pupils, dilated fundus, cardiac review | + | * **Clinical eye and systemic exam** — motility, lids, pupils, dilated fundus, cardiac review. |
| - | * **Screening labs** — resting/ | + | * **Screening labs** — resting/ |
| - | * **Exclude mimics** — myasthenia gravis (AChR/MuSK antibodies), | + | * **Exclude mimics** — myasthenia gravis (AChR/MuSK antibodies), |
| - | * **Muscle biopsy** (most accurate single test) — **ragged-red fibers** (Gomori trichrome) and **COX-negative / SDH-hyperintense fibers**; also enables respiratory-chain enzyme assays | + | * **Muscle biopsy** (most accurate single test) — **ragged-red fibers** (Gomori trichrome) and **COX-negative / SDH-hyperintense fibers**; also enables respiratory-chain enzyme assays. |
| - | * **Genetic testing** — whole mtDNA sequencing plus long-range PCR for deletions; **muscle is the optimal tissue**; nuclear gene panels when multiple deletions/ | + | * **Genetic testing** — whole mtDNA sequencing plus long-range PCR for deletions; **muscle is the optimal tissue**; nuclear gene panels when multiple deletions/ |
| ===== Key Points ===== | ===== Key Points ===== | ||
| * No blood test is confirmatory; | * No blood test is confirmatory; | ||
| - | * A **negative blood mtDNA test does not rule out** the disease — proceed to muscle if suspicion is high ((li)). | + | * A **negative blood mtDNA test does not rule out** the disease — proceed to muscle if suspicion is high. |
| - | * Screen for and monitor **cardiac conduction disease**, a source of preventable morbidity/ | + | * Screen for and monitor **cardiac conduction disease**, a source of preventable morbidity/ |
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| - | ===== References ===== | + | |
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| - | - [[https:// | + | |
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| - | - [[https:// | + | |
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| ====Compare CPEO with Congenital Fibrosis of EOM (CFEOM)==== | ====Compare CPEO with Congenital Fibrosis of EOM (CFEOM)==== | ||
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| |Muscle biopsy |Ragged-red / COX-negative fibers; mitochondrial abnormalities| Not a mitochondrial biopsy diagnosis; muscle shows fibrosis/ | |Muscle biopsy |Ragged-red / COX-negative fibers; mitochondrial abnormalities| Not a mitochondrial biopsy diagnosis; muscle shows fibrosis/ | ||
| |Orbital MRI |Mild EOM atrophy with fatty/ | |Orbital MRI |Mild EOM atrophy with fatty/ | ||
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| + | ===== References ===== | ||
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| + | - [[https:// | ||
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