Myoclonic epilepsy with red ragged fibers (MERRF)
Last revised by Rohit Sharma on 4 Jul 2024
Citation, DOI, disclosures and article data
Citation:
Knipe H, Sharma R, St-Amant M, et al. Myoclonic epilepsy with red ragged fibers (MERRF). Reference article, Radiopaedia.org (Accessed on 02 Aug 2024) https://doi.org/10.53347/rID-39666
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rID:
39666
Article created:
15 Sep 2015,
Henry Knipe ◉
Disclosures:
At the time the article was created Henry Knipe had no recorded disclosures.
View Henry Knipe's current disclosures
Last revised:
4 Jul 2024,
Rohit Sharma ◉
Disclosures:
At the time the article was last revised Rohit Sharma had no financial relationships to ineligible companies to disclose.
View Rohit Sharma's current disclosures
Revisions:
14 times, by
8 contributors -
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- Myoclonic epilepsy with red-ragged fibres (MERRF)
Myoclonic epilepsy with red ragged fibers (MERRF) is a rare multisystem mitochondrial disorder.
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Clinical presentation
Patients usually present in late adolescence or early adulthood. The clinical presentation can be highly variable, including 1-4:
epilepsy, typically with myoclonic seizures but other seizures types can also occur
myoclonus (independent of epilepsy)
cerebellar ataxia
intellectual disability or dementia
visual loss due to optic atrophy
proximal myopathy
peripheral neuropathy
short stature
cervical (neck) lipomas
Pathology
The diagnosis of MERRF is based on clinical symptoms (e.g. myoclonic epilepsy and ataxia) and ragged-red fibers on muscle biopsy 3,4.
Genetics
The mitochondrial gene MT-TK, which encodes tRNALys, is the most commonly affected with an A-to-G transition at nucleotide 8344 (80%) 3,4.
Markers
serum and CSF lactic acidosis 4
high CSF protein
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Radiographic features
Neuroradiological features of MERRF can be seen on CT and/or MRI 1,2:
brainstem atrophy
globus pallidus atrophy +/- calcification
dentate nucleus calcification
Differential diagnosis
On imaging consider:
MELAS: differentiated by the presence of strokes in MELAS
References
- 1. Ito S, Shirai W, Asahina M et-al. Clinical and brain MR imaging features focusing on the brain stem and cerebellum in patients with myoclonic epilepsy with ragged-red fibers due to mitochondrial A8344G mutation. AJNR Am J Neuroradiol. 2008;29 (2): 392-5. doi:10.3174/ajnr.A0865 - Pubmed citation
- 2. Diagnostic Radiology: Paediatric Imaging. Jp Medical Ltd. ISBN:9350252058. Read it at Google Books - Find it at Amazon
- 3. DiMauro S, Hirano M. MERRF. 2003 Jun 3 [Updated 2015 Jan 29]. In: Pagon RA, Adam MP, Ardinger HH, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2015. Available from: http://www.ncbi.nlm.nih.gov/books/NBK1520/
- 4. Schapira A. Mitochondrial Dna and Disease. CONTINUUM: Lifelong Learning in Neurology. 2008;14:133-48. doi:10.1212/01.con.0000275629.24690.30
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