MERRF Syndrome (Myoclonic Epilepsy and Ragged Red Fibers)

A mitochondrial encephalomyopathy characterized clinically by a mixed seizure disorder, myoclonus, progressive ataxia, spasticity, and a mild myopathy. Dysarthria, optic atrophy, growth retardation, deafness, and dementia may also occur. This condition tends to present in childhood and to be transmitted via maternal lineage. Muscle biopsies reveal ragged-red fibers and respiratory chain enzymatic defects. (From Adams et al., Principles of Neurology, 6th ed, p986)

Also Known As:

Networked: 119 relevant articles (0 outcomes, 4 trials/studies)

Disease Context: Research Results

Related Diseases

1.	Lactic Acidosis
2.	Stroke (Strokes)
3.	Mitochondrial Diseases (Mitochondrial Disease)
4.	Chronic Progressive External Ophthalmoplegia (Progressive External Ophthalmoplegia)
5.	Myoclonic Epilepsies (Myoclonic Encephalopathy)

Experts

1.	Wei, Yau-Huei: 10 articles (04/2014 - 01/2002)
2.	Ma, Yi-Shing: 7 articles (04/2014 - 01/2002)
3.	Hsieh, Mingli: 4 articles (04/2014 - 09/2011)
4.	Wu, Shi-Bei: 3 articles (04/2014 - 06/2010)
5.	Chi, Tang-Hao: 3 articles (04/2014 - 09/2011)
6.	Liu, Chin-San: 3 articles (12/2013 - 05/2005)
7.	Filosto, Massimiliano: 3 articles (05/2013 - 03/2002)
8.	Turnbull, Douglass M: 2 articles (06/2014 - 03/2009)
9.	Taylor, Robert W: 2 articles (06/2014 - 03/2009)
10.	Blakely, Emma L: 2 articles (06/2014 - 03/2009)

Drugs and Biologics

Drugs and Important Biological Agents (IBA) related to MERRF Syndrome:

1.	Mitochondrial DNA (mtDNA)IBA 04/01/2014 - "The most common mutation in MERRF syndrome, the A8344G mutation in mtDNA, has been associated with severe defects in the respiratory function of mitochondria. " 05/28/2013 - "Myoclonic epilepsy with ragged-red fibers (MERRF) is a rare mitochondrial syndrome, mostly caused by the 8344A>G mitochondrial DNA mutation. " 09/01/2011 - "The most common mutation in MERRF syndrome, A8344G mutation in mtDNA, has been associated with severe defects in protein synthesis. " 06/01/2010 - "Taken together, we suggest that mtDNA mutation-elicited oxidative stress, oxidative damage, and altered gene expression are involved in the pathogenesis and progression of MERRF syndrome." 06/01/2010 - "Mitochondrial DNA mutation-elicited oxidative stress, oxidative damage, and altered gene expression in cultured cells of patients with MERRF syndrome."
2.	Lys Transfer RNAIBA 12/01/2011 - "A mutation in tRNA(Lys) that causes myoclonic epilepsy with ragged-red fibers (MERRF) is also reported to prevent modification of the wobble U. " 10/15/2004 - "Our aim was to determine whether the A8344G mitochondrial tRNA(Lys) mutation, which can cause the MERRF (myoclonic epilepsy with ragged-red fibers) syndrome, could be complemented by targeting tRNAs into mitochondria from the cytosol. " 04/01/1995 - "Myoclonic epilepsy with ragged-red fibers (MERRF) is a maternally inherited disorder of oxidative phosphorylation due to specific point mutations within the mitochondrial tRNA(Lys) gene. " 06/01/1994 - "A much greater variability in respiratory capacity was observed among the transformants derived from the MERRF patient and was found to be related to the presence and amount of the mitochondrial tRNALys mutation associated with the MERRF syndrome. " 09/01/1993 - "Mitochondrial tRNA (lys) mutation at position 8344 was pointed out as previously reported in the MERRF syndrome."
3.	Superoxide DismutaseIBA 03/31/2001 - "On the other hand, we observed that the RNA, protein and activity levels of Mn-SOD are increased two- to three-fold in skin fibroblasts of the patients with CPEO syndrome but are dramatically decreased in patients with MELAS or MERRF syndrome. " 03/01/2002 - "A histochemical and immunohistochemical study was performed on muscle biopsies from 17 patients with mitochondrial disease [chronic progressive external ophthalmoplegia (CPEO), mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS), myoclonic epilepsy with ragged red fibers (MERRF)] to evaluate the expression pattern and location of manganese superoxide dismutase (MnSOD), copper-zinc superoxide dismutase (CuZnSOD) and reduced glutathione (GSH) in skeletal muscle fibers. "
4.	ZincIBA 03/01/2002 - "A histochemical and immunohistochemical study was performed on muscle biopsies from 17 patients with mitochondrial disease [chronic progressive external ophthalmoplegia (CPEO), mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS), myoclonic epilepsy with ragged red fibers (MERRF)] to evaluate the expression pattern and location of manganese superoxide dismutase (MnSOD), copper-zinc superoxide dismutase (CuZnSOD) and reduced glutathione (GSH) in skeletal muscle fibers. "
5.	Glutathione (Reduced Glutathione)IBA 03/01/2002 - "A histochemical and immunohistochemical study was performed on muscle biopsies from 17 patients with mitochondrial disease [chronic progressive external ophthalmoplegia (CPEO), mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS), myoclonic epilepsy with ragged red fibers (MERRF)] to evaluate the expression pattern and location of manganese superoxide dismutase (MnSOD), copper-zinc superoxide dismutase (CuZnSOD) and reduced glutathione (GSH) in skeletal muscle fibers. "
6.	CopperIBA 03/01/2002 - "A histochemical and immunohistochemical study was performed on muscle biopsies from 17 patients with mitochondrial disease [chronic progressive external ophthalmoplegia (CPEO), mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS), myoclonic epilepsy with ragged red fibers (MERRF)] to evaluate the expression pattern and location of manganese superoxide dismutase (MnSOD), copper-zinc superoxide dismutase (CuZnSOD) and reduced glutathione (GSH) in skeletal muscle fibers. "
7.	DNA (Deoxyribonucleic Acid)IBA 03/01/2012 - "Buccal swab analysis of mitochondrial enzyme deficiency and DNA defects in a child with suspected myoclonic epilepsy and ragged red fibers (MERRF)." 07/01/2001 - "Seizures in myoclonic epilepsy with ragged-red fibers detected by DNA analysis: a case report." 06/01/2010 - "Blood and muscle-derived DNA demonstrated a high level (92% and 82%, respectively) of the m.8344A>G mutation seen in patients with the mitochondrial cytopathy, ''myoclonic epilepsy with ragged red fibers on muscle biopsy.'' This infant's early presentation including inappropriate antidiuretic secretion due to presumed renal salt loss and rapid course appears to be unique to this mutation." 04/15/2009 - "Thus, the DNA biochip would potentially become a valuable tool in clinical specific screening of the mtDNA point mutations associated with MELAS and/or MERRF syndrome." 10/01/2008 - "Clearly, the DNA biochip combined with MAP method would become a valuable tool in multiplex detecting of the point mutations in mtDNA leading to MELAS and/or MERRF syndrome. "
8.	Mitochondrial encephalopathyIBA 03/01/1993 - "In the present case, the patient had a syndrome of both Mitochondrial Encephalopathy, Lactic Acidosis and Stroke like episodes (MELAS) and Myoclonic Epilepsy and Ragged Red Fibers (MERRF). " 04/01/1994 - "Some are well defined including the myoclonus epilepsy ragged red fibre syndrome (MERRF) and the mitochondrial encephalopathy lactic acidosis stroke like episode syndrome (MELAS). " 10/01/1992 - "The mitochondria become functionally defective when the amount of mutant mtDNA exceeds a certain threshold, which differs from mutation to mutation: 60 to 70% in chronic progressive external ophthalmoplegia (CPEO) and probably 95% in the syndromes of mitochondrial encephalopathy, myopathy, lactic acidosis, and stroke-like episodes (MELAS), and myoclonic epilepsy with ragged red fibers (MERRF). " 01/01/2006 - "There are several mitochondrial DNA (mtDNA) point mutations responsible for common mitochondrial diseases such as mitochondrial encephalopathy, lactic acidosis, stroke-like events, myoclonic epilepsy and ragged red fibers, neuropathy, ataxia, retinitis pigmentosa, and Leber's hereditary optic neuropathy. " 01/01/2012 - "There are a set of recurrent point mutations in the mitochondrial DNA (mtDNA) that are responsible for common mitochondrial diseases, including MELAS (mitochondrial encephalopathy, lactic acidosis, stroke-like episodes), MERRF (myoclonic epilepsy and ragged red fibers), LHON (Leber's hereditary optic neuropathy), NARP (neuropathy, ataxia, retinitis pigmentosa), and Leigh syndrome. "
9.	Transfer RNA (tRNA)IBA 02/01/2002 - "Mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episode (MELAS) and myoclonic epilepsy and ragged-red fibers (MERRF) are rare disorders caused by point mutation of the tRNA gene of the mitochondrial genome. " 11/01/1995 - "We conclude that Ekbom's syndrome is a mitochondrial encephalomyopathy associated with the same heteroplasmic tRNA mutation as seen in myoclonus epilepsy with ragged-red fiber (MERRF) syndrome." 01/01/2014 - "Mitochondrial tRNA mutations manifest in a wide panoply of diseases related to cellular energetics, including COX deficiency (cytochrome C oxidase), mitochondrial myopathy, MERRF (Myoclonic Epilepsy with Ragged Red Fibers), and MELAS (mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes). " 03/01/2000 - "Using an assay that combines tRNA oxidation and circularization we have determined the relative amounts and states of aminoacylation of mutant and wild-type tRNAs in tissue samples from patients with MELAS syndrome (mito- chondrial myopathy, encephalopathy, lactic acidosis, stroke-like episodes) and MERRF syndrome (myoclonus epilepsy with ragged red fibers), respectively. " 04/01/2012 - "Myoclonic epilepsy with ragged-red fibers (MERRF) is a mitochondrial disease usually caused by point mutations in transfer RNA genes encoded by mitochondrial DNA. "
10.	lysine- tRNAIBA 01/01/2006 - "The eventual development of proximal weakness led to pathological and genetic testing which identified a A8344G mutation in the mitochondrial tRNA lysine gene, associated with MERRF (myoclonic epilepsy with ragged-red fibers). " 06/08/2004 - "This report shows that typical MERRF syndrome is not always associated with tRNA lysine mutations." 07/01/2012 - "The maternally inherited 8344 A>G mutation in the mitochondrial Lys tRNA is classically associated with the myoclonic epilepsy, ragged-red muscle fiber (MERRF) syndrome. " 04/01/2000 - "Multiple symmetric lipomatosis (MSL) has been related in some cases to the 8344 point mutation of the tRNA-lysine gene of the mitochondrial DNA, mainly in the context of families with classic myoclonic epilepsy with ragged-red fibers (MERRF) and exceptionally in patients with proximal myopathy as the only manifestation of mitochondrial disease. "

Therapies and Procedures

1.	Epidural Anesthesia 01/01/2005 - "We describe the successful administration of a combined general and epidural anesthesia with sevoflurane maintenance in a patient with myoclonic epilepsy with ragged red fibers (MERRF syndrome) scheduled for surgical treatment of bilateral clubfoot."