A number of human diseases are caused by inherited mitochondrial DNA mutations. Two of these diseases, MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes) and MERRF (myoclonic epilepsy and ragged-red fibres), are commonly caused by point mutations to tRNA genes encoded by mitochondrial DNA. Here we report on how these mutations affect mitochondrial function ...

Myoclonus epilepsy associated with ragged-red fibers (MERRF) is a maternally inherited mitochondrial disease affecting neuromuscular functions. Mt.8344A>G mutation in mitochondrial DNA (mtDNA) is the most common cause of MERRF syndrome and has been linked to an increase in reactive oxygen species (ROS) level and oxidative stress, as well as impaired mitochondrial bioenergetics. Here, we tested w...

BACKGROUND Myoclonic epilepsy with ragged-red fibres (MERRF) and mitochondrial encephalopathy, lactic acidosis and stroke-like episodes (MELAS) are established phenotypes of mitochondrial encephalomyopathy. The m.8356T>C transition in the mitochondrial tRNA(Lys) gene is a pathogenic mutations of MERRF. The m.3243A>G transition in the mitochondrial tRNA(Leu) gene is detected in most MELAS patien...

Background: Myoclonic epilepsy with ragged-red fi bers (MERRF) is a type of mitochondrial encephalomyopathy, clinical experience with the antiepileptic treatment for myoclonus in MERRF is still limited. Myoclonus appears to be intractable, and some antiepileptic drugs may change the blood lactate level. Objective: In this study, we report on two patients, a girl and her mother, both with MERRF ...

Myoclonus epilepsy with ragged-red fibers (MERRFs), an inherited mitochondrial disorder, has characteristic morphological changes of ragged-red fibers (RRFs) in muscle biopsy, in the absence of which mitochondrial etiology is usually not considered in patients with phenotypes suggestive of MERRF. In these circumstances, MERRF can only be diagnosed using genetic analyses. The symptoms, pathologi...

MERRF syndrome (or Myoclonic Epilepsy with Ragged Red Fibers) is a mitochondrial disease maternally-inherited. In this progressive disorder, status epilepticus is common and highly resistant to treatment including generalized anesthesia. We report two cases with Merrf syndrome (sister and brother), presented with status epilepticus refractory even to Thiopental, Propofol and Midazolam. In the s...

Myoclonic epilepsy with red ragged fibres (MERRF) is a rare mitochondrial disorder presenting with progressive myoclonus, epilepsy, and cognitive decline. Here, the authors present a case of a 29-year-old lady presenting with myoclonus and describe the subsequent investigations that led to a diagnosis of MERRF. In addition, we examine her cognitive decline over a 9-year period, demonstrating a ...

MERRF is characterized by muscle twitches (myoclonus), weakness (myopathy), and progressive stiffness (spasticity). When the muscle cells of affected individuals are stained and viewed under a microscope, these cells usually appear abnormal. These abnormal muscle cells are called ragged-red fibers. Other features of MERRF include recurrent seizures (epilepsy), difficulty coordinating movements ...

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. To understand the pathogenetic mechanism of MELAS and MERRF, we studied four patients. Serially sectioned frozen muscle specimens with a battery of histochemical stai...