What is myoclonic epilepsy with ragged red fibers?
Myoclonic epilepsy with ragged red fibers (MERRF) is a multisystem disorder characterized by myoclonus, which is often the first symptom, followed by generalized epilepsy, ataxia , weakness, and dementia . Symptoms usually first appear in childhood or adolescence after normal early development.
What causes ragged red fibers?
MERRF syndrome is caused by mutations in mtDNA and is inherited from the mother. MERRF syndrome was first reported in 1973 when a family was described with muscle jerks (myoclonus), seizures and abnormal muscle cells showing characteristic ragged red fibers (RRF).
What mitochondrial proteins are affected in MERRF myoclonic epilepsy and ragged red fiber syndrome?
MERRF occurs due to genetic mutations in the mitochondrial DNA (mtDNA) with A8344G mutation in the tRNA (Lys) gene being the most common and present in more than three-fourth of the patients. The pathognomonic red-ragged muscle fibers are seen on muscle biopsy.
Are myoclonic jerks epilepsy?
This type of seizure causes quick jerking movements. Myoclonic seizures often happen in everyday life. This includes hiccups and a sudden jerk while falling asleep. The condition is not epilepsy unless there are more than two seizures happening repeatedly over time.
What are red fibers?
Slow twitch fibers are also known as red fibers since they have a high oxygen content. In order to store oxygen in muscle cells the oxygen transporter myoglobin is needed. As this protein has a red colour, the muscle fibers appear also reddish.
What syndromes are associated with myoclonic seizures?
Myoclonic jerks or seizures are associated with many acquired conditions. The most common is the syndrome of postanoxic myoclonus, also termed the Lance-Adams syndrome. Myoclonus may also be associated with head injury, stroke, tumors, encephalitis, Creutzfeldt-Jakob dis- ease, and uremia.
What does MERRF mean?
MERRF syndrome (or myoclonic epilepsy with ragged red fibers) is a mitochondrial disease. It is extremely rare, and has varying degrees of expressivity owing to heteroplasmy. MERRF syndrome affects different parts of the body, particularly the muscles and nervous system.
How does MERRF affect cellular respiration?
The most common mutation associated with MERRF syndrome, m. 8344A > G in the gene MT-TK, which encodes transfer RNALysine, affects the translation of all mitochondrial DNA encoded proteins. This impairs the assembly of the electron transport chain complexes leading to decreased mitochondrial respiratory function.
Are myoclonic seizures serious?
Myoclonic seizures are a symptom found in a number of progressive seizure disorders. They are typically rare. Some, like EPM1, cause severe symptoms in childhood but overall life expectancy is normal. Others, such as Lafora disease, will prove fatal within 10 years.
Where is red fibers found?
Red muscles are named so because they are dense with capillaries and are rich in myoglobin and mitochondria – which gives it a characteristic red appearance….
| Difference Between White Muscle and Red Muscle Fibers | |
|---|---|
| Red Muscle Fibers | White Muscle Fibers |
| Rate of Contractions | |
| Slow rate of contraction | Fast rate of contraction |
What are red muscle fibers used for?
Red muscles have slow-twitch fibers which can contract slowly for a long period of time without fatigue. They are used during aerobic exercises and as such, rely on lots of oxygen to generate energy.