user: What are the symptoms of Myoclonic epilepsy with ragged red fibers ?

assistant: What are the signs and symptoms of Myoclonic epilepsy with ragged red fibers? Because muscle cells and nerve cells have especially high energy needs, muscular and neurological problems are common features of diseases that affect the mitochondria.  MERRF is a progressive multi-system syndrome with symptoms that begin during childhood, but onset may occur in adulthood. The rate of progression varies widely. Onset and extent of symptoms can differ widely from individual to individual and among affected siblings. The classic features of MERRF include: Myoclonus (brief, sudden, twitching muscle spasms)  the most characteristic symptom Epileptic seizures Ataxia (impaired coordination) Ragged-red fibers (a characteristic microscopic abnormality observed in muscle biopsy of patients with MERRF and other mitochondrial disorders) Additional symptoms may include: hearing loss, lactic acidosis (elevated lactic acid level in the blood), short stature, exercise intolerance, dementia, cardiac defects, eye abnormalities, and speech impairment. However, the exact symptoms aren't the same for everyone, because a person with mitochondrial disease can have a unique mixture of healthy and non-working mitochondria, with a unique distribution in the body. Despite their many potential effects, mitochondrial diseases sometimes cause little disability. Sometimes, a person has enough healthy mitochondria to compensate for the defective ones. The Human Phenotype Ontology provides the following list of signs and symptoms for Myoclonic epilepsy with ragged red fibers. If the information is available, the table below includes how often the symptom is seen in people with this condition. You can use the MedlinePlus Medical Dictionary to look up the definitions for these medical terms. Signs and Symptoms Approximate number of patients (when available) Abnormality of movement 90% EMG abnormality 90% Incoordination 90% Multiple lipomas 90% Myopathy 90% Sensorineural hearing impairment 90% Cognitive impairment 50% Short stature 50% Optic atrophy 7.5% Ataxia - Generalized myoclonic seizures - Increased serum lactate - Increased serum pyruvate - Mitochondrial inheritance - Muscle weakness - Myoclonus - Ragged-red muscle fibers - Seizures - Spasticity - The Human Phenotype Ontology (HPO) has collected information on how often a sign or symptom occurs in a condition. Much of this information comes from Orphanet, a European rare disease database. The frequency of a sign or symptom is usually listed as a rough estimate of the percentage of patients who have that feature. The frequency may also be listed as a fraction. The first number of the fraction is how many people had the symptom, and the second number is the total number of people who were examined in one study. For example, a frequency of 25/25 means that in a study of 25 people all patients were found to have that symptom. Because these frequencies are based on a specific study, the fractions may be different if another group of patients are examined. Sometimes, no information on frequency is available. In these cases, the sign or symptom may be rare or common.