Phenotypes associated with the disease MELAS syndrome (OMIM:540000):
- Encephalopathy (HP:0001298): Encephalopathy is a term that means brain disease, damage, or malfunction. In general, encephalopathy is manifested by an altered mental state. Evidence: IEA. (OMIM:540000)
- Bilateral tonic-clonic seizure (HP:0002069): A bilateral tonic-clonic seizure is a seizure defined by a tonic (bilateral increased tone, lasting seconds to minutes) and then a clonic (bilateral sustained rhythmic jerking) phase. Evidence: TAS. (OMIM:540000)
- Myopathy (HP:0003198): A disorder of muscle unrelated to impairment of innervation or neuromuscular junction. Evidence: IEA. (OMIM:540000)
- Arrhythmia (HP:0011675): Any cardiac rhythm other than the normal sinus rhythm. Such a rhythm may be either of sinus or ectopic origin and either regular or irregular. An arrhythmia may be due to a disturbance in impulse formation or conduction or both. Evidence: TAS. (OMIM:540000)
- Diabetes mellitus (HP:0000819): A group of abnormalities characterized by hyperglycemia and glucose intolerance. Evidence: TAS. (OMIM:540000)
- Hemianopia (HP:0012377): Partial or complete loss of vision in one half of the visual field of one or both eyes. Evidence: TAS. (OMIM:540000)
- Growth abnormality (HP:0001507). Evidence: IEA. (OMIM:540000)
- Cerebral visual impairment (HP:0100704): A form of loss of vision caused by damage to the visual cortex rather than a defect in the eye. Evidence: IEA. (OMIM:540000)
- Variable expressivity (HP:0003828): A variable severity of phenotypic features. Evidence: TAS. (OMIM:540000)
- Developmental cataract (HP:0000519): A cataract that occurs congenitally as the result of a developmental defect, in contrast to the majority of cataracts that occur in adulthood as the result of degenerative changes of the lens. Evidence: IEA. (OMIM:540000)
- Mitochondrial inheritance (HP:0001427): A mode of inheritance that is observed for traits related to a gene encoded on the mitochondrial genome. Because the mitochondrial genome is essentially always maternally inherited, a mitochondrial condition can only be transmitted by females, although the condition can affect both sexes. The proportion of mutant mitochondria can vary (heteroplasmy). Evidence: IEA. (OMIM:540000)
- Hemiparesis (HP:0001269): Loss of strength in the arm, leg, and sometimes face on one side of the body. Hemiplegia refers to a complete loss of strength, whereas hemiparesis refers to an incomplete loss of strength. Evidence: IEA. (OMIM:540000)
- Lactic acidosis (HP:0003128): An abnormal buildup of lactic acid in the body, leading to acidification of the blood and other bodily fluids. Evidence: TAS. (OMIM:540000)
- Ragged-red muscle fibers (HP:0003200): An abnormal appearance of muscle fibers observed on muscle biopsy. Ragged red fibers can be visualized with Gomori trichrome staining as irregular and intensely red subsarcolemmal zones, whereas the normal myofibrils are green. The margins of affect fibers appear red and ragged. The ragged-red is due to the accumulation of abnormal mitochondria below the plasma membrane of the muscle fiber, leading to the appearance of a red rim and speckled sarcoplasm. Evidence: TAS. (OMIM:540000)
- Bilateral sensorineural hearing impairment (HP:0008619): A form of sensorineural hearing impairment that affects both ears. Evidence: IEA. (OMIM:540000)
- Migraine (HP:0002076): Migraine is a chronic neurological disorder characterized by episodic attacks of headache and associated symptoms. Evidence: IEA. (OMIM:540000)
- Episodic vomiting (HP:0002572): Paroxysmal, recurrent episodes of vomiting. Evidence: IEA. (OMIM:540000)
- Abnormal left ventricular function (HP:0005162): Inability of the left ventricle to perform its normal physiologic function. Failure is either due to an inability to contract the left ventricle or the inability to relax completely and fill with blood during diastole. Evidence: IEA. (OMIM:540000)
- Progressive sensorineural hearing impairment (HP:0000408): A progressive form of sensorineural hearing impairment. Evidence: IEA. (OMIM:540000)
- Dementia (HP:0000726): A loss of global cognitive ability of sufficient amount to interfere with normal social or occupational function. Dementia represents a loss of previously present cognitive abilities, generally in adults, and can affect memory, thinking, language, judgment, and behavior. Evidence: IEA. (OMIM:540000)
- Wolff-Parkinson-White syndrome (HP:0001716): A disorder of the cardiac conduction system of the heart characterized by ventricular preexcitation due to the presence of an abnormal accessory atrioventricular electrical conduction pathway. Evidence: TAS. (OMIM:540000)
- Hypertension (HP:0000822): The presence of chronic increased pressure in the systemic arterial system. Evidence: TAS. (OMIM:540000)
- Ophthalmoplegia (HP:0000602): Paralysis of one or more extraocular muscles that are responsible for eye movements. Evidence: TAS. (OMIM:540000)
- Congestive heart failure (HP:0001635): The presence of an abnormality of cardiac function that is responsible for the failure of the heart to pump blood at a rate that is commensurate with the needs of the tissues or a state in which abnormally elevated filling pressures are required for the heart to do so. Heart failure is frequently related to a defect in myocardial contraction. Evidence: TAS. (OMIM:540000)
- Left ventricular hypertrophy (HP:0001712): Enlargement or increased size of the heart left ventricle. Evidence: TAS. (OMIM:540000)
- Mitochondrial myopathy (HP:0003737): A type of myopathy associated with mitochondrial disease and characterized by findings on biopsy such as ragged red muscle fibers. Evidence: TAS. (OMIM:540000)
- Stroke-like episode (HP:0002401): No consensus exists on what a stroke-like episode is, but these episodes can be functionally defined as a new neurological deficit, occurring with or without the context of seizures, which last longer than 24 hours. Evidence: IEA. (OMIM:540000)