- Periodic hypokalemic paresis (HP:0008153, a Human Phenotype Ontology term): Episodes of muscle weakness associated with reduced levels of potassium in the blood. Evidence: TAS. Frequency: Obligate (HP:0040280, a Human Phenotype Ontology term). (ORPHA:681)
- Episodic hypokalemia (HP:0012726, a Human Phenotype Ontology term): An abnormally decreased potassium concentration in the blood occurring periodically with a return to normal between the episodes. Evidence: TAS. Frequency: Obligate (HP:0040280, a Human Phenotype Ontology term). (ORPHA:681)
- EMG abnormality (HP:0003457, a Human Phenotype Ontology term): Abnormal results of investigations using electromyography (EMG). Evidence: TAS. Frequency: Very frequent (HP:0040281, a Human Phenotype Ontology term). (ORPHA:681)
- Paralysis (HP:0003470, a Human Phenotype Ontology term): Paralysis of voluntary muscles means loss of contraction due to interruption of one or more motor pathways from the brain to the muscle fibers. Although the word paralysis is often used interchangeably to mean either complete or partial loss of muscle strength, it is preferable to use paralysis or plegia for complete or severe loss of muscle strength, and paresis for partial or slight loss. Motor paralysis results from deficits of the upper motor neurons (corticospinal, corticobulbar, or subcorticospinal). Motor paralysis is often accompanied by an impairment in the facility of movement. Evidence: TAS. Frequency: Very frequent (HP:0040281, a Human Phenotype Ontology term). (ORPHA:681)
- Episodic flaccid weakness (HP:0003752, a Human Phenotype Ontology term): Recurrent episodes of muscle flaccidity, a type of paralysis in which a muscle becomes soft and yields to passive stretching. Evidence: TAS. Frequency: Very frequent (HP:0040281, a Human Phenotype Ontology term). (ORPHA:681)
- Abnormal muscle fiber morphology (HP:0004303, a Human Phenotype Ontology term): Any abnormality of the skeletal muscle cell. Muscle fibers are subdivided into two types. Type I fibers are fatigue-resistant and rich in oxidative enzymes (they stain light with the myosin ATPase reaction), and type II fibers are fast-contracting, fatigue-prone, and rich in glycolytic enzymes (these fibers stain darkly). Normal muscle tissue has a random distribution of type I and type II fibers. Evidence: TAS. Frequency: Very frequent (HP:0040281, a Human Phenotype Ontology term). (ORPHA:681)
- Mildly elevated creatine kinase (HP:0008180, a Human Phenotype Ontology term). Evidence: TAS. Frequency: Very frequent (HP:0040281, a Human Phenotype Ontology term). (ORPHA:681)
- Increased intramyocellular lipid droplets (HP:0012240, a Human Phenotype Ontology term): An abnormal increase in intracellular lipid droplets In a muscle. The number and size of these drops can increase with somd disorders of lipid metabolism affecting muscle. See PMID 20691590 for histological images. Evidence: TAS. Frequency: Very frequent (HP:0040281, a Human Phenotype Ontology term). (ORPHA:681)
- Diminished deep tendon reflex (HP:0001315, a Human Phenotype Ontology term): A reduction (hyporeflexia) or complete absence (areflexia) of the involuntary muscle contraction normally elicited by a reflex stimulus, such as tapping a deep tendon. Evidence: TAS. Frequency: Frequent (HP:0040282, a Human Phenotype Ontology term). (ORPHA:681)
- Exercise-induced muscle fatigue (HP:0009020, a Human Phenotype Ontology term): An abnormally increased tendency towards muscle fatigue induced by physical exercise. Evidence: TAS. Frequency: Frequent (HP:0040282, a Human Phenotype Ontology term). (ORPHA:681)
- Postprandial hyperglycemia (HP:0011998, a Human Phenotype Ontology term): An increased concentration of glucose in the blood following a meal. Evidence: TAS. Frequency: Frequent (HP:0040282, a Human Phenotype Ontology term). (ORPHA:681)
- Respiratory insufficiency due to muscle weakness (HP:0002747, a Human Phenotype Ontology term). Evidence: TAS. Frequency: Occasional (HP:0040283, a Human Phenotype Ontology term). (ORPHA:681)
- Muscle spasm (HP:0003394, a Human Phenotype Ontology term): Sudden and involuntary contractions of one or more muscles. Evidence: TAS. Frequency: Occasional (HP:0040283, a Human Phenotype Ontology term). (ORPHA:681)
- Late-onset proximal muscle weakness (HP:0003694, a Human Phenotype Ontology term): Lack of strength of the proximal musculature occurring late in the clinical course. Evidence: TAS. Frequency: Occasional (HP:0040283, a Human Phenotype Ontology term). (ORPHA:681)
- Arrhythmia (HP:0011675, a Human Phenotype Ontology term): 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. Frequency: Occasional (HP:0040283, a Human Phenotype Ontology term). (ORPHA:681)
- Pain (HP:0012531, a Human Phenotype Ontology term): An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage. Evidence: TAS. Frequency: Occasional (HP:0040283, a Human Phenotype Ontology term). (ORPHA:681)
- Fatty replacement of skeletal muscle (HP:0012548, a Human Phenotype Ontology term): Muscle fibers degeneration resulting in fatty replacement of skeletal muscle fibers. Evidence: TAS. Frequency: Occasional (HP:0040283, a Human Phenotype Ontology term). (ORPHA:681)
- Respiratory paralysis (HP:0002203, a Human Phenotype Ontology term): Inability to move the muscles of respiration. Evidence: TAS. Frequency: Very rare (HP:0040284, a Human Phenotype Ontology term). (ORPHA:681)
- Adrenocortical adenoma (HP:0008256, a Human Phenotype Ontology term): Adrenocortical adenomas are benign tumors of the adrenal cortex. Evidence: TAS. Frequency: Very rare (HP:0040284, a Human Phenotype Ontology term). (ORPHA:681)
- Fatigable weakness of respiratory muscles (HP:0030196, a Human Phenotype Ontology term): A type of weakness of the muscles involved in breathing (respiration) that occurs after a muscle group is used and lessens if the muscle group has some rest. That is, there is diminution of strength with repetitive muscle actions. Evidence: TAS. Frequency: Very rare (HP:0040284, a Human Phenotype Ontology term). (ORPHA:681)
These phenotypes are associated with the disease Hypokalemic periodic paralysis (ORPHA:681, an Orphanet rare-disease identifier).
The following phenotypes are NOT associated with this disease:
- Myotonia (HP:0002486, a Human Phenotype Ontology term): An involuntary and painless delay in the relaxation of skeletal muscle following contraction or electrical stimulation. Evidence: TAS. (ORPHA:681)
- Impaired myocardial contractility (HP:0006670, a Human Phenotype Ontology term). Evidence: TAS. (ORPHA:681)