- Distal lower limb muscle weakness (HP:0009053, a Human Phenotype Ontology term): Reduced strength of the distal musculature of the legs. Evidence: TAS. Frequency: Very frequent (HP:0040281, a Human Phenotype Ontology term). (ORPHA:276435)
- Hyporeflexia (HP:0001265, a Human Phenotype Ontology term): Reduction of neurologic reflexes such as the knee-jerk reaction. Evidence: TAS. Frequency: Frequent (HP:0040282, a Human Phenotype Ontology term). (ORPHA:276435)
- Areflexia (HP:0001284, a Human Phenotype Ontology term): Absence of neurologic reflexes such as the knee-jerk reaction. Evidence: TAS. Frequency: Frequent (HP:0040282, a Human Phenotype Ontology term). (ORPHA:276435)
- Gait disturbance (HP:0001288, a Human Phenotype Ontology term): The term gait disturbance can refer to any disruption of the ability to walk. Evidence: TAS. Frequency: Frequent (HP:0040282, a Human Phenotype Ontology term). (ORPHA:276435)
- Fasciculations (HP:0002380, a Human Phenotype Ontology term): Fasciculations are observed as small, local, involuntary muscle contractions (twitching) visible under the skin. Fasciculations result from increased irritability of an axon (which in turn is often a manifestation of disease of a motor neuron). This leads to sporadic discharges of all the muscle fibers controlled by the axon in isolation from other motor units. Evidence: TAS. Frequency: Frequent (HP:0040282, a Human Phenotype Ontology term). (ORPHA:276435)
- Elevated circulating creatine kinase activity (HP:0003236, a Human Phenotype Ontology term): The activity of creatine kinase in the blood circulation is above the upper limit of normal. Evidence: TAS. Frequency: Frequent (HP:0040282, a Human Phenotype Ontology term). (ORPHA:276435)
- EMG: neuropathic changes (HP:0003445, a Human Phenotype Ontology term): The presence of characteristic findings of denervation on electromyography (fibrillations, positive sharp waves, and giant motor unit potentials). Evidence: TAS. Frequency: Frequent (HP:0040282, a Human Phenotype Ontology term). (ORPHA:276435)
- Cold-induced muscle cramps (HP:0003449, a Human Phenotype Ontology term): Sudden and involuntary contractions of one or more muscles brought on by exposure to cold temperatures. Evidence: TAS. Frequency: Frequent (HP:0040282, a Human Phenotype Ontology term). (ORPHA:276435)
- Exercise-induced muscle cramps (HP:0003710, a Human Phenotype Ontology term): Sudden and involuntary contractions of one or more muscles brought on by physical exertion. Evidence: TAS. Frequency: Frequent (HP:0040282, a Human Phenotype Ontology term). (ORPHA:276435)
- Increased intramuscular fat (HP:0008985, a Human Phenotype Ontology term): An abnormal increase in the amount of intramuscular fat tissue. Evidence: TAS. Frequency: Frequent (HP:0040282, a Human Phenotype Ontology term). (ORPHA:276435)
- Proximal lower limb muscle weakness (HP:0008994, a Human Phenotype Ontology term): A lack of strength of the proximal muscles of the legs. Evidence: TAS. Frequency: Frequent (HP:0040282, a Human Phenotype Ontology term). (ORPHA:276435)
- Gastrocnemius myalgia (HP:0031921, a Human Phenotype Ontology term): Pain of the gastrocnemius muscle. Evidence: TAS. Frequency: Frequent (HP:0040282, a Human Phenotype Ontology term). (ORPHA:276435)
- Tongue fasciculations (HP:0001308, a Human Phenotype Ontology term): Fasciculations or fibrillation affecting the tongue muscle. Evidence: TAS. Frequency: Occasional (HP:0040283, a Human Phenotype Ontology term). (ORPHA:276435)
- Tremor (HP:0001337, a Human Phenotype Ontology term): An unintentional, oscillating to-and-fro muscle movement about a joint axis. Evidence: TAS. Frequency: Occasional (HP:0040283, a Human Phenotype Ontology term). (ORPHA:276435)
- Dysphagia (HP:0002015, a Human Phenotype Ontology term): Difficulty in swallowing. Evidence: TAS. Frequency: Occasional (HP:0040283, a Human Phenotype Ontology term). (ORPHA:276435)
- Ragged-red muscle fibers (HP:0003200, a Human Phenotype Ontology term): 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. Frequency: Occasional (HP:0040283, a Human Phenotype Ontology term). (ORPHA:276435)
- EMG: myopathic abnormalities (HP:0003458, a Human Phenotype Ontology term): The presence of abnormal electromyographic patterns indicative of myopathy, such as small-short polyphasic motor unit potentials. Evidence: TAS. Frequency: Occasional (HP:0040283, a Human Phenotype Ontology term). (ORPHA:276435)
- Rimmed vacuoles (HP:0003805, a Human Phenotype Ontology term): Presence of abnormal vacuoles (membrane-bound organelles) in the sarcolemma. On histological staining with hematoxylin and eosin, rimmed vacuoles are popcorn-like clear vacuoles with a densely blue rim. The vacuoles are often associated with cytoplasmic and occasionally intranuclear eosinophilic inclusions. Evidence: TAS. Frequency: Occasional (HP:0040283, a Human Phenotype Ontology term). (ORPHA:276435)
- Impaired distal vibration sensation (HP:0006886, a Human Phenotype Ontology term): A decrease in the ability to perceive vibration in the distal portions of the limbs. Evidence: TAS. Frequency: Occasional (HP:0040283, a Human Phenotype Ontology term). (ORPHA:276435)
- Intrinsic hand muscle atrophy (HP:0008954, a Human Phenotype Ontology term): Atrophy of the intrinsic muscle groups of the hand, comprising the thenar and hypothenar muscles; the interossei muscles; and the lumbrical muscles. Evidence: TAS. Frequency: Occasional (HP:0040283, a Human Phenotype Ontology term). (ORPHA:276435)
- Proximal upper limb muscle weakness (HP:0008997, a Human Phenotype Ontology term): A lack of strength of the proximal muscles of the arms. Evidence: TAS. Frequency: Occasional (HP:0040283, a Human Phenotype Ontology term). (ORPHA:276435)
- Abnormal sensory nerve conduction velocity (HP:0040132, a Human Phenotype Ontology term). Evidence: TAS. Frequency: Occasional (HP:0040283, a Human Phenotype Ontology term). (ORPHA:276435)
- Abnormality of the respiratory system (HP:0002086, a Human Phenotype Ontology term): An abnormality of the respiratory system, which include the airways, lungs, and the respiratory muscles. Evidence: TAS. Frequency: Very rare (HP:0040284, a Human Phenotype Ontology term). (ORPHA:276435)
- Bulbar signs (HP:0002483, a Human Phenotype Ontology term). Evidence: TAS. Frequency: Very rare (HP:0040284, a Human Phenotype Ontology term). (ORPHA:276435)
- Inability to walk (HP:0002540, a Human Phenotype Ontology term): Incapability to ambulate. Evidence: TAS. Frequency: Very rare (HP:0040284, a Human Phenotype Ontology term). (ORPHA:276435)
These phenotypes are associated with the disease Lower motor neuron syndrome with late-adult onset (ORPHA:276435, an Orphanet rare-disease identifier).
The following phenotypes are NOT associated with this disease:
- Upper motor neuron dysfunction (HP:0002493, a Human Phenotype Ontology term): A functional anomaly of the upper motor neuron. The upper motor neurons are neurons of the primary motor cortex which project to the brainstem and spinal chord via the corticonuclear, corticobulbar and corticospinal (pyramidal) tracts. They are involved in control of voluntary movements. Dysfunction leads to weakness, impairment of fine motor movements, spasticity, hyperreflexia and abnormal pyramidal signs. Evidence: TAS. (ORPHA:276435)