- Abnormal lower motor neuron morphology (HP:0002366): Any structural anomaly of the lower motor neuron. Evidence: PCS. (PMID:20110243)
- Juvenile onset (HP:0003621): Onset of signs or symptoms of disease between the age of 5 and 15 years. Evidence: PCS. Frequency: 10/23. (PMID:20110243)
- Babinski sign (HP:0003487): Upturning of the big toe (and sometimes fanning of the other toes) in response to stimulation of the sole of the foot. If the Babinski sign is present it can indicate damage to the corticospinal tract. Evidence: PCS. (PMID:20110243)
- Distal amyotrophy (HP:0003693): Muscular atrophy affecting muscles in the distal portions of the extremities. Evidence: PCS. Frequency: 23/23. (PMID:20110243)
- Bulbar signs (HP:0002483). Evidence: PCS. Frequency: 15/23. (PMID:20110243)
- Dysarthria (HP:0001260): Dysarthric speech is a general description referring to a neurological speech disorder characterized by poor articulation. Depending on the involved neurological structures, dysarthria may be further classified as spastic, flaccid, ataxic, hyperkinetic and hypokinetic, or mixed. Evidence: PCS. (PMID:20110243)
- Urinary incontinence (HP:0000020): Loss of the ability to control the urinary bladder leading to involuntary urination. Evidence: PCS. Frequency: 1/23. (PMID:20110243)
- Distal muscle weakness (HP:0002460): Reduced strength of the musculature of the distal extremities. Evidence: PCS. Frequency: 23/23. (PMID:20110243)
- Fasciculations (HP:0002380): 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: PCS. Frequency: 15/23. (PMID:20110243)
- Thin corpus callosum (HP:0033725): An abnormally thin corpus callous, due to atrophy, hypoplasia or agenesis. This term is intended to be used in situations where it is not known if thinning of the corpus callosum (for instance, as visualized by magnetic resonance tomography) is due to abnormal development (e.g. a leukodystrophy) or atrophy following normal development (e.g. neurodegeneration). Evidence: PCS. Frequency: 0/23. (PMID:20110243)
- Cognitive impairment (HP:0100543): Abnormal cognition is characterized by deficits in thinking, reasoning, or remembering. Evidence: PCS. Frequency: 0/23. (PMID:20110243)
- Young adult onset (HP:0011462): Onset of disease at the age of between 16 and 40 years. Evidence: PCS. Frequency: 13/23. (PMID:20110243)
- Amyotrophic lateral sclerosis (HP:0007354). Evidence: PCS. (PMID:20110243)
- Autosomal recessive inheritance (HP:0000007): A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in individuals with two pathogenic alleles, either homozygotes (two copies of the same mutant allele) or compound heterozygotes (whereby each copy of a gene has a distinct mutant allele). Evidence: PCS. (PMID:20110243)
- Abnormal pyramidal sign (HP:0007256): Functional neurological abnormalities related to dysfunction of the pyramidal tract. Evidence: PCS. Frequency: 23/23. (PMID:20110243)
- Respiratory insufficiency due to muscle weakness (HP:0002747). Evidence: PCS. Frequency: 2/23. (PMID:20110243)
- Spasticity (HP:0001257): A motor disorder characterized by a velocity-dependent increase in tonic stretch reflexes with increased muscle tone, exaggerated (hyperexcitable) tendon reflexes. Evidence: PCS. (PMID:20110243)
- Slowly progressive (HP:0003677): Applies to a disease manifestation that only slowly increases in scope or severity over the course of time. Evidence: PCS. (PMID:20110243)
- Abnormal cerebral white matter morphology (HP:0002500): An abnormality of the cerebral white matter. Evidence: PCS. Frequency: 0/23. (PMID:20110243)
- Hyperreflexia (HP:0001347): Hyperreflexia is the presence of hyperactive stretch reflexes of the muscles. Evidence: PCS. (PMID:20110243)
These phenotypes are associated with the disease amyotrophic lateral sclerosis type 5 (OMIM:602099).