- Abnormal lower motor neuron morphology (HP:0002366): Any structural anomaly of the lower motor neuron. Evidence: TAS. (OMIM:616439)
- Hyporeflexia (HP:0001265): Reduction of neurologic reflexes such as the knee-jerk reaction. Evidence: TAS. (OMIM:616439)
- Mutism (HP:0002300): Complete lack of speech or verbal communication in a person despite attempts to engage in conversation. Mutism as a phenomena assumes the individual has previous capacity for speech and in the pediatric population it assumes that the person is past the age of typical language development. Evidence: TAS. (OMIM:616439)
- Skeletal muscle atrophy (HP:0003202): The presence of skeletal muscular atrophy (which is also known as amyotrophy). Evidence: TAS. (OMIM:616439)
- Dysphagia (HP:0002015): Difficulty in swallowing. Evidence: TAS. (OMIM:616439)
- Progressive (HP:0003676): Applies to a disease manifestation that increases in scope or severity over the course of time, i.e., that worsens with age. Evidence: TAS. (OMIM:616439)
- Language impairment (HP:0002463): Language impairment is a deficit in comprehension or production of language that includes reduced vocabulary, limited sentence structure, or impairments in written or spoken communication. Language abilities are substantially and quantifiably below age expectations. Evidence: TAS. (OMIM:616439)
- Frontotemporal dementia (HP:0002145): A dementia associated with degeneration of the frontotemporal lobe and clinically associated with personality and behavioral changes such as disinhibition, apathy, and lack of insight. The hallmark feature of frontotemporal dementia is the presentation with focal syndromes such as progressive language dysfunction, or aphasia, or behavioral changes characteristic of frontal lobe disorders. Evidence: TAS. (OMIM:616439)
- Bulbar palsy (HP:0001283): Bulbar weakness (or bulbar palsy) refers to bilateral impairment of function of the lower cranial nerves IX, X, XI and XII, which occurs due to lower motor neuron lesion either at nuclear or fascicular level in the medulla or from bilateral lesions of the lower cranial nerves outside the brain-stem. Bulbar weakness is often associated with difficulty in chewing, weakness of the facial muscles, dysarthria, palatal weakness and regurgitation of fluids, dysphagia, and dysphonia. Evidence: TAS. (OMIM:616439)
- Cerebral cortical atrophy (HP:0002120): Atrophy of the cortex of the cerebrum. Evidence: TAS. (OMIM:616439)
- 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: TAS. (OMIM:616439)
- Adult onset (HP:0003581): Onset of disease manifestations in adulthood, defined here as at the age of 16 years or later. Evidence: PCS. (PMID:25803835)
- 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: TAS. (OMIM:616439)
- Amyotrophic lateral sclerosis (HP:0007354). Evidence: TAS. (OMIM:616439)
- Disinhibition (HP:0000734): Reduced ability to control, or a failure to resist a temptation, urge, or impulse. Examples include disregard for social conventions, general impulsivity, and poor risk assessment. Evidence: TAS. (OMIM:616439)
- Apathy (HP:0000741): Apathy is a quantitative reduction of interest, motivation and the initiation and persistence of goal-directed behavior, where often the accompanying emotions, thoughts, and social interactions are also diminished. The individual is typically non-reactive to provocations, positive or negative, and appears to not care. Distinguished from lethargy which involves lack of physical or mental energy. Evidence: TAS. (OMIM:616439)
- Muscle weakness (HP:0001324): Reduced strength of muscles. Evidence: TAS. (OMIM:616439)
- Personality changes (HP:0000751): An abnormal shift in patterns of thinking, acting, or feeling. Evidence: TAS. (OMIM:616439)
- Autosomal dominant inheritance (HP:0000006): 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 heterozygotes. In the context of medical genetics, an autosomal dominant disorder is caused when a single copy of the mutant allele is present. Males and females are affected equally, and can both transmit the disorder with a risk of 50% for each child of inheriting the mutant allele. Evidence: PCS. (PMID:25803835)
- Hyperreflexia (HP:0001347): Hyperreflexia is the presence of hyperactive stretch reflexes of the muscles. Evidence: TAS. (OMIM:616439)
These phenotypes are associated with the disease frontotemporal dementia and/or amyotrophic lateral sclerosis 4 (OMIM:616439).