- Muscle weakness (HP:0001324): Reduced strength of muscles. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:300605)
- Lower limb spasticity (HP:0002061): Spasticity (velocity-dependent increase in tonic stretch reflexes with increased muscle tone and hyperexcitable tendon reflexes) in the muscles of the lower limbs, hips, and pelvis. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:300605)
- Skeletal muscle atrophy (HP:0003202): The presence of skeletal muscular atrophy (which is also known as amyotrophy). Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:300605)
- Distal amyotrophy (HP:0003693): Muscular atrophy affecting muscles in the distal portions of the extremities. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:300605)
- Upper limb spasticity (HP:0006986). Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:300605)
- Amyotrophic lateral sclerosis (HP:0007354). Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:300605)
- Spastic diplegia (HP:0001264): Spasticity (neuromuscular hypertonia) primarily in the muscles of the legs, hips, and pelvis. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:300605)
- Hypertonia (HP:0001276): A condition in which there is increased muscle tone so that arms or legs, for example, are stiff and difficult to move. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:300605)
- Gait disturbance (HP:0001288): The term gait disturbance can refer to any disruption of the ability to walk. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:300605)
- Dystonia (HP:0001332): An abnormally increased muscular tone that causes fixed abnormal postures. There is a slow, intermittent twisting motion that leads to exaggerated turning and posture of the extremities and trunk. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:300605)
- Brisk reflexes (HP:0001348): Tendon reflexes that are noticeably more active than usual (conventionally denoted 3+ on clinical examination). Brisk reflexes may or may not indicate a neurological lesion. They are distinguished from hyperreflexia by the fact that hyerreflexia is characterized by hyperactive repeating (clonic) reflexes, which are considered to be always abnormal. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:300605)
- Abnormal speech pattern (HP:0002167): An abnormality in the sound (volume) or cadence (rate) of speech. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:300605)
- Distal muscle weakness (HP:0002460): Reduced strength of the musculature of the distal extremities. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:300605)
- Bulbar signs (HP:0002483). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:300605)
- Inability to walk (HP:0002540): Incapability to ambulate. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:300605)
- CNS hypomyelination (HP:0003429): Reduced amount of myelin in the central nervous system resulting from defective myelinogenesis. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:300605)
- Lower-limb joint contracture (HP:0005750): A limitation in the passive range of motion of a joint of the lower limb resulting from loss of elasticity in the periarticular tissues owing to structural changes of non-bony tissues, such as muscles, tendons, ligaments, joint capsules or skin. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:300605)
- Delayed ability to walk (HP:0031936): A failure to achieve the ability to walk at an appropriate developmental stage. Most children learn to walk in a series of stages, and learn to walk short distances independently between 12 and 15 months. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:300605)
- Arm dystonia (HP:0031960): A type of dystonia (abnormally increased muscular tone causing fixed abnormal postures) that affects muscles of the arms. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:300605)
- Muscle fiber atrophy (HP:0100295). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:300605)
- Upper-limb joint contracture (HP:0100360): A limitation in the passive range of motion of a joint of the upper limb resulting from loss of elasticity in the periarticular tissues owing to structural changes of non-bony tissues, such as muscles, tendons, ligaments, joint capsules or skin. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:300605)
- Urinary incontinence (HP:0000020): Loss of the ability to control the urinary bladder leading to involuntary urination. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:300605)
- Microcephaly (HP:0000252): Head circumference below 2 standard deviations below the mean for age and gender. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:300605)
- Supranuclear gaze palsy (HP:0000605): A supranuclear gaze palsy is an inability to look in a particular direction as a result of cerebral impairment. There is a loss of the voluntary aspect of eye movements, but, as the brainstem is still intact, all the reflex conjugate eye movements are normal. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:300605)
- Nystagmus (HP:0000639): Rhythmic, involuntary oscillations of one or both eyes related to abnormality in fixation, conjugate gaze, or vestibular mechanisms. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:300605)
- Atypical behavior (HP:0000708): Atypical behavior is an abnormality in a person's actions that can be controlled or modulated by the will of the individual. While abnormal behaviors can be difficult to control, they are distinct from other abnormal actions that cannot be affected by the individual's will. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:300605)
- Ataxia (HP:0001251): Ataxia refers to impaired coordination of voluntary muscle movement. Cerebellar ataxia refers to ataxia due to dysfunction of the cerebellum. This causes a variety of elementary neurological deficits including asynergy (lack of coordination between muscles, limbs and joints), dysmetria (lack of ability to judge distances that can lead to under- or overshoot in grasping movements), and dysdiadochokinesia (inability to perform rapid movements requiring antagonizing muscle groups to be switched on and off repeatedly). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:300605)
- Global developmental delay (HP:0001263): A delay in the achievement of motor or mental milestones in the domains of development of a child, including motor skills, speech and language, cognitive skills, and social and emotional skills. This term should only be used to describe children younger than five years of age. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:300605)
- Parkinsonism (HP:0001300): Characteristic neurologic anomaly resulting from degeneration of dopamine-generating cells in the substantia nigra, a region of the midbrain, characterized clinically by shaking, rigidity, slowness of movement and difficulty with walking and gait. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:300605)
- Abnormal cerebellum morphology (HP:0001317): Any structural abnormality of the cerebellum. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:300605)
- Dysphagia (HP:0002015): Difficulty in swallowing. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:300605)
- Chorea (HP:0002072): Chorea (Greek for 'dance') refers to widespread arrhythmic involuntary movements of a forcible, jerky and restless fashion. It is a random-appearing sequence of one or more discrete involuntary movements or movement fragments. Movements appear random because of variability in timing, duration or location. Each movement may have a distinct start and end. However, movements may be strung together and thus may appear to flow randomly from one muscle group to another. Chorea can involve the trunk, neck, face, tongue, and extremities. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:300605)
- Clonus (HP:0002169): A series of rhythmic and involuntary muscle contractions (at a frequency of about 5 to 7 Hz) that occur in response to an abruptly applied and sustained stretch. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:300605)
- Opisthotonus (HP:0002179): Opisthotonus is defined as a dramatic abnormal posture due to spastic contraction of the extensor muscles of the neck, trunk, and lower extremities that produces a severe backward arching from neck to heel. In most cases, the trunk is elevated off the ground by a few inches. It is usually sudden in onset and can be sustained or repetitive. It can be considered a variant of decerebrate posturing involving a hyperextension of the neck, back, and limbs. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:300605)
- Anarthria (HP:0002425): A defect in the motor ability that enables speech. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:300605)
- Axial dystonia (HP:0002530): A type of dystonia that affects the midline muscles, i.e., the chest, abdominal, and back muscles. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:300605)
- Retrocollis (HP:0002544): A form of torticollis in which the head is drawn back, either due to a permanent contractures of neck extensor muscles, or to a spasmodic contracture. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:300605)
- Head titubation (HP:0002599): A head tremor of moderate speed (3 to 4 Hz) in the anterior-posterior direction. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:300605)
- Scoliosis (HP:0002650): The presence of an abnormal lateral curvature of the spine. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:300605)
- Proximal muscle weakness (HP:0003701): A lack of strength of the proximal muscles. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:300605)
- Neck flexor weakness (HP:0003722): Weakness of the muscles involved in neck flexion (sternocleidomastoid, longus capitus, longus colli, and scalenus anterior). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:300605)
- Cachexia (HP:0004326): Severe weight loss, wasting of muscle, loss of appetite, and general debility related to a chronic disease. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:300605)
- Gastrostomy tube feeding in infancy (HP:0011471): Feeding problem necessitating gastrostomy tube feeding. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:300605)
- Oromandibular dystonia (HP:0012048): A kind of focal dystonia characterized by forceful contractions of the face, jaw, and/or tongue causing difficulty in opening and closing the mouth and often affecting chewing and speech. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:300605)
- Tip-toe gait (HP:0030051): An abnormal gait pattern characterized by the failure of the heel to contact the floor at the onset of stance during gait. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:300605)
- Cognitive impairment (HP:0100543): Abnormal cognition is characterized by deficits in thinking, reasoning, or remembering. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:300605)
These phenotypes are associated with the disease Juvenile amyotrophic lateral sclerosis (ORPHA:300605).