- Cerebellar atrophy (HP:0001272): Cerebellar atrophy is defined as a cerebellum with initially normal structures, in a posterior fossa with normal size, which displays enlarged fissures (interfolial spaces) in comparison to the foliae secondary to loss of tissue. Cerebellar atrophy implies irreversible loss of tissue and result from an ongoing progressive disease until a final stage is reached or a single injury, e.g. an intoxication or infectious event. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:35069)
- Psychomotor deterioration (HP:0002361): Loss of previously present mental and motor abilities. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:35069)
- Developmental regression (HP:0002376): Loss of developmental skills, as manifested by loss of developmental milestones. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:35069)
- Optic atrophy (HP:0000648): Atrophy of the optic nerve. Optic atrophy results from the death of the retinal ganglion cell axons that comprise the optic nerve and manifesting as a pale optic nerve on fundoscopy. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:35069)
- Abnormality of visual evoked potentials (HP:0000649): An anomaly of visually evoked potentials (VEP), which are electrical potentials, initiated by brief visual stimuli, which are recorded from the scalp overlying the visual cortex. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:35069)
- 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: Frequent (HP:0040282). (ORPHA:35069)
- Mental deterioration (HP:0001268): Loss of previously present mental abilities, generally in adults. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:35069)
- Spastic tetraparesis (HP:0001285): Spastic weakness affecting all four limbs. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:35069)
- Hyperreflexia (HP:0001347): Hyperreflexia is the presence of hyperactive stretch reflexes of the muscles. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:35069)
- Progressive spasticity (HP:0002191): Spasticity that increases in degree with time. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:35069)
- Unsteady gait (HP:0002317). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:35069)
- Eye of the tiger anomaly of globus pallidus (HP:0002454): The presence, on T2-weighted magnetic resonance imaging, of markedly low signal intensity of the globus pallidus that surrounds a central region of high signal intensity in the anteromedial globus pallidus, producing an eye-of-the-tiger appearance. The sign is thought to represent iron accumulation in the globus pallidus. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:35069)
- Bulbar signs (HP:0002483). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:35069)
- Abnormal cerebral white matter morphology (HP:0002500): An abnormality of the cerebral white matter. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:35069)
- Abnormality of peripheral nerve conduction (HP:0003134): An abnormality of the conduction of electrical impulses by peripheral (motor or sensory) nerves. This finding is elicited by a nerve conduction study (NCS). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:35069)
- Diffuse axonal swelling (HP:0003405). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:35069)
- EMG: chronic denervation signs (HP:0003444): Evidence of chronic denervation on electromyography. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:35069)
- Peripheral axonal neuropathy (HP:0003477): An abnormality characterized by disruption of the normal functioning of peripheral axons. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:35069)
- Sensorimotor neuropathy (HP:0007141). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:35069)
- Abnormal pyramidal sign (HP:0007256): Functional neurological abnormalities related to dysfunction of the pyramidal tract. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:35069)
- Axial hypotonia (HP:0008936): Muscular hypotonia (abnormally low muscle tone) affecting the musculature of the trunk. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:35069)
- Peripheral neuropathy (HP:0009830): Peripheral neuropathy is a general term for any disorder of the peripheral nervous system. The main clinical features used to classify peripheral neuropathy are distribution, type (mainly demyelinating versus mainly axonal), duration, and course. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:35069)
- Iron accumulation in brain (HP:0012675): An abnormal build up of iron (Fe) in brain tissue. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:35069)
- Cerebellar gliosis (HP:0012698): Focal proliferation of glial cells in the cerebellum. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:35069)
- Increased circulating lactate dehydrogenase concentration (HP:0025435): An elevated level of the enzyme lactate dehydrogenase in the blood circulation. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:35069)
- Strabismus (HP:0000486): A misalignment of the eyes so that the visual axes deviate from bifoveal fixation. The classification of strabismus may be based on a number of features including the relative position of the eyes, whether the deviation is latent or manifest, intermittent or constant, concomitant or otherwise and according to the age of onset and the relevance of any associated refractive error. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:35069)
- Blindness (HP:0000618): Blindness is the condition of lacking visual perception defined as a profound reduction in visual perception. On the 6m visual acuity scale, blindness is defined as less than 3/60. On the 20ft visual acuity scale, blindness is defined as less than 20/400. On the decimal visual acuity scale, blindness is defined as less than 0.05. Blindness is typically characterized by a visual field of no greater than 10 degrees in radius around central fixation. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:35069)
- 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:35069)
- 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:35069)
- Emotional lability (HP:0000712): Unstable emotional experiences and frequent mood changes; emotions that are easily aroused, intense, and/or disproportionate to events and circumstances. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:35069)
- Autistic behavior (HP:0000729): Persistent deficits in social interaction and communication and interaction as well as a markedly restricted repertoire of activity and interest as well as repetitive patterns of behavior. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:35069)
- Short attention span (HP:0000736): Reduced attention span characterized by distractibility and impulsivity. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:35069)
- Delayed speech and language development (HP:0000750): A degree of language development that is significantly below the norm for a child of a specified age. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:35069)
- Hyperactivity (HP:0000752): Hyperactivity is a condition characterized by constant and unusually high levels of activity, even in situations where it is deemed inappropriate. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:35069)
- 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: TAS. Frequency: Occasional (HP:0040283). (ORPHA:35069)
- 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. Frequency: Occasional (HP:0040283). (ORPHA:35069)
- Gait disturbance (HP:0001288): The term gait disturbance can refer to any disruption of the ability to walk. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:35069)
- 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: Occasional (HP:0040283). (ORPHA:35069)
- Flexion contracture (HP:0001371): A flexion contracture is a bent (flexed) joint that cannot be straightened actively or passively. It is thus a chronic loss of joint motion due to structural changes in muscle, tendons, ligaments, or skin that prevents normal movement of joints. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:35069)
- Constipation (HP:0002019): Infrequent or difficult evacuation of feces. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:35069)
- Drooling (HP:0002307): Habitual flow of saliva out of the mouth. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:35069)
- Temperature instability (HP:0005968): Disordered thermoregulation characterized by an impaired ability to maintain a balance between heat production and heat loss, with resulting instability of body temperature. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:35069)
- Aspiration pneumonia (HP:0011951): Pneumonia due to the aspiration (breathing in) of food, liquid, or gastric contents into the upper respiratory tract. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:35069)
- Pendular nystagmus (HP:0012043): Rhythmic, involuntary sinusoidal oscillations of one or both eyes. The waveform of pendular nystagmus may occur in any direction. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:35069)
- Abnormal autonomic nervous system physiology (HP:0012332): A functional abnormality of the autonomic nervous system. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:35069)
- Impulsivity (HP:0100710): Acting on the spur of the moment or on a momentary basis without consideration of outcomes; having difficulty establishing or following plans; experiencing a sense of urgency and engaging in behavior that is uninhibited, cannot be inhibited, and is uncontrolled. The possibility of repression is inconceivable. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:35069)
- Seizure (HP:0001250): A seizure is an intermittent abnormality of nervous system physiology characterized by a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain. Evidence: TAS. Frequency: Very rare (HP:0040284). (ORPHA:35069)
- Apneic episodes in infancy (HP:0005949): Recurrent episodes of apnea occurring during infancy. Evidence: TAS. Frequency: Very rare (HP:0040284). (ORPHA:35069)
- Downbeat nystagmus (HP:0010545): Downbeat nystagmus is a type of fixation nystagmus with the fast phase beating in a downward direction. It generally increases when looking to the side and down and when lying prone. Evidence: TAS. Frequency: Very rare (HP:0040284). (ORPHA:35069)
- Upgaze palsy (HP:0025331): A limitation of the ability to direct one's gaze above the horizontal meridian. Evidence: TAS. Frequency: Very rare (HP:0040284). (ORPHA:35069)
- Choking episodes (HP:0030842): Incidents in which a piece of food or other objects get stuck in the upper airway and provoke coughing, gagging, inability to talk, and difficulty breathing. Evidence: TAS. Frequency: Very rare (HP:0040284). (ORPHA:35069)
- Vegetative state (HP:0031358): The absence of wakefulness and consciousness, but in contrast to a coma, there is involuntary opening of the eyes and movements such as teeth grinding, yawning, or thrashing of the extremities. Evidence: TAS. Frequency: Very rare (HP:0040284). (ORPHA:35069)
These phenotypes are associated with the disease Infantile neuroaxonal dystrophy (ORPHA:35069).