- 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: Very frequent (HP:0040281). (ORPHA:101110)
- 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: Frequent (HP:0040282). (ORPHA:101110)
- Dysphonia (HP:0001618): Difficulty in speaking due to a physical disorder of the mouth, tongue, throat, or vocal cords. Associated with a known physical or neurological cause. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:101110)
- Bradykinesia (HP:0002067): Bradykinesia literally means slow movement, and is used clinically to denote a slowness in the execution of movement (in contrast to hypokinesia, which is used to refer to slowness in the initiation of movement). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:101110)
- Cerebral calcification (HP:0002514): The presence of calcium deposition within the cerebrum. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:101110)
- Hypermetric saccades (HP:0007338): A saccade that overshoots the target with the dynamic saccade. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:101110)
- Laryngeal dystonia (HP:0012049): A form of focal dystonia that affects the vocal cords, associated with involuntary contractions of the vocal cords causing interruptions of speech and affecting the voice quality and often leading to patterned, repeated breaks in speech. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:101110)
- Tremor by anatomical site (HP:0030188): Tremor classified by the affected body part. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:101110)
- Gaze-evoked nystagmus (HP:0000640): Nystagmus made apparent by looking to the right or to the left. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:101110)
- 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:101110)
- Hyperreflexia (HP:0001347): Hyperreflexia is the presence of hyperactive stretch reflexes of the muscles. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:101110)
- Gait ataxia (HP:0002066): A type of ataxia characterized by the impairment of the ability to coordinate the movements required for normal walking. Gait ataxia is characteirzed by a wide-based staggering gait with a tendency to fall. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:101110)
- Vertigo (HP:0002321): An abnormal sensation of spinning while the body is actually stationary. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:101110)
- Abnormal pyramidal sign (HP:0007256): Functional neurological abnormalities related to dysfunction of the pyramidal tract. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:101110)
- Upper limb postural tremor (HP:0007351): A type of tremors that is triggered by holding an arm in a fixed position. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:101110)
- 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: Occasional (HP:0040283). (ORPHA:101110)
- Isometric tremor (HP:0030185): An isometric tremor occurs with muscle contraction against a rigid stationary object (e.g., when making a fist). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:101110)
- Kinetic tremor (HP:0030186): Tremor that occurs during any voluntary movement. It may include visually or non-visually guided movements. Tremor during target directed movement is called intention tremor. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:101110)
- Intention tremor (HP:0002080): A type of kinetic tremor that occurs during target directed movement is called intention tremor. That is, an oscillatory cerebellar ataxia that tends to be absent when the limbs are inactive and during the first part of voluntary movement but worsening as the movement continues and greater precision is required (e.g., in touching a target such as the patient's nose or a physician's finger). Evidence: TAS. Frequency: Very rare (HP:0040284). (ORPHA:101110)
These phenotypes are associated with the disease Spinocerebellar ataxia type 20 (ORPHA:101110).