Phenotypes associated with the disease Spinocerebellar ataxia type 21 (ORPHA:98773):
- 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: Very frequent (HP:0040281). (ORPHA:98773)
- Abnormality of extrapyramidal motor function (HP:0002071): A neurological condition related to lesions of the basal ganglia leading to typical abnormalities including akinesia (inability to initiate changes in activity and perform volitional movements rapidly and easily), muscular rigidity (continuous contraction of muscles with constant resistance to passive movement), chorea (widespread arrhythmic movements of a forcible, rapid, jerky, and restless nature), athetosis (inability to sustain the muscles of the fingers, toes, or other group of muscles in a fixed position), and akathisia (inability to remain motionless). Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:98773)
- Progressive cerebellar ataxia (HP:0002073). Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:98773)
- Intermittent microsaccadic pursuits (HP:0007944). Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:98773)
- Nystagmus (HP:0000639): Rhythmic, involuntary oscillations of one or both eyes related to abnormality in fixation, conjugate gaze, or vestibular mechanisms. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98773)
- 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: Frequent (HP:0040282). (ORPHA:98773)
- Intellectual disability (HP:0001249): The term intellectual disability or intellectual developmental disorder is used to describe significantly sub-average intellectual and adaptive functioning based on clinical assessment and as measured by individually administered, appropriately normed, standardized and validated tests of intellectual functioning and adaptive behavior, with onset during the developmental period from infancy through adolescence. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98773)
- 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: Frequent (HP:0040282). (ORPHA:98773)
- Tremor (HP:0001337): An unintentional, oscillating to-and-fro muscle movement about a joint axis. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98773)
- Rigidity (HP:0002063): Continuous involuntary sustained muscle contraction. When an affected muscle is passively stretched, the degree of resistance remains constant regardless of the rate at which the muscle is stretched. This feature helps to distinguish rigidity from muscle spasticity. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98773)
- Akinesia (HP:0002304): Inability to initiate changes in activity or movement and to perform ordinary volitional movements rapidly and easily. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98773)
- Cerebellar vermis atrophy (HP:0006855): Wasting (atrophy) of the vermis of cerebellum. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98773)
- Dysgraphia (HP:0010526): A writing disability in the absence of motor or sensory deficits of the upper extremities, resulting in an impairment in the ability to write regardless of the ability to read and not due to intellectual impairment. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98773)
- Cognitive impairment (HP:0100543): Abnormal cognition is characterized by deficits in thinking, reasoning, or remembering. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:98773)
- Diplopia (HP:0000651): Diplopia is a condition in which a single object is perceived as two images, it is also known as double vision. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:98773)