- Hearing impairment (HP:0000365): A decreased magnitude of the sensory perception of sound. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:1186)
- Ophthalmoplegia (HP:0000602): Paralysis of one or more extraocular muscles that are responsible for eye movements. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:1186)
- 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: Very frequent (HP:0040281). (ORPHA:1186)
- 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: Very frequent (HP:0040281). (ORPHA:1186)
- Diminished deep tendon reflex (HP:0001315): A reduction (hyporeflexia) or complete absence (areflexia) of the involuntary muscle contraction normally elicited by a reflex stimulus, such as tapping a deep tendon. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:1186)
- Abnormality of the autonomic nervous system (HP:0002270): An abnormality of the autonomic nervous system. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:1186)
- Abnormality of movement (HP:0100022): An abnormality of movement with a neurological basis characterized by changes in coordination and speed of voluntary movements. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:1186)
These phenotypes are associated with the disease Infantile-onset spinocerebellar ataxia (ORPHA:1186).