- Progressive (HP:0003676): Applies to a disease manifestation that increases in scope or severity over the course of time, i.e., that worsens with age. Evidence: PCS. (PMID:19068277)
- 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. (OMIM:612319)
- Dysmetria (HP:0001310): A type of ataxia characterized by the inability to carry out movements with the correct range and motion across the plane of more than one joint related to incorrect estimation of the distances required for targeted movements. Evidence: PCS. (PMID:19068277)
- 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: PCS. Frequency: 7/9. (PMID:19068277)
- 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. (OMIM:612319)
- 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: PCS. Frequency: 2/9. (PMID:19068277)
- Urinary incontinence (HP:0000020): Loss of the ability to control the urinary bladder leading to involuntary urination. Evidence: TAS. Frequency: Occasional (HP:0040283). (OMIM:612319)
- 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. (OMIM:612319)
- 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: PCS. Frequency: 9/9. (PMID:19068277)
- Neurodegeneration (HP:0002180): Progressive loss of neural cells and tissue. Evidence: IEA. (OMIM:612319)
- Thin corpus callosum (HP:0033725): An abnormally thin corpus callous, due to atrophy, hypoplasia or agenesis. This term is intended to be used in situations where it is not known if thinning of the corpus callosum (for instance, as visualized by magnetic resonance tomography) is due to abnormal development (e.g. a leukodystrophy) or atrophy following normal development (e.g. neurodegeneration). Evidence: PCS. Frequency: 3/9. (PMID:19068277)
- Nystagmus (HP:0000639): Rhythmic, involuntary oscillations of one or both eyes related to abnormality in fixation, conjugate gaze, or vestibular mechanisms. Evidence: TAS. (OMIM:612319)
- Childhood onset (HP:0011463): Onset of disease at the age of between 1 and 5 years. Evidence: PCS. Frequency: 7/9. (PMID:19068277)
- Abnormal periventricular white matter morphology (HP:0002518): A structural abnormality of the myelinated axons (white matter) located near the cerebral ventricles. Evidence: TAS. (OMIM:612319)
- Atrophy/Degeneration affecting the brainstem (HP:0007366). Evidence: TAS. (OMIM:612319)
- Mental deterioration (HP:0001268): Loss of previously present mental abilities, generally in adults. Evidence: PCS. (PMID:19068277)
- 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. (OMIM:612319)
- Hyperreflexia (HP:0001347): Hyperreflexia is the presence of hyperactive stretch reflexes of the muscles. Evidence: TAS. (OMIM:612319)
- Dysmyelinating leukodystrophy (HP:0006978). Evidence: TAS. (OMIM:612319)
- Juvenile onset (HP:0003621): Onset of signs or symptoms of disease between the age of 5 and 15 years. Evidence: PCS. Frequency: 2/9. (PMID:19068277)
- Babinski sign (HP:0003487): Upturning of the big toe (and sometimes fanning of the other toes) in response to stimulation of the sole of the foot. If the Babinski sign is present it can indicate damage to the corticospinal tract. Evidence: PCS. Onset: Juvenile onset (HP:0003621). (PMID:19068277)
- Gait disturbance (HP:0001288): The term gait disturbance can refer to any disruption of the ability to walk. Evidence: PCS. Frequency: 9/9. (PMID:19068277)
- Hypoplasia of the corpus callosum (HP:0002079): Underdevelopment of the corpus callosum. Evidence: TAS. (OMIM:612319)
- Urinary urgency (HP:0000012): Urge incontinence is the strong, sudden need to urinate. Evidence: TAS. (OMIM:612319)
- 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. (OMIM:612319)
- Spastic tetraparesis (HP:0001285): Spastic weakness affecting all four limbs. Evidence: TAS. (OMIM:612319)
- Dysdiadochokinesis (HP:0002075): A type of ataxia characterized by the impairment of the ability to perform rapidly alternating movements, such as pronating and supinating his or her hand on the dorsum of the other hand as rapidly as possible. Evidence: PCS. (PMID:19068277)
- Ankle clonus (HP:0011448): Clonus is an involuntary tendon reflex that causes repeated flexion and extension of the foot. Ankle clonus is tested by rapidly flexing the foot upward. Evidence: TAS. Frequency: Occasional (HP:0040283). (OMIM:612319)
- Autosomal recessive inheritance (HP:0000007): A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in individuals with two pathogenic alleles, either homozygotes (two copies of the same mutant allele) or compound heterozygotes (whereby each copy of a gene has a distinct mutant allele). Evidence: PCS. (PMID:19068277)
- 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. (OMIM:612319)
- Spastic paraplegia (HP:0001258): Complete loss of the ability to move the lower limbs accompanied by spasticity of the lower limbs. Evidence: PCS. (PMID:19068277)
- External ophthalmoplegia (HP:0000544): Paralysis of the external ocular muscles. Evidence: TAS. Frequency: Occasional (HP:0040283). (OMIM:612319)
These phenotypes are associated with the disease hereditary spastic paraplegia 35 (OMIM:612319).