- Clonus (HP:0002169): A series of rhythmic and involuntary muscle contractions (at a frequency of about 5 to 7 Hz) that occur in response to an abruptly applied and sustained stretch. Evidence: PCS. Frequency: 2/5. (PMID:31855247)
- Dysphagia (HP:0002015): Difficulty in swallowing. Evidence: PCS. Frequency: 4/5. (PMID:31855247)
- 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: PCS. Frequency: 2/5. (PMID:31855247)
- 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: PCS. Frequency: 3/5. (PMID:31855247)
- EEG abnormality (HP:0002353): Abnormality observed by electroencephalogram (EEG), which is used to record of the brain's spontaneous electrical activity from multiple electrodes placed on the scalp. Evidence: PCS. Frequency: 1/4. (PMID:31855247)
- 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: 2/5. (PMID:31855247)
- 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. Frequency: 3/5. (PMID:31855247)
- Febrile seizure (within the age range of 3 months to 6 years) (HP:0002373): A febrile seizure is any type of seizure (most often a generalized tonic-clonic seizure) occurring with fever (at least 38 degrees Celsius) but in the absence of central nervous system infection, severe metabolic disturbance or other alternative precipitant in children between the ages of 3 months and 6 years. Evidence: PCS. Frequency: 1/5. (PMID:31855247)
- 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: PCS. Frequency: 3/5. (PMID:31855247)
- 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: PCS. Frequency: 4/5. (PMID:31855247)
- Urinary incontinence (HP:0000020): Loss of the ability to control the urinary bladder leading to involuntary urination. Evidence: PCS. Frequency: 4/4. (PMID:31855247)
- Progressive cerebellar ataxia (HP:0002073). Evidence: PCS. Frequency: 4/5. (PMID:31855247)
- Substantia nigra hypointensity on susceptibility-weighted imaging (HP:0033048): Hypointence (dark) appearance of the substantia nigra inmagnetic resonance imaging using susceptibility weighted imaging (SWI). Evidence: PCS. Frequency: 2/5. (PMID:31855247)
- Globus pallidus hypointensity on susceptibility-weighted imaging (HP:0033049): Hypointence (dark) appearance of the globus pallidus inmagnetic resonance imaging using susceptibility weighted imaging (SWI). Evidence: PCS. Frequency: 2/5. (PMID:31855247)
- Bowel incontinence (HP:0002607): Involuntary fecal soiling in adults and children who have usually already been toilet trained. Evidence: PCS. Frequency: 2/3. (PMID:31855247)
- Slow saccadic eye movements (HP:0000514): An abnormally slow velocity of the saccadic eye movements. Evidence: PCS. Frequency: 4/5. (PMID:31855247)
- 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:31855247)
- 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: PCS. Frequency: 4/4. (PMID:31855247)
- Mental deterioration (HP:0001268): Loss of previously present mental abilities, generally in adults. Evidence: PCS. Frequency: 4/5. (PMID:31855247)
- Prolonged neonatal jaundice (HP:0006579): Neonatal jaundice refers to a yellowing of the skin and other tissues of a newborn infant as a result of increased concentrations of bilirubin in the blood. Neonatal jaundice affects over half of all newborns to some extent in the first week of life. Prolonged neonatal jaundice is said to be present if the jaundice persists for longer than 14 days in term infants and 21 days in preterm infants. Evidence: PCS. Frequency: 2/5. Onset: Neonatal onset (HP:0003623). (PMID:31855247)
These phenotypes are associated with the disease neurodegeneration, childhood-onset, with ataxia, tremor, optic atrophy, and cognitive decline (OMIM:618868).