- Spastic diplegia (HP:0001264, a Human Phenotype Ontology term): Spasticity (neuromuscular hypertonia) primarily in the muscles of the legs, hips, and pelvis. Evidence: PCS. (PMID:24334290)
- Strabismus (HP:0000486, a Human Phenotype Ontology term): 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. (PMID:21471552)
- Gait disturbance (HP:0001288, a Human Phenotype Ontology term): The term gait disturbance can refer to any disruption of the ability to walk. Evidence: PCS. (PMID:21471552)
- Hypoplasia of the corpus callosum (HP:0002079, a Human Phenotype Ontology term): Underdevelopment of the corpus callosum. Evidence: PCS. (PMID:21471552)
- Babinski sign (HP:0003487, a Human Phenotype Ontology term): 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. (PMID:21471552)
- Spastic ataxia (HP:0002497, a Human Phenotype Ontology term). Evidence: PCS. (PMID:24334290)
- Seizure (HP:0001250, a Human Phenotype Ontology term): 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. (PMID:24334290)
- Hyperglycinemia (HP:0002154, a Human Phenotype Ontology term): An elevated concentration of glycine in the blood. Evidence: PCS. Frequency: 8/8. (PMID:21471552)
- Dysarthria (HP:0001260, a Human Phenotype Ontology term): 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. (PMID:24334290)
- Increased circulating lactate concentration (HP:0002151, a Human Phenotype Ontology term): Abnormally increased level of blood lactate (2-hydroxypropanoic acid). Lactate is produced from pyruvate by lactate dehydrogenase during normal metabolism. The terms lactate and lactic acid are often used interchangeably but lactate (the component measured in blood) is strictly a weak base whereas lactic acid is the corresponding acid. Lactic acidosis is often used clinically to describe elevated lactate but should be reserved for cases where there is a corresponding acidosis (pH below 7.35). Evidence: PCS. Frequency: 4/7. (PMID:24334290)
- Increased CSF lactate (HP:0002490, a Human Phenotype Ontology term): Increased concentration of lactate in the cerebrospinal fluid. Evidence: PCS. Frequency: 2/7. (PMID:24334290)
- Reduced tissue glycine cleavage enzyme activity (HP:6000829, a Human Phenotype Ontology term): Concentration or activity of the glycine cleavage enzyme below the lower limit of normal. This enzyme can be measured in multiple tissues including leukocytes and cultured fibroblasts. Evidence: PCS. Frequency: 2/2. (PMID:24334290)
- Increased CSF glycine concentration (HP:0500230, a Human Phenotype Ontology term): Abnormally increased levels of glycine in cerebrospinal fluid. Evidence: PCS. Frequency: 4/8. (PMID:24334290)
- Nystagmus (HP:0000639, a Human Phenotype Ontology term): Rhythmic, involuntary oscillations of one or both eyes related to abnormality in fixation, conjugate gaze, or vestibular mechanisms. Evidence: PCS. (PMID:21471552)
- Decreased activity of the pyruvate dehydrogenase complex (HP:0002928, a Human Phenotype Ontology term). Evidence: PCS. (PMID:24334290)
- Autosomal recessive inheritance (HP:0000007, a Human Phenotype Ontology term): 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:24334290)
- Abnormal pyramidal sign (HP:0007256, a Human Phenotype Ontology term): Functional neurological abnormalities related to dysfunction of the pyramidal tract. Evidence: PCS. (PMID:24334290)
- Optic atrophy (HP:0000648, a Human Phenotype Ontology term): 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. (PMID:21471552)
- Visual impairment (HP:0000505, a Human Phenotype Ontology term): Visual impairment (or vision impairment) is vision loss (of a person) to such a degree as to qualify as an additional support need through a significant limitation of visual capability resulting from either disease, trauma, or congenital or degenerative conditions that cannot be corrected by conventional means, such as refractive correction, medication, or surgery. Evidence: TAS. (OMIM:616859)
- Leukodystrophy (HP:0002415, a Human Phenotype Ontology term): Leukodystrophy refers to deterioration of white matter of the brain resulting from degeneration of myelin sheaths in the CNS. Their basic defect is directly related to the synthesis and maintenance of myelin membranes. Symmetric white matter involvement at MRI is a typical finding in patients with leukodystrophies. Evidence: PCS. (PMID:21471552)
- Spasticity (HP:0001257, a Human Phenotype Ontology term): A motor disorder characterized by a velocity-dependent increase in tonic stretch reflexes with increased muscle tone, exaggerated (hyperexcitable) tendon reflexes. Evidence: PCS. (PMID:21471552)
- Hyperreflexia (HP:0001347, a Human Phenotype Ontology term): Hyperreflexia is the presence of hyperactive stretch reflexes of the muscles. Evidence: PCS. (PMID:21471552)
These phenotypes are associated with the disease spasticity-ataxia-gait anomalies syndrome (OMIM:616859, an entry in Online Mendelian Inheritance in Man).