- Poor speech (HP:0002465). Evidence: IEA. (OMIM:612438)
- 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: IEA. (OMIM:612438)
- 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: 10/11. (PMID:23582646)
- Short stature (HP:0004322): A height below that which is expected according to age and gender norms. Although there is no universally accepted definition of short stature, many refer to "short stature" as height more than 2 standard deviations below the mean for age and gender (or below the 3rd percentile for age and gender dependent norms). Evidence: IEA. (OMIM:612438)
- 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. (PMID:23582646)
- 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: 1/11. (PMID:23582646)
- 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: PCS. Frequency: 9/11. (PMID:23582646)
- Hypotonia (HP:0001252): Hypotonia is an abnormally low muscle tone (the amount of tension or resistance to movement in a muscle). Even when relaxed, muscles have a continuous and passive partial contraction which provides some resistance to passive stretching. Hypotonia thus manifests as diminished resistance to passive stretching. Hypotonia is not the same as muscle weakness, although the two conditions can co-exist. Evidence: PCS. Frequency: 2/11. (PMID:23582646)
- 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: PCS. Frequency: 8/11. (PMID:23582646)
- Cerebral hypomyelination (HP:0006808): Reduced amount of myelin in the nervous system resulting from defective myelinogenesis in the white matter of the central nervous system. Evidence: IEA. (OMIM:612438)
- Infantile onset (HP:0003593): Onset of signs or symptoms of disease between 28 days to one year of life. Evidence: PCS. Frequency: 2/11. (PMID:23582646)
- Motor delay (HP:0001270): A type of Developmental delay characterized by a delay in acquiring motor skills. Evidence: PCS. Frequency: 7/11. (PMID:23582646)
- Nystagmus (HP:0000639): Rhythmic, involuntary oscillations of one or both eyes related to abnormality in fixation, conjugate gaze, or vestibular mechanisms. Evidence: PCS. Frequency: 2/11. (PMID:23582646)
- Childhood onset (HP:0011463): Onset of disease at the age of between 1 and 5 years. Evidence: PCS. Frequency: 9/11. (PMID:23582646)
- Specific learning disability (HP:0001328): Impairment of certain skills such as reading or writing, coordination, self-control, or attention that interfere with the ability to learn. The impairment is not related to a global deficiency of intelligence. Evidence: IEA. (OMIM:612438)
- Oculomotor apraxia (HP:0000657): Ocular motor apraxia is a deficiency in voluntary, horizontal, lateral, fast eye movements (saccades) with retention of slow pursuit movements. The inability to follow objects visually is often compensated by head movements. There may be decreased smooth pursuit, and cancelation of the vestibulo-ocular reflex. Evidence: PCS. Frequency: 2/11. (PMID:23582646)
- Sporadic (HP:0003745): Cases of the disease in question occur without a previous family history, i.e., as isolated cases without being transmitted from a parent and without other siblings being affected. Evidence: IEA. (OMIM:612438)
- Leukodystrophy (HP:0002415): 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. Frequency: 11/11. (PMID:23582646)
- 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: PCS. (PMID:23582646)
- Axial hypotonia (HP:0008936): Muscular hypotonia (abnormally low muscle tone) affecting the musculature of the trunk. Evidence: IEA. (OMIM:612438)
- Microcephaly (HP:0000252): Head circumference below 2 standard deviations below the mean for age and gender. Evidence: IEA. (OMIM:612438)
- Hypometric saccades (HP:0000571): Saccadic undershoot, i.e., a saccadic eye movement that has less than the magnitude that would be required to gain fixation of the object. Evidence: PCS. Frequency: 2/11. (PMID:23582646)
- 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: 6/11. (PMID:23582646)
- Choreoathetosis (HP:0001266): Involuntary movements characterized by both athetosis (inability to sustain muscles in a fixed position) and chorea (widespread jerky arrhythmic movements). Evidence: PCS. Frequency: 5/11. (PMID:23582646)
- Developmental regression (HP:0002376): Loss of developmental skills, as manifested by loss of developmental milestones. Evidence: PCS. Frequency: 11/11. (PMID:23582646)
- 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: 11/11. (PMID:23582646)
- 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: IEA. (OMIM:612438)
- Visual impairment (HP:0000505): 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: PCS. Frequency: 1/11. (PMID:23582646)
- Spasticity (HP:0001257): A motor disorder characterized by a velocity-dependent increase in tonic stretch reflexes with increased muscle tone, exaggerated (hyperexcitable) tendon reflexes. Evidence: PCS. Frequency: 11/11. (PMID:23582646)
- Autosomal dominant inheritance (HP:0000006): 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 heterozygotes. In the context of medical genetics, an autosomal dominant disorder is caused when a single copy of the mutant allele is present. Males and females are affected equally, and can both transmit the disorder with a risk of 50% for each child of inheriting the mutant allele. Evidence: PCS. (PMID:23582646)
- Tremor (HP:0001337): An unintentional, oscillating to-and-fro muscle movement about a joint axis. Evidence: PCS. Frequency: 8/11. (PMID:23582646)
These phenotypes are associated with the disease leukodystrophy, hypomyelinating, 6 (OMIM:612438).