Phenotypes associated with the disease leukodystrophy, hypomyelinating, 18 (OMIM:618404):
- 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:618404)
- 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: IEA. (OMIM:618404)
- 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: IEA. (OMIM:618404)
- 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: 12/19. (PMID:30620337)
- 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: IEA. (OMIM:618404)
- Flexion contracture (HP:0001371): A flexion contracture is a bent (flexed) joint that cannot be straightened actively or passively. It is thus a chronic loss of joint motion due to structural changes in muscle, tendons, ligaments, or skin that prevents normal movement of joints. Evidence: IEA. (OMIM:618404)
- Nystagmus (HP:0000639): Rhythmic, involuntary oscillations of one or both eyes related to abnormality in fixation, conjugate gaze, or vestibular mechanisms. Evidence: PCS. Frequency: 12/19. Onset: Infantile onset (HP:0003593). (PMID:30620337)
- Failure to thrive (HP:0001508): Failure to thrive (FTT) refers to a child whose physical growth is substantially below the norm. Evidence: PCS. Frequency: 12/18. (PMID:30620337)
- Abnormal motor nerve conduction velocity (HP:0040131). Evidence: PCS. Frequency: 5/12. (PMID:30620337)
- Variable expressivity (HP:0003828): A variable severity of phenotypic features. Evidence: IEA. (OMIM:618404)
- Atrophy/Degeneration affecting the brainstem (HP:0007366). Evidence: IEA. (OMIM:618404)
- Abnormal periventricular white matter morphology (HP:0002518): A structural abnormality of the myelinated axons (white matter) located near the cerebral ventricles. Evidence: IEA. (OMIM:618404)
- Demyelinating peripheral neuropathy (HP:0007108): Demyelinating neuropathy is characterized by slow nerve conduction velocities with reduced amplitudes of sensory/motor nerve conduction and prolonged distal latencies. Evidence: IEA. Frequency: Very rare (HP:0040284). (OMIM:618404)
- Spastic tetraplegia (HP:0002510): Spastic paralysis affecting all four limbs. Evidence: IEA. (OMIM:618404)
- Absent speech (HP:0001344): Complete lack of development of speech and language abilities. Evidence: PCS. Frequency: 13/19. (PMID:30620337)
- 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: 19/19. (PMID:30620337)
- Scoliosis (HP:0002650): The presence of an abnormal lateral curvature of the spine. Evidence: IEA. (OMIM:618404)
- 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: IEA. (OMIM:618404)
- Feeding difficulties (HP:0011968): Impaired ability to eat related to problems gathering food and getting ready to suck, chew, or swallow it. Evidence: PCS. (PMID:30620337)
- 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: IEA. (OMIM:618404)
- Global developmental delay (HP:0001263): A delay in the achievement of motor or mental milestones in the domains of development of a child, including motor skills, speech and language, cognitive skills, and social and emotional skills. This term should only be used to describe children younger than five years of age. Evidence: PCS. Frequency: 19/19. (PMID:30620337)
- Secondary microcephaly (HP:0005484): Head circumference which falls below 2 standard deviations below the mean for age and gender because of insufficient head growth after birth. Evidence: PCS. Frequency: 3/17. (PMID:30620337)
- Progressive spasticity (HP:0002191): Spasticity that increases in degree with time. Evidence: IEA. (OMIM:618404)
- Severe global developmental delay (HP:0011344): A severe delay in the achievement of motor or mental milestones in the domains of development of a child. Evidence: IEA. (OMIM:618404)
- Gastrostomy tube feeding in infancy (HP:0011471): Feeding problem necessitating gastrostomy tube feeding. Evidence: PCS. Frequency: 8/19. (PMID:30620337)
- 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:30620337)
- 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: 18/19. Onset: Infantile onset (HP:0003593). (PMID:30620337)
- Decreased nerve conduction velocity (HP:0000762): A reduction in the speed at which electrical signals propagate along the axon of a neuron. Evidence: IEA. Frequency: Very rare (HP:0040284). (OMIM:618404)