Failure to thrive (FTT) refers to a child whose physical growth is substantially below the norm.

Vomiting that ejects the gastric contents with great force.

Schilder's disease is a progressive demyelinating disorder of the central nervous system.

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.

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.

Mild or moderate loss of motor function accompanied by spasticity in the lower extremities. This condition is a manifestation of CENTRAL NERVOUS SYSTEM DISEASES that cause injury to the motor cortex or descending motor pathways.

Abnormality observed by electroencephalogram (EEG), which is used to record of the brain's spontaneous electrical activity from multiple electrodes placed on the scalp.

PLP1 disorders of central nervous system myelin formation include a range of phenotypes from Pelizaeus-Merzbacher disease (PMD) to spastic paraplegia 2 (SPG2). PMD typically manifests in infancy or early childhood with nystagmus, hypotonia, and cognitive impairment; the findings progress to severe spasticity and ataxia. Life span is shortened. SPG2 manifests as spastic paraparesis with or without CNS involvement and usually normal life span. Intrafamilial variation of phenotypes can be observed, but the signs are usually fairly consistent within families. Heterozygous females may manifest mild-to-moderate signs of the disease.

Functional neurological abnormalities related to dysfunction of the pyramidal tract.

Unlocalized atrophy of the brain with decreased total brain matter volume and increased ventricular size.

The presence of atrophy (wasting) of the corpus callosum.

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.

Complete lack of development of speech and language abilities.

A type of spasticity that affects one or more limbs (arms or legs).

A limitation in the passive range of motion of the elbow resulting from loss of elasticity in the periarticular tissues owing to structural changes of non-bony tissues, such as muscles, tendons, ligaments, joint capsules or skin. A contracture prevents movement of the associated body part.

An abnormal curvature of the spine in both a coronal (lateral) and sagittal (back-to-front) plane.

Muscular hypotonia (abnormally low muscle tone) affecting the musculature of the trunk.

Muscular atrophy affecting the lower limb.

Head circumference below 2 standard deviations below the mean for age and gender.

Absence of fine and sharp appearance of brows, nose, lips, mouth, and chin, usually because of rounded and heavy features or thickened skin with or without thickening of subcutaneous and bony tissues.

The birth of a baby of less than 37 weeks of gestational age.

A form of strabismus with one or both eyes deviated outward.

Rhythmic, involuntary oscillations of one or both eyes related to abnormality in fixation, conjugate gaze, or vestibular mechanisms.

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.

Reduced velocity and acceleration in the pupillary light response.