A myocardial disorder in which the heart muscle is structurally and functionally abnormal, in the absence of coronary artery disease, hypertension, valvular disease and congenital heart disease sufficient to cause the observed myocardial abnormality.

An abnormal restriction of fetal growth with fetal weight below the tenth percentile for gestational age.

Impaired ability to eat related to problems gathering food and getting ready to suck, chew, or swallow it.

Aggressive behavior can denote verbal aggression, physical aggression against objects, physical aggression against people, and may also include aggression towards oneself.

A slow, continuous, involuntary writhing movement that prevents maintenance of a stable posture. Athetosis involves continuous smooth movements that appear random and are not composed of recognizable sub-movements or movement fragments. In contrast to chorea, in athetosis, the same regions of the body are repeatedly involved. Athetosis may worsen with attempts at movement of posture, but athetosis can also occur at rest.

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).

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.

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.

A seizure is an intermittent abnormality of nervous system physiology characterised by a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain.

A term referring to disorders characterized by the disruption of normal speech. It includes stuttering, lisps, dysarthria and voice disorders.

An unintentional, oscillating to-and-fro muscle movement about a joint axis.

Hyperreflexia is the presence of hyperactive stretch reflexes of the muscles.

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.

Atrophy (wasting, decrease in size of cells or tissue) affecting the cerebrum.

This term describes abnormality of the white matter of the cerebrum resulting from damage to the myelin sheaths of nerve cells.

Spastic paralysis affecting all four limbs.

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.

Diffuse unlocalised atrophy affecting the cerebrum.

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.

Complete lack of development of speech and language abilities.

An increase in size of the ventricular system of the brain.

Seizures that start from several different areas of the brain (i.e., with multiple ictal onset locations).

Subnormal intellectual functioning which originates during the developmental period. Intellectual disability, previously referred to as mental retardation, has been defined as an IQ score below 70.

Delayed myelination in the central nervous system.

Temper tantrums whose severity is more severe than usual. For instance, a temper tantrum might be considered to be severe if a child loses control so completely that the child cannot control the tantrum on its own, continuing until it becomes exhausted or a parent intervenes.

A reduction in the number of circulating thrombocytes.

A condition in which there is increased muscle tone so that arms or legs, for example, are stiff and difficult to move.

Reduced strength of muscles.

The presence of skeletal muscular atrophy (which is also known as amyotrophy).

Generalized (diffuse, unlocalized) amyotrophy (muscle atrophy) affecting multiple muscles.

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

An abnormal buildup of lactic acid in the body, leading to acidification of the blood and other bodily fluids.

A decreased concentration of glucose in the blood.

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).

Distance between nasal base and midline upper lip vermilion border more than 2 SD above the mean. Alternatively, an apparently increased distance between nasal base and midline upper lip vermilion border.

Reduced visual acuity that is uncorrectable by lenses in the absence of detectable anatomic defects in the eye or visual pathways.

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.

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.

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.

An inherited retinal disease subtype in which the rod photoreceptors appear to be more severely affected than the cone photoreceptors. Typical presentation is with nyctalopia (due to rod dysfunction) followed by loss of mid-peripheral field of vision, which gradually extends and leaves many patients with a small central island of vision due to the preservation of macular cones.