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).

Abnormally low body weight.

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.

Deliberate harm to one's body resulting in tissue damage, without a conscious intent to die.

Use of the same abnormal action in response to certain triggers or at random. They may be used as a way to regulate one's internal state but must otherwise have no apparent functional purpose.

A shaky or wobbly manner of walking.

Reduced attention span characterized by distractibility and impulsivity.

Truncal ataxia is a sign of ataxia characterized by instability of the trunk. It usually occurs during sitting.

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.

An abnormal gait pattern in which persons stand and walk with their feet spaced widely apart. This is often a component of cerebellar ataxia.

A decrease in the level of N-acetyl aspartate in the brain identified by magnetic resonance spectroscopy (MRS).

A failure to achieve the ability to sit at an appropriate developmental stage. Most children sit with support at 6 months of age and sit steadily without support at 9 months of age.

Protrusion of the contents of the abdominal cavity through the inguinal canal.

Head circumference which falls below 2 standard deviations below the mean for age and gender because of insufficient head growth after birth.

Generalized muscular hypotonia (abnormally low muscle tone).

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