Loss of the ability to control the urinary bladder leading to involuntary urination.

A foot where the longitudinal arch of the foot is in contact with the ground or floor when the individual is standing; or, in a patient lying supine, a foot where the arch is in contact with the surface of a flat board pressed against the sole of the foot by the examiner with a pressure similar to that expected from weight bearing; or, the height of the arch is reduced.

Webbing or fusion of the fingers or toes, involving soft parts only or including bone structure. Bony fusions are referred to as "bony" syndactyly if the fusion occurs in a radio-ulnar axis. Fusions of bones of the fingers or toes in a proximo-distal axis are referred to as "symphalangism".

Weakness of the muscles of the arms.

Weakness of the muscles of the legs.

Reduced strength of the distal musculature of the legs.

Fine, rapid twitching of individual muscle fibers with little or no movement of the muscle as a whole as ascertained by electromyography (EMG). If a motor neuron or its axon is destroyed, the muscle fibers it innervates undergo denervation atrophy. This leads to hypersensitivity of individual muscle fibers to acetyl choline so that they may contract spontaneously. Isolated activity of individual muscle fibers is generally so fine it cannot be seen through the intact skin, although it can be recorded as a short-duration spike in the EMG.

Absence of neurologic reflexes such as the knee-jerk reaction.

The term gait disturbance can refer to any disruption of the ability to walk.

Inability to walk in a person who previous had the ability to walk.

The presence of excessive redundant myelin in the peripheral nerve sheath.

An abnormal reduction in sensation in the distal portions of the extremities.

Repeated episodes of segmental demyelination and remyelination lead to the accumulation of supernumerary Schwann cells around axons, which is referred to as onion bulb formation. This finding affects peripheral nerves.

A reduction in the speed at which electrical signals propagate along the axon of a neuron.

Intellectual disability, previously referred to as mental retardation, is characterized by subnormal intellectual functioning that occurs during the developmental period. It is defined by an IQ score below 70.

Partial or complete wasting (loss) of brain tissue that was once present.

The presence of an abnormal lateral curvature of the spine.

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

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

Paralysis of one or more extraocular muscles that are responsible for eye movements.

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.