Clubfoot is a congenital limb deformity defined as fixation of the foot in cavus, adductus, varus, and equinus (i.e., inclined inwards, axially rotated outwards, and pointing downwards) with concomitant soft tissue abnormalities (Cardy et al., 2007). Clubfoot may occur in isolation or as part of a syndrome (e.g., diastrophic dysplasia, 222600). Clubfoot has been reported with deficiency of long bones and mirror-image polydactyly (Gurnett et al., 2008; Klopocki et al., 2012).

A type of knee joint contracture in which the knee is in a fixed bent (flexed) configuration such that it cannot be straightened actively or passively.

An increase in height of the medial longitudinal arch of the foot that does not flatten on weight bearing (i.e., a distinctly hollow form of the sole of the foot when it is bearing weight).

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

A failure to achieve the ability to walk at an appropriate developmental stage. Most children learn to walk in a series of stages, and learn to walk short distances independently between 12 and 15 months.

Incapability to ambulate.

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

An abnormality characterized by disruption of the normal functioning of peripheral axons.

A loss of myelinated nerve fibers in the peripheral nervous system (in general, this finding can be observed on nerve biopsy).

A type of decreased nerve conduction velocity that affects the motor neuron.

Hypotonia is an abnormally low muscle tone (the amount of tension or resistance to movement in a muscle). Even when relaxed, muscles have a continuous and passive partial contraction which provides some resistance to passive stretching. Hypotonia thus manifests as diminished resistance to passive stretching. Hypotonia is not the same as muscle weakness, although the two conditions can co-exist.

Reduced strength of muscles.

Atrophy of the intrinsic muscle groups of the hand, comprising the thenar and hypothenar muscles; the interossei muscles; and the lumbrical muscles.

Impairment of gas exchange within the lungs secondary to a disease process, neoplasm, or trauma, possibly resulting in hypoxia, hypercarbia, or both, but not requiring intubation or mechanical ventilation. Patients are normally managed with pharmaceutical therapy, supplemental oxygen, or both.

Congenital tracheomalacia is a rare condition where the trachea is soft and flexible causing the tracheal wall to collapse when exhaling, coughing or crying, that usually presents in infancy, and that is characterized by stridor and noisy breathing or upper respiratory infections. Tracheomalacia improves by the age of 18-24 months.

A loss of the ability to move the vocal folds.