The presence of abnormally small extremities.

For children from birth to 4 years of age the palm width is more than 2 SD above the mean; for children from 4 to 16 years of age the palm width is above the 95th centile; or, the width of the palm appears disproportionately wide for the length.

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.

A partial dislocation of the hip joint, whereby the head of the femur is partially displaced from the socket.

Short (hypoplastic) phalanx of finger, affecting one or more phalanges.

Diminished length of one or more metacarpal bones in relation to the others of the same hand or to the contralateral metacarpal.

Abnormally broad metacarpal bones.

Short palm.

Abnormally short finger associated with developmental hypoplasia.

Disproportionately long fibulae.

Increased side-to-side width of one or more phalanges of the fingers or toes.

The metatarsals are deviated medially (tibially), that is, the bones in the front half of the foot bend or turn in toward the body.

A type of disproportionate short stature characterized by a short limbs but an average-sized trunk.

External mechanical compression of the spinal cord.

Dilated, glial-lined cavity in spinal cord. This cavity does not communicate with the central canal, and usually is between the dorsal columns unilaterally or bilaterally along the side of the cord.

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.

The presence of calcium deposition in the falx cerebri.

A type of Developmental delay characterized by a delay in acquiring motor skills.

Developmental hypoplasia of the mandible.

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.

The presence of an abnormal lateral curvature of the spine.

A deformity of the chest caused by overgrowth of the ribs and characterized by protrusion of the sternum.

Bilateral bulging of the lateral frontal bone prominences with relative sparing of the midline.

Calcification (abnormal deposits of calcium) in the tracheal tissues.

An elbow contracture that limits the ability of the elbow joint to be extended (straightened), meaning that the elbow is fixed in an flexed (bent) position.

Abnormally increased movement at the junction between the first cervical (atlas) and the second cervical (axis) vertebrae as a result of either a bony or ligamentous anomaly.

Reduced width of the chest from side to side, associated with a reduced distance from the sternal notch to the tip of the shoulder.

Reduced rib length.

An osteochondrodysplasia that results in abnormalities of bone growth in the vertebral column, epiphysis, and metaphysis.

Wide, concave posterior rib end.

A flattened vertebral body shape with reduced distance between the vertebral endplates.

Wide, concave anterior rib end.

The odontoid process, or dens, is a bony projection from the axis (C2) upward into the ring of the atlas (C1) at the top of the spine. During embryogenesis, the body of the odontoid derives from the centrum of the atlas and separates from the atlas, fusing with the superior portion of the axis. If the odontoid is hypoplastic or absent, the attachments for the apical and alar ligaments are missing, allowing for excessive rotation of the atlas, craniocervical instability, and possibly cord compression (summary by Stevens et al., 2009).

A partial dislocation of the atlantoaxial joints.

The presence of a splayed (i.e.,flared) metaphyseal segment of one or more long bones.

One or more abnormally short long bone.

Underdevelopment of the malar prominence of the jugal bone (zygomatic bone in mammals), appreciated in profile, frontal view, and/or by palpation.

The presence of abnormal punctate (speckled, dot-like) calcifications in one or more epiphyses.

The rib cage has the shape of a wide mouthed bell. That is, the superior portion of the rib cage is constricted, followed by a convex region, and the inferior portion of the rib cage expands again to have a large diameter.

Widening of the ilium ala, that is of the wing of the ilium, combined with external rotation, leading to a flared appearance of the iliac wing.

Enlargement of the anterior fontanelle with respect to age-dependent norms.

A defect of the chest wall characterized by a depression of the sternum, giving the chest ("pectus") a caved-in ("excavatum") appearance.

Increased cross-section (diameter) of the long bones. Note that widening may primarily affect specific regions of long bones (e.g., diaphysis or metaphysis), but this should be coded separately.

The presence of calcium deposition in cartilage.

A bending or abnormal curvature affecting a long bone of the leg.

An increased susceptibility to pneumonia as manifested by a history of recurrent episodes of pneumonia.

A functional defect characterized by reduced total lung capacity (TLC) not associated with abnormalities of expiratory airflow or airway resistance. Spirometrically, a restrictive defect is defined as FEV1 (forced expiratory volume in 1 second) and FVC (forced vital capacity) less than 80 per cent. Restrictive lung disease may be caused by alterations in lung parenchyma or because of a disease of the pleura, chest wall, or neuromuscular apparatus.

Height of the palate more than 2 SD above the mean (objective) or palatal height at the level of the first permanent molar more than twice the height of the teeth (subjective).

Nasal ridge curving posteriorly to an imaginary line that connects the nasal root and tip.

Increased aperture of the nostril.

Diminished length of the neck.

Posterior positioning of the nasal root in relation to the overall facial profile for age.

Lack of prominence of the nose resulting from a posteriorly-placed nasal ridge.

Posterior positions and/or vertical shortening of the infraorbital and perialar regions, or increased concavity of the face and/or reduced nasolabial angle.

Distance from nasion to subnasale more than two standard deviations below the mean, or alternatively, an apparently decreased length from the nasal root to the nasal tip.

Bizygomatic (upper face) and bigonial (lower face) width greater than 2 standard deviations above the mean (objective); or an apparent increase in the width of the face (subjective).

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.

An eye that is protruding anterior to the plane of the face to a greater extent than is typical.

Although hypertelorism means an excessive distance between any paired organs (e.g., the nipples), the use of the word has come to be confined to ocular hypertelorism. Hypertelorism occurs as an isolated feature and is also a feature of many syndromes, e.g., Opitz G syndrome (see 300000), Greig cephalopolysyndactyly (175700), and Noonan syndrome (163950) (summary by Cohen et al., 1995).