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".

Digits that appear disproportionately short compared to the hand/foot. The word brachydactyly is used here to describe a series distinct patterns of shortened digits (brachydactyly types A-E). This is the sense used here.

With the hand relaxed and the thumb in the plane of the palm, the axis of the thumb forms an angle of at least 90 degrees with the long axis of the hand.

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

Diminished length of a metatarsal bone, with resultant proximal displacement of the associated toe.

An angulation of a digit at an interphalangeal joint in the plane of the palm (finger) or sole (toe).

A bilateral form of sensorineural hearing impairment.

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 osseous union (fusion) between the radius and the ulna.

Synostosis (bony fusion) involving one or more bones of the tarsus (calcaneus, talus, cuboid, navicular, cuneiiform bones).

Synostosis (bony fusion) involving one or more bones of the carpus (scaphoid, lunate, triquetrum, trapezium, trapezoid, capitate, hamate, pisiform).

Asymmetric head shape, which is usually a combination of unilateral occipital flattening with ipsilateral frontal prominence, leading to rhomboid cranial shape.

Increased space between two adjacent teeth in the same dental arch.

Decreased size of the teeth, which can be defined as a mesiodistal tooth diameter (width) more than 2 SD below mean. Alternatively, an apparently decreased maximum width of tooth.

Talon cusp is an accessory cusp located near the cingulum (the portion of the lingual or palatal aspect of the tooth that forms a convex protuberance at the cervical third of the anatomic crown).

Accentuated, prominent philtral ridges giving rise to an exaggerated groove in the midline between the nasal base and upper vermillion border.

Increased height of the central portion of the eyebrow, forming a crescent, semicircular, or inverted U shape.

Cleft palate is a developmental defect of the palate resulting from a failure of fusion of the palatine processes and manifesting as a separation of the roof of the mouth (soft and hard palate).

Meeting of the medial eyebrows in the midline.

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).

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.

An abnormal bluish coloration of the sclera.