The gradual reduction in girth of the finger from proximal to distal.

Clinodactyly refers to a bending or curvature of the fifth finger in the radial direction (i.e., towards the 4th finger).

The middle finger is more than 2 SD above the mean for newborns 27 to 41 weeks EGA or above the 97th centile for children from birth to 16 years of age AND the five digits retain their normal length proportions relative to each other (i.e., it is not the case that the middle finger is the only lengthened digit), or, Fingers that appear disproportionately long compared to the palm of the hand.

Delayed or lack of conduction of atrial depolarizations through the atrioventricular node to the ventricles.

A slower than normal heart rate (in adults, slower than 60 beats per minute).

A deficiency or slowing down of growth pre- and postnatally.

Failure to thrive (FTT) refers to a child whose physical growth is substantially below the norm.

Median longitudinal ear length greater than two standard deviations above the mean and median ear width greater than two standard deviations above the mean (objective); or, apparent increase in length and width of the pinna (subjective).

The presence of an abnormally prominent antihelix.

An abnormally increased muscular tone that causes fixed abnormal postures. There is a slow, intermittent twisting motion that leads to exaggerated turning and posture of the extremities and trunk.

Hyperreflexia is the presence of hyperactive stretch reflexes of the muscles.

Cerebellar hypoplasia is a descriptive term implying a cerebellum with a reduced volume, but a normal shape and is stable over time.

Underdevelopment of the corpus callosum.

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

An abnormality of the cerebral white matter.

Complete lack of development of speech and language abilities.

An abnormality of the cerebral cortex with fewer gyri but with normal cortical thickness. This pattern is usually often associated with congenital microcephaly.

Profound mental retardation is defined as an intelligence quotient (IQ) below 20.

A type of kinetic tremor that occurs during target directed movement is called intention tremor. That is, an oscillatory cerebellar ataxia that tends to be absent when the limbs are inactive and during the first part of voluntary movement but worsening as the movement continues and greater precision is required (e.g., in touching a target such as the patient's nose or a physician's finger).

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.

Progressive microcephaly is diagnosed when the head circumference falls progressively behind age- and gender-dependent norms.

Generalized muscular hypotonia (abnormally low muscle tone).

Chronic loss of joint motion in the 5th finger due to structural changes in non-bony tissue. The term camptodactyly of the 5th finger is used if the distal and/or proximal interphalangeal joints are affected.

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

An abnormal resistance to glucose, i.e., a reduction in the ability to maintain glucose levels in the blood stream within normal limits following oral or intravenous administration of glucose.

Glucose intolerance (GI) can be defined as dysglycemia that comprises both prediabetes and diabetes. It includes the conditions of impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) and diabetes mellitus (DM).

Distance between subnasale and pronasale more than two standard deviations above the mean, or alternatively, an apparently increased anterior protrusion of the nasal tip.

Increased thickness of the lower lip, leading to a prominent appearance of the lower lip. The height of the vermilion of the lower lip in the midline is more than 2 SD above the mean. Alternatively, an apparently increased height of the vermilion of the lower lip in the frontal view (subjective).

Width of the forehead or distance between the frontotemporales is more than two standard deviations above the mean (objective); or apparently increased distance between the two sides of the forehead.

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.

Increased length of the hairs of the eyebrows.

Bluish discoloration of the skin of the hands or feet.