The presence of multiple cysts in both kidneys.

An anomaly of the intra-atrial or intraventricular septum.

Accumulation of fluid within the pericardium.

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

Accumulation of fluid in the peritoneal cavity.

Abnormally increased size of the liver.

Simultaneous enlargement of the liver and spleen.

Upper insertion of the ear to the scalp below an imaginary horizontal line drawn between the inner canthi of the eye and extending posteriorly to the ear.

A seizure is an intermittent abnormality of nervous system physiology characterised by a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain.

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

Unlocalized atrophy of the brain with decreased total brain matter volume and increased ventricular size.

A condition in which epileptiform abnormalities are believed to contribute to the progressive disturbance in cerebral function. Epileptic encephalaopathy is characterized by (1) electrographic EEG paroxysmal activity that is often aggressive, (2) seizures that are usually multiform and intractable, (3) cognitive, behavioral and neurological deficits that may be relentless, and (4) sometimes early death.

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.

Cerebellar atrophy is defined as a cerebellum with initially normal structures, in a posterior fossa with normal size, which displays enlarged fissures (interfolial spaces) in comparison to the foliae secondary to loss of tissue. Cerebellar atrophy implies irreversible loss of tissue and result from an ongoing progressive disease until a final stage is reached or a single injury, e.g. an intoxication or infectious event.

Subnormal intellectual functioning which originates during the developmental period. Intellectual disability, previously referred to as mental retardation, has been defined as an IQ score below 70.

Delayed myelination in the central nervous system.

Displacement of the femur from its normal location in the hip joint.

Exaggerated anterior convexity of the thoracic vertebral column.

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

An abnormality of skull shape characterized by a decreased anterior-posterior diameter. That is, a cephalic index greater than 81%. Alternatively, an apparently shortened anteroposterior dimension (length) of the head compared to width.

A general term describing features characterized by abnormal development of bones and connective tissues.

A decreased rate of skeletal maturation. Delayed skeletal maturation can be diagnosed on the basis of an estimation of the bone age from radiographs of specific bones in the human body.

Generalized muscular hypotonia (abnormally low muscle tone).

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

An abnormal accumulation of fluid beneath the skin, or in one or more cavities of the body.

Distance between the oral commissures more than 2 SD above the mean. Alternatively, an apparently increased width of the oral aperture (subjective).

An abnormal morphology (form) of the face or its components.

Diminished length of the neck.

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

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.

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 abnormal reduction in quantity or strength of fetal movements.

The presence of nipples that instead of pointing outward are retracted inwards.

A larger than usual distance between the left and right nipple.

A form of strabismus with one or both eyes turned inward ('crossed') to a relatively severe degree, usually defined as 10 diopters or more.

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).