Abnormally long and slender fingers ("spider fingers").

A foot where the longitudinal arch of the foot is in contact with the ground or floor when the individual is standing; or, in a patient lying supine, a foot where the arch is in contact with the surface of a flat board pressed against the sole of the foot by the examiner with a pressure similar to that expected from weight bearing; or, the height of the arch is reduced.

An abnormally increased extension of the knee joint, so that the knee can bend backwards.

The legs angle inward, such that the knees are close together and the ankles far apart.

An outward deviation of the foot at the talocalcaneal or subtalar joint.

A height below that which is expected according to age and gender norms. Although there is no universally accepted definition of short stature, many refer to "short stature" as height more than 2 standard deviations below the mean for age and gender (or below the 3rd percentile for age and gender dependent norms).

Difficulty in swallowing.

Laterally protruding ear that lacks antihelical folding (including absence of inferior and superior crura).

Cerebellar ataxia refers to ataxia due to dysfunction of the cerebellum. This causes a variety of elementary neurological deficits including asynergy (lack of coordination between muscles, limbs and joints), dysmetria (lack of ability to judge distances that can lead to under- or overshoot in grasping movements), and dysdiadochokinesia (inability to perform rapid movements requiring antagonizing muscle groups to be switched on and off repeatedly).

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

Intellectual disability, previously referred to as mental retardation, is characterized by subnormal intellectual functioning that occurs during the developmental period. It is defined by an IQ score below 70.

Delayed myelination in the central nervous system.

Atrophy of the cortex of the cerebrum.

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.

Osteopenia is a term to define bone density that is not normal but also not as low as osteoporosis. By definition from the World Health Organization osteopenia is defined by bone densitometry as a T score -1 to -2.5.

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

Generalized muscular hypotonia (abnormally low muscle tone).

Occipitofrontal (head) circumference greater than 97th centile compared to appropriate, age matched, sex-matched normal standards. Alternatively, a apparently increased size of the cranium.

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

An increased concentration of cholesterol in the blood.

The facial appearance is more circular than usual as viewed from the front.

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).

The palpebral fissure inclination is more than two standard deviations below the mean.

Epicanthus is a condition in which a fold of skin stretches from the upper to the lower eyelid, partially covering the inner canthus. Usher (1935) noted that epicanthus is a normal finding in the fetus of all races. Epicanthus also occurs in association with hereditary ptosis (110100).

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

Distance between the hairline (trichion) and the glabella (the most prominent point on the frontal bone above the root of the nose), in the midline, more than two SD below the mean. Alternatively, an apparently decreased distance between the hairline and the glabella.

Increased breadth of the nasal bridge (and with it, the nasal root).

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.

Uvula separated into two parts most easily seen at the tip.

A type of hypothyroidism that results from a defect in the thyroid gland.

A hazy, grayish-white ring about 2 mm in width located close to but separated from the limbus (the corneoscleral junction). Corneal arcus generally occurs bilaterally, and is related to lipid deposition in the cornea. Corneal arcus can occur in elderly persons as a part of the aging process but may be associated with hypercholesterolemia in people under the age of 50 years.

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).

Nearsightedness, also known as myopia, is an eye condition that causes blurry distance vision. People who are nearsighted have more trouble seeing things that are far away (such as when driving) than things that are close up (such as when reading or using a computer). If it is not treated with corrective lenses or surgery, nearsightedness can lead to squinting, eyestrain, headaches, and significant visual impairment.\n\nNearsightedness usually begins in childhood or adolescence. It tends to worsen with age until adulthood, when it may stop getting worse (stabilize). In some people, nearsightedness improves in later adulthood.\n\nFor normal vision, light passes through the clear cornea at the front of the eye and is focused by the lens onto the surface of the retina, which is the lining of the back of the eye that contains light-sensing cells. People who are nearsighted typically have eyeballs that are too long from front to back. As a result, light entering the eye is focused too far forward, in front of the retina instead of on its surface. It is this change that causes distant objects to appear blurry. The longer the eyeball is, the farther forward light rays will be focused and the more severely nearsighted a person will be.\n\nNearsightedness is measured by how powerful a lens must be to correct it. The standard unit of lens power is called a diopter. Negative (minus) powered lenses are used to correct nearsightedness. The more severe a person's nearsightedness, the larger the number of diopters required for correction. In an individual with nearsightedness, one eye may be more nearsighted than the other.\n\nEye doctors often refer to nearsightedness less than -5 or -6 diopters as "common myopia." Nearsightedness of -6 diopters or more is commonly called "high myopia." This distinction is important because high myopia increases a person's risk of developing other eye problems that can lead to permanent vision loss or blindness. These problems include tearing and detachment of the retina, clouding of the lens (cataract), and an eye disease called glaucoma that is usually related to increased pressure within the eye. The risk of these other eye problems increases with the severity of the nearsightedness. The term "pathological myopia" is used to describe cases in which high myopia leads to tissue damage within the eye.

Primary or spontaneous detachment of the retina occurs due to underlying ocular disease and often involves the vitreous as well as the retina. The precipitating event is formation of a retinal tear or hole, which permits fluid to accumulate under the sensory layers of the retina and creates an intraretinal cleavage that destroys the neurosensory process of visual reception. Vitreoretinal degeneration and tear formation are painless phenomena, and in most cases, significant vitreoretinal pathology is found only after detachment of the retina starts to cause loss of vision or visual field. Without surgical intervention, retinal detachment will almost inevitably lead to total blindness (summary by McNiel and McPherson, 1971).

Megalocornea is an inherited eye disorder in which the corneal diameter is bilaterally enlarged (greater than 13 mm) without an increase in intraocular pressure. It may also be referred to as 'anterior megalophthalmos,' since the entire anterior segment is larger than normal. Features of megalocornea in addition to a deep anterior chamber include astigmatic refractive errors, atrophy of the iris stroma, miosis secondary to decreased function of the dilator muscle, iridodonesis, and tremulousness, subluxation, or dislocation of the lens. Whereas most affected individuals exhibit normal ocular function, complications include cataract development and glaucoma following lenticular dislocation or subluxation. X-linked recessive inheritance is the most common pattern, accounting for the male preponderance of the disorder (summary by Skuta et al., 1983). Megalocornea sometimes occurs as part of the Marfan syndrome (154700). Genetic Heterogeneity of Megalocornea Autosomal recessive megalocornea has been reported (249300).

Congenital underdevelopment of the iris.

Tremulousness of the iris on movement of the eye, occurring in subluxation of the lens.

An anomaly in the amount of force per unit area exerted by the intraocular fluid within the eye.

Transmission of light through the iris as visualized upon slit lamp examination or infrared iris transillumination videography. The light passes through defects in the pigmentation of the iris.