An abnormal sensation of spinning while the body is actually stationary.

An abnormality of the pinna, which is also referred to as the auricle or external ear.

A severe form of sensorineural hearing impairment.

Cephalgia, or pain sensed in various parts of the head, not confined to the area of distribution of any nerve.

Hydrocephalus is an active distension of the ventricular system of the brain resulting from inadequate passage of CSF from its point of production within the cerebral ventricles to its point of absorption into the systemic circulation.

A discrete posterior fossa cerebrospinal fluid (CSF) collection that does not communicate directly with the fourth ventricle.

An increase in size of the ventricular system of the brain.

An abnormally decreased size of the pituitary gland.

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).

Adhesions between the iris and the cornea.

An abnormality of the cornea characterized by the deposition of calcium in a band across the central cornea, leading to decreased vision, foreign body sensation, and ocular irritation.

Diminished clarity of vision.

Intraocular pressure that is 2 standard deviations above the population mean.

Congenital underdevelopment of the iris.

Any abnormality of the electrical responses of various cell types in the retina as measured by electroretinography.

A pale yellow discoloration of the optic disc (the area of the optic nerve head in the retina). The optic disc normally has a pinkish hue with a central yellowish depression.

Anterior segment dysgeneses (ASGD or ASMD) are a heterogeneous group of developmental disorders affecting the anterior segment of the eye, including the cornea, iris, lens, trabecular meshwork, and Schlemm canal. The clinical features of ASGD include iris hypoplasia, an enlarged or reduced corneal diameter, corneal vascularization and opacity, posterior embryotoxon, corectopia, polycoria, an abnormal iridocorneal angle, ectopia lentis, and anterior synechiae between the iris and posterior corneal surface (summary by Cheong et al., 2016). Anterior segment dysgenesis is sometimes divided into subtypes including aniridia (see 106210), Axenfeld and Rieger anomalies, iridogoniodysgenesis, Peters anomaly, and posterior embryotoxon (Gould and John, 2002). Some patients with ASGD1 have been reported with the Peters anomaly subtype. In its simplest form, Peters anomaly involves a central corneal opacity, but it may also involve adherent iris strands. Some patients have keratolenticular content or cataract. The underlying defects in this form of congenital corneal opacity reside in the posterior stroma, Descemet membrane, and corneal endothelium. The disorder results from abnormal migration or function of neural crest cells and may include abnormalities of other anterior segment structures, such as the lens and iris (summary by Withers et al., 1999).