انعدام القزحية

الوصف

Aniridia is an eye disorder that is characterised by a complete or partial absence of the colored part of the eye (the iris). Aniridia is typically present from birth (congenital) and affects both eyes. The pupils may also be abnormal or misshapen.

People with aniridia can have other eye problems that may be congenital or develop later in life. Clouding of the lenses of the eyes (cataracts) occurs in most people with aniridia. Affected individuals often have involuntary eye movements (nystagmus) or an increased sensitivity to light (photophobia). Underdevelopment of a specific region at the back of the eye (foveal hypoplasia) can reduce the sharpness of vision (visual acuity).

Additional signs and symptoms of aniridia may include problems with the cornea (aniridia-associated keratopathy). The cornea is the clear outer covering of the eye. Aniridia can also cause increased pressure in the eye (glaucoma) in late childhood through early adulthood. In some affected individuals, the structures that carry information from the eyes to the brain are underdeveloped (optic nerve hypoplasia). Many of these eye problems contribute to vision loss that worsens over time. The severity of symptoms is typically the same in both eyes.

In rare cases, individuals with aniridia have additional health problems, which can include behavioural issues, metabolic disorders, and problems detecting odors.

Aniridia can affect the eyes alone (isolated) or it can occur with other features as part of a syndrome. Aniridia is a common feature of certain genetic conditions including Gillespie syndrome and WAGR syndrome.

Injuries to the head or eyes can also cause aniridia. This type of aniridia is not genetic and can occur at any age.

Inheritance patterns

The source lists the following possible inheritance patterns: Autosomal dominant+Inherited or new variant. More than one pattern can apply in different cases.

Related genes

• PAX6

• ELP4

• TRIM44

Other names

Absent iris

Congenital aniridia

Irideremia