What is Aniridia?

Note: Placing the mouse pointer over link words will display the description with most recent browser versions. If your browser does not support this OR if you use a screen reader, the links will take you to the description which are listed at the end of this document.

Aniridia by definitional terms means congenital absence or partial absence of the iris. However this is not the only feature of Aniridia, as will be discussed later.

Aniridia is rare. Its incidence is between 1/50,000 and 1/100,000. The genetic defect has been found to be a deletion on chromosome 11. It is an autosomal dominant condition in 2/3 of the cases. Approximately, a third of all cases of Aniridia are sporadic and these are often found to have cytogentically detectable deletions involving 11p13, which, if extensive enough, cause the WAGR contiguous gene syndrome .

As stated above, Aniridia is more than just being born without an Iris. Many aniridics have developmental and ocular abnormalities and may exhibit the presence of one or more of these associated ocular abnormalities:

• cataract
• lens dislocation
• foveal dysplasia
• optic nerve hypoplasia
• corneal pannus
• glaucoma
• nystagmus

For more detailed information on the subject of Aniridia, its associated conditions, and new research, please go to the Members' Area. If not currently a member, please register now so you can get the full benefit of the Aniridia Foundation Internationals resources.

Aniridia

The congenital absence or partial absence of the Iris. This condition usually carries with it other medical conditions.
Back to word

Autosomal Dominant

Means there is a familial or genetic tendency, i.e. one parent has Aniridia also.
Back to word

Bilateral Amblyopia

A reduction or dimness in vision.

Congenital

A person is born with this condition.
Back to word

Corneal Pannus

A scarring or clouding of corneal tissue which reduces visual acuity eventually to the point of only being able to see the contrast between light and dark. It is thought to happen to people with Aniridia due to the lack of working stem cells.
Back to word

Cytogenetically Detectable

Able to be detected through testing chromosomes (DNA)
Back to word

Glaucoma

The elevated intraocular pressure of the eyeball.
Back to word

Iris

The colored part of the eye that surrounds the black pupil in the center of the eye.
Back to word

Nystagmus

Constant, involuntary movement of eyeball. May be congenital and inapparent to the Aniridiac. Seen in bilateral amblyopia. It is as if the eye is searching for focus.
Back to word

Sporadic

Being born with Aniridia when neither parent exhibits the condition. No family history.
Back to word

WAGR (Contiguous Gene Snydrome)

Stands for the associated contitions possible.

• (W)ilms Tumor
• (A)niridia
• (G)enital/Urinary abnormalities
• (R)etardation)

Back to word

Wilms Tumor

A malignant kidney tumor usually appearing before age 6, but rare cases have seen it appear later. Most authorities seem to agree on a 3 month interval of ultrasound monitoring during the period of greatest risk, (birth to age 5) with a 6 month to 1 year interval thereafter. Consult your doctor.